The Experts below are selected from a list of 1566 Experts worldwide ranked by ideXlab platform

Charles H. Cannon - One of the best experts on this subject based on the ideXlab platform.

  • Fruit development of Lithocarpus (Fagaceae) and the role of heterochrony in their evolution.
    Journal of plant research, 2020
    Co-Authors: Xi Chen, Takashi Kohyama, Charles H. Cannon
    Abstract:

    Stone oaks, or Lithocarpus species of Fagaceae are ecologically important canopy trees in the tropical and subtropical forests over East Asia, and the fruits of which are important food sources for insects and vertebrates there. The great fruit morphological variation of this genus represents two fruit types, acorn and enclosed receptacle fruit types. However, the evolutionary mechanisms of differentiation into these two fruit types with contrasting morphology remain a puzzle. To reveal the morphogenetic properties of two fruit types, we observed tissue differentiation and development among 20 Lithocarpus species from fruit set to maturity. Unlike in fruits of Quercus, the endocarp differentiation in Lithocarpus fruits occurred later than exocarp and mesocarp. Cupules provided further protection of developing seeds, particularly of acorn-type fruits. Fruits of Lithocarpus and Quercus acorns share similar insect predators. At fruit set, both acorn and enclosed receptacle types were largely identical, with similar tissue morphology and the sequence of differentiation. The distinct difference between two fruit types at maturity came from varied rates and degrees of development between the pericarp and receptacle tissues. We found that heterochrony between two tissues could create substantially divergent ecological strategies for protection and dispersal of their seeds, which is essential for the evolution of two fruit types.

  • Associated morphometric and geospatial differentiation among 98 species of stone oaks (Lithocarpus)
    2018
    Co-Authors: Xi Chen, Takashi S. Kohyama, Charles H. Cannon
    Abstract:

    Two fruit types can be distinguished among stone oaks (Lithocarpus) species: the ‘acorn’ (AC) and the ‘enclosed receptacle’ (ER) types. Our morphometric analysis of 595 nuts from 98 species (one third of all Lithocarpus spp.) found substantial transition in mechanical protection of the seed between two woody fruit tissues (exocarp and receptacle) of two fruit types. AC fruits were smaller in seed and fruit size and the thin brittle exocarp largely enclosed the seed, whereas ER fruits were larger and the seed was mostly enclosed by thick woody receptacle tissue. The differences in these two tissues were considerably greater between compared to within fruit type and species. Geospatial distribution showed that seed size of all examined species increased with elevation and decreased with latitude, the physical defense increased with both elevation and latitude, and ER-fruit species were more common at higher elevation. The two fruit types represent distinct suites of associated traits that respond differently to the various biotic and abiotic factors associated with geographic variation, profoundly impacting the evolution of the two fruit types. The co-occurrence of two fruit types in the same forest could be a consequence of distinct fruit and animal interactions.

  • Patterns of genomic diversification reflect differences in life history and reproductive biology between figs (Ficus) and the stone oaks (Lithocarpus).
    Genome, 2017
    Co-Authors: Chai-shian Kua, Charles H. Cannon
    Abstract:

    One of the remarkable aspects of the tremendous biodiversity found in tropical forests is the wide range of evolutionary strategies that have produced this diversity, indicating many paths to diversification. We compare two diverse groups of trees with profoundly different biologies to discover whether these differences are reflected in their genomes. Ficus (Moraceae), with its complex co-evolutionary relationship with obligate pollinating wasps, produces copious tiny seeds that are widely dispersed. Lithocarpus (Fagaceae), with generalized insect pollination, produces large seeds that are poorly dispersed. We hypothesize that these different reproductive biologies and life history strategies should have a profound impact on the basic properties of genomic divergence within each genus. Using shallow whole genome sequencing for six species of Ficus, seven species of Lithocarpus, and three outgroups, we examined overall genomic diversity, how it is shared among the species within each genus, and the fraction of this shared diversity that agrees with the major phylogenetic pattern. A substantially larger fraction of the genome is shared among species of Lithocarpus, a considerable amount of this shared diversity was incongruent with the general background history of the genomes, and each fig species possessed a substantially larger fraction of unique diversity than Lithocarpus.

  • patterns of genomic diversification reflect differences in life history and reproductive biology between figs ficus and the stone oaks Lithocarpus
    Genome, 2017
    Co-Authors: Chai-shian Kua, Charles H. Cannon
    Abstract:

    One of the remarkable aspects of the tremendous biodiversity found in tropical forests is the wide range of evolutionary strategies that have produced this diversity, indicating many paths to diversification. We compare two diverse groups of trees with profoundly different biologies to discover whether these differences are reflected in their genomes. Ficus (Moraceae), with its complex co-evolutionary relationship with obligate pollinating wasps, produces copious tiny seeds that are widely dispersed. Lithocarpus (Fagaceae), with generalized insect pollination, produces large seeds that are poorly dispersed. We hypothesize that these different reproductive biologies and life history strategies should have a profound impact on the basic properties of genomic divergence within each genus. Using shallow whole genome sequencing for six species of Ficus, seven species of Lithocarpus, and three outgroups, we examined overall genomic diversity, how it is shared among the species within each genus, and the fractio...

  • (Lithocarpus) Seeds between Physical and Chemical Defense Highlights Fiber as an Important Antifeedant
    2016
    Co-Authors: Xi Chen, Charles H. Cannon, Nancy Lou Conklin-brittan
    Abstract:

    (Article begins on next page) The Harvard community has made this article openly available. Please share how this access benefits you. Your story matters. Citation Chen, Xi, Charles H. Cannon, and Nancy Lou Conklin-Brittan.2012. Evidence for a trade-off strategy in stone oak (Lithocarpus) seeds between physical and chemical defense highlights fiber as an important antifeedant. PLoS ONE 7(3): e32890. Published Version doi:10.1371/journal.pone.003289

Paul S. Manos - One of the best experts on this subject based on the ideXlab platform.

  • Phylogenetic Relationships and Taxonomic Status Of the Paleoendemic Fagaceae Of Western North America: Recognition Of A New Genus, NothoLithocarpus
    Madroño, 2008
    Co-Authors: Paul S. Manos, Charles H. Cannon
    Abstract:

    Abstract We investigated the phylogenetic relationships and taxonomic status of the castaneoid component (Lithocarpus and Chrysolepis) of the family Fagaceae that is endemic to the California Floristic Province (CA-FP). Over 7800 basepairs of nuclear and chloroplast DNA were analyzed in 17 taxa representing the breadth of phylogenetic diversity in the family. The genus Lithocarpus, as currently defined, is clearly polyphyletic due to the inclusion of L. densiflorus. Here, we designate this taxon as a new genus, NothoLithocarpus, which can be recognized morphologically by its relatively small, subprolate pollen. NothoLithocarpus is more closely related to Quercus, Castanea, and Castanopsis; Chrysolepis was resolved as the sister group to Lithocarpus sensu stricto. These results indicate that NothoLithocarpus does not possess true ‘flower cupules,’ which define Lithocarpus sensu stricto, but like the oaks, the single flower per cupule is derived through the abortion of lateral flowers within each cupule. Fu...

  • phylogeography of the southeast asian stone oaks Lithocarpus
    Journal of Biogeography, 2003
    Co-Authors: Charles H. Cannon, Paul S. Manos
    Abstract:

    Aim  To describe current geographical patterns of genetic diversity and infer the historical population dynamics of the stone oaks (Lithocarpus) in Southeast Asia. Location  We sampled three populations in Indochina: (1) Yunnan province, China; (2) Pyin Oo Lwin area, Myanmar and (3) north-western Vietnam; two in western Borneo: (1) South-western Sarawak and (2) West Kalimantan, Indonesia; two in central Borneo: (1) north coastal Sarawak and (2) north-eastern Sarawak, Malaysia; and two in northern Borneo: (1) Central Sabah and (2) Northern Sabah, Malaysia. Methods  A phylogenetic reconstruction of chloroplast DNA sequence variation from numerous individuals of multiple species was used to determine geographical distribution of genetic diversity. A resampling scheme was used to determine the significance of these patterns at different hierarchical levels of the phylogeny. Results were compared with a previously published set of nuclear DNA sequence data. Results  A high level of chloroplast sequence variation was found, which was divided equally between two major clades separated by four non-homoplasious changes. One clade was confined to the island of Borneo, while the other was widespread. Strong geographical structure was observed in the chloroplast sequence variation. The Indo-chinese populations were much more closely related than expected, comparable with the highly endemic and isolated population on the western coast of Borneo. Conversely, individuals from the Kelabit Highlands were found to be more distantly related than expected. The highest levels of genetic endemism were observed in western Borneo. More geographical structure was observed in the Bornean clade than in the Widespread clade, because of limited genetic diversity in the Widespread clade. Relatively weak geographical structure was found in the nuclear sequence variation: only populations in southern China and central Sabah were significantly related. Conclusions  The high levels of chloroplast genetic diversity and the persistence of an ancestral haplotype that is a single step away from a haplotype found in Castanopsis indicates the continuous presence of tropical rain forest in Southeast Asia throughout the evolutionary history of the genus (c. 40 Myr). This conclusion is supported by the high frequency of numerous endemic types observed in every population and the relatively few number of ‘missing’ haplotypes. This situation suggests both limited migration and limited extinction. In contrast, the nuclear genetic diversity contained less geographical structure, indicating that our taxonomic sampling among populations was unbiased and that gene flow mediated through pollen is less geographically restricted and contains less geographical structure than purely seed-mediated (chloroplast) gene flow. The most likely scenario suggested by the evidence involves four major patterns: (1) the widespread presence of an ancestral haplotype; (2) the large degree of separation (four non-homoplasious base pairs) between the types found in the two major clades; (3) the concentration of derived types from both major clades found in central and northern Borneo; and (4) the molecular endemism found in each location. These patterns suggest four primary things about the population dynamics of Lithocarpus since the late Eocene: (1) populations have either spanned the entire region throughout much of the evolutionary history of the genus or substantial populations have persisted in both Indochina and Borneo with limited migration between them; (2) significant fragmentation has occurred subsequently between the Asian mainland and the Melasian island archipelago, leading to independent genetic diversification in both regions; (3) several locations possessing significant independent histories, have experienced little migration and have never gone completely extinct; and (4) that the central highlands of Borneo have been re-invaded from the north and the west. The timing of these events is difficult to ascertain but probably predate the Quaternary Period, suggesting that although the recent ice ages might have affected the overall distribution of rain forest in Southeast Asia, it managed to persist in most regions even through the most dramatic drying events.

  • Combining and Comparing Morphometric Shape Descriptors with a Molecular Phylogeny: The Case of Fruit Type Evolution in Bornean Lithocarpus (Fagaceae)
    Systematic biology, 2001
    Co-Authors: Charles H. Cannon, Paul S. Manos
    Abstract:

    Fruit type in the genus Lithocarpus (Fagaceae) includes both classic oak acorns and novel modifications. Bornean taxa with modified fruits can be separated into two sections (Synaedrys and Lithocarpus) based on subtle shape differences. By following strict criteria for homology and representation, this variation in shape can be captured and the sections distinguished by using elliptic Fourier or eigenshape analysis. Phenograms of fruit shape, constructed by using restricted maximum likelihood techniques and these morphometric descriptors, were incorporated into combined and comparative analyses with molecular sequence data from the internal transcribed spacer (ITS) region of the nuclear rDNA, using branch-weighted matrix representation. The combined analysis strongly suggested independent derivation of the novel fruit type in the two sections from different acornlike ancestors, while the comparative analysis indicated frequent decoupling between the molecular and morphological changes as inferred at well-supported nodes. The acorn fruit type has undergone little modification between ingroup and outgroup, despite large molecular distance. Greater morphological than molecular change was inferred at critical transitions between acorn and novel fruit types, particularly for section Lithocarpus. The combination of these two different types of data improved our understanding of the macroevolution of fruit type in this difficult group, and the comparative analysis highlighted the significant incongruities in evolutionary pattern between the two datasets.

  • combining and comparing morphometric shape descriptors with a molecular phylogeny the case of fruit type evolution in bornean Lithocarpus fagaceae
    Systematic Biology, 2001
    Co-Authors: Charles H. Cannon, Paul S. Manos
    Abstract:

    Fruit type in the genus Lithocarpus (Fagaceae) includes both classic oak acorns and novel modiecations. Bornean taxa with modieed fruits can be separated into two sections (Synaedrys and Lithocarpus) based on subtle shape differences. By following strict criteria for homology and repre- sentation, this variation in shape can be captured and the sections distinguished by using elliptic Fourier or eigenshape analysis. Phenograms of fruit shape, constructed by using restricted maximum likelihood techniques and these morphometric descriptors, were incorporated into combined and comparative analyses with molecular sequence data from the internal transcribed spacer (ITS) region of the nuclear rDNA, using branch-weighted matrix representation. The combined analysis strongly suggested independent derivation of the novel fruit type in the two sections from different acorn- like ancestors, while the comparative analysis indicated frequent decoupling between the molecular and morphological changes as inferred at well-supported nodes. The acorn fruit type has under- gone little modiecation between ingroup and outgroup, despite large molecular distance. Greater morphological than molecular change was inferred at critical transitions between acorn and novel fruit types, particularly for section Lithocarpus. The combination of these two different types of data improved our understanding of the macroevolution of fruit type in this difecult group, and the com- parative analysis highlighted the signiecant incongruities in evolutionary pattern between the two datasets. (Branch length estimates; continuous characters; eigenshape; enclosed receptacle; Fourier; matrix representation.)

Pei Chun Liao - One of the best experts on this subject based on the ideXlab platform.

  • Nuclear and chloroplast DNA phylogeography suggests an Early Miocene southward expansion of Lithocarpus (Fagaceae) on the Asian continent and islands
    Botanical studies, 2018
    Co-Authors: Chih Kai Yang, Yu-chung Chiang, Bing Hong Huang, Pei Chun Liao
    Abstract:

    Most genera of Fagaceae are thought to have originated in the temperate regions except for the genus Lithocarpus, the stone oaks. Lithocarpus is distributed in subtropical and tropical Asia, and its ancestral population is hypothesized to be distributed in tropical regions in Borneo and Indochina. Borneo and the nearby islands (the Greater Sunda Islands) were connected to the Malay Peninsula and Indochina prior to the Pliocene epoch and formed the former Sundaland continent. The Southeast Asian Lithocarpus, is thought to have dispersed between continental Asia and the present Sundaland. The drastic climate changes during the Pliocene and Pleistocene epochs which caused periodic sea-level changes is often used to explain the cause of its diversity. The aim of this study was to establish phylogenetic relationships by analyzing nuclear (nrDNA) and chloroplast (cpDNA) DNA in order to describe and analyze the origin, causes of diversification and historical biogeography of Lithocarpus. Phylogeny reconstructed through the multiple-species coalescent method with nrDNA and cpDNA revealed that the continental-Asian taxa were clustered at the basal lineages. The derived lineages of tropical Lithocarpus, with the inference of a subtropical ancestral state, imply a southward migration in the Early Miocene period with subsequent in situ diversification in the Greater Sunda Islands. The gradual decrease in temperature since the Middle Miocene period is proposed as a cause of the increase in the net diversification rate. The historical ancestral origin of Lithocarpus has been suggested to be mainland Asia. Southward migration in the Early Miocene period with subsequent in situ diversification could explain the current diversity of stone oaks in Southeast Asia. This study also considered the multiple origins of stone oaks currently indigenous to the subtropical islands offshore and near mainland China. Our results provide phylogenetic evidence for a subtropical origin of Asian stone oaks and reveal the process of diversification and how it fits into the timeline of major geologic and climatic events rather than local, episodic, rate-shifting events.

  • Molecular genetic and biochemical evidence for adaptive evolution of leaf abaxial epicuticular wax crystals in the genus Lithocarpus (Fagaceae).
    BMC plant biology, 2018
    Co-Authors: Chih Kai Yang, Bing Hong Huang, Meng-yuan Huang, Jenn-che Wang, Jian Gao, Pei Chun Liao
    Abstract:

    Leaf epicuticular wax is an important functional trait for physiological regulation and pathogen defense. This study tests how selective pressure may have forced the trait of leaf abaxial epicuticular wax crystals (LAEWC) and whether the presence/absence of LAEWC is associated with other ecophysiological traits. Scanning Electron Microscopy was conducted to check for LAEWC in different Lithocarpus species. Four wax biosynthesis related genes, including two wax backbone genes ECERIFERUM 1 (CER1) and CER3, one regulatory gene CER7 and one transport gene CER5, were cloned and sequenced. Ecophysiological measurements of secondary metabolites, photosynthesis, water usage efficiency, and nutrition indices were also determined. Evolutionary hypotheses of leaf wax character transition associated with the evolution of those ecophysiological traits as well as species evolution were tested by maximum likelihood. Eight of 14 studied Lithocarpus species have obvious LAEWC appearing with various types of trichomes. Measurements of ecophysiological traits show no direct correlations with the presence/absence of LAEWC. However, the content of phenolic acids is significantly associated with the gene evolution of the wax biosynthetic backbone gene CER1, which was detected to be positively selected when LAEWC was gained during the late-Miocene-to-Pliocene period. Changes of landmass and vegetation type accelerated the diversification of tropical and subtropical forest trees and certain herbivores during the late Miocene. As phenolic acids were long thought to be associated with defense against herbivories, co-occurrence of LAEWC and phenolic acids may suggest that LAEWC might be an adaptive defensive mechanism in Lithocarpus.

  • Nuclear and chloroplast DNA phylogeography suggests an Early Miocene southward expansion of Lithocarpus (Fagaceae) on the Asian continent and islands
    SpringerOpen, 2018
    Co-Authors: Chih Kai Yang, Yu-chung Chiang, Bing Hong Huang, Pei Chun Liao
    Abstract:

    Abstract Background Most genera of Fagaceae are thought to have originated in the temperate regions except for the genus Lithocarpus, the stone oaks. Lithocarpus is distributed in subtropical and tropical Asia, and its ancestral population is hypothesized to be distributed in tropical regions in Borneo and Indochina. Borneo and the nearby islands (the Greater Sunda Islands) were connected to the Malay Peninsula and Indochina prior to the Pliocene epoch and formed the former Sundaland continent. The Southeast Asian Lithocarpus, is thought to have dispersed between continental Asia and the present Sundaland. The drastic climate changes during the Pliocene and Pleistocene epochs which caused periodic sea-level changes is often used to explain the cause of its diversity. The aim of this study was to establish phylogenetic relationships by analyzing nuclear (nrDNA) and chloroplast (cpDNA) DNA in order to describe and analyze the origin, causes of diversification and historical biogeography of Lithocarpus. Results Phylogeny reconstructed through the multiple-species coalescent method with nrDNA and cpDNA revealed that the continental-Asian taxa were clustered at the basal lineages. The derived lineages of tropical Lithocarpus, with the inference of a subtropical ancestral state, imply a southward migration in the Early Miocene period with subsequent in situ diversification in the Greater Sunda Islands. The gradual decrease in temperature since the Middle Miocene period is proposed as a cause of the increase in the net diversification rate. Conclusions The historical ancestral origin of Lithocarpus has been suggested to be mainland Asia. Southward migration in the Early Miocene period with subsequent in situ diversification could explain the current diversity of stone oaks in Southeast Asia. This study also considered the multiple origins of stone oaks currently indigenous to the subtropical islands offshore and near mainland China. Our results provide phylogenetic evidence for a subtropical origin of Asian stone oaks and reveal the process of diversification and how it fits into the timeline of major geologic and climatic events rather than local, episodic, rate-shifting events

  • Additional file 1: of Molecular genetic and biochemical evidence for adaptive evolution of leaf abaxial epicuticular wax crystals in the genus Lithocarpus (Fagaceae)
    2018
    Co-Authors: Chih Kai Yang, Bing Hong Huang, Meng-yuan Huang, Jenn-che Wang, Jian Gao, Pei Chun Liao
    Abstract:

    Figure S1. Detail of adaxial layer of leaf epidermis of the genus Lithocarpus using Scanning Electron Microscope (SEM). (A) L. amygdalifolius; (B) L. brevicaudatus; (C) L. cornea; (D) L. dodonaeifolius; (E) L. formosanus; (F) L. glaber; (G) L. hanceii; (H) L. harlandii; (I) L. kawakamii; (J) L. konishii; (K) L. lepidocarpus; (L) L. nantoensis; (M) L. shinsuiensis; (N) L. taitoensisx. The SEM shows that no epicuticular wax crystals covered the leaf adaxial leaf surface in Lithocarpus. The scale bar represents 200 Οm. Figure S2. The spatial distribution reconstructed according to the current sampling records from GBIF and predicted using a machine-learning algorithm, maximum entropy algorithms, implemented in Maxent [79]. Figure S3. Ancestral state inference of discrete characters using the Maximum likelihood framework assuming one-parameter equal rates (ER) of character transition model and summarizing the 300 simulated character reconstructions. Figure S4. Pairwise comparison of substitution rates (K) of LAEWC related genes and reference genes using simple linear regression (SLR) and dependent two-group Wilcoxon Signed Rank Test (WSRT). Table S1. Primer list and annealing temperatures used in this study. Table S2. Results of likelihood ratio test of hypotheses of positive selection on retaining the gain or loss of LAEWC trait. Table S3. Ecophysiological measurements and altitudinal distribution of Lithocarpus species tested in this study. (PDF 1094 kb

  • Molecular genetic and biochemical evidence for adaptive evolution of leaf abaxial epicuticular wax crystals in the genus Lithocarpus (Fagaceae)
    BMC, 2018
    Co-Authors: Chih Kai Yang, Bing Hong Huang, Meng-yuan Huang, Jenn-che Wang, Jian Gao, Pei Chun Liao
    Abstract:

    Abstract Background Leaf epicuticular wax is an important functional trait for physiological regulation and pathogen defense. This study tests how selective pressure may have forced the trait of leaf abaxial epicuticular wax crystals (LAEWC) and whether the presence/absence of LAEWC is associated with other ecophysiological traits. Scanning Electron Microscopy was conducted to check for LAEWC in different Lithocarpus species. Four wax biosynthesis related genes, including two wax backbone genes ECERIFERUM 1 (CER1) and CER3, one regulatory gene CER7 and one transport gene CER5, were cloned and sequenced. Ecophysiological measurements of secondary metabolites, photosynthesis, water usage efficiency, and nutrition indices were also determined. Evolutionary hypotheses of leaf wax character transition associated with the evolution of those ecophysiological traits as well as species evolution were tested by maximum likelihood. Results Eight of 14 studied Lithocarpus species have obvious LAEWC appearing with various types of trichomes. Measurements of ecophysiological traits show no direct correlations with the presence/absence of LAEWC. However, the content of phenolic acids is significantly associated with the gene evolution of the wax biosynthetic backbone gene CER1, which was detected to be positively selected when LAEWC was gained during the late-Miocene-to-Pliocene period. Conclusions Changes of landmass and vegetation type accelerated the diversification of tropical and subtropical forest trees and certain herbivores during the late Miocene. As phenolic acids were long thought to be associated with defense against herbivories, co-occurrence of LAEWC and phenolic acids may suggest that LAEWC might be an adaptive defensive mechanism in Lithocarpus

Xi Chen - One of the best experts on this subject based on the ideXlab platform.

  • Fruit development of Lithocarpus (Fagaceae) and the role of heterochrony in their evolution.
    Journal of plant research, 2020
    Co-Authors: Xi Chen, Takashi Kohyama, Charles H. Cannon
    Abstract:

    Stone oaks, or Lithocarpus species of Fagaceae are ecologically important canopy trees in the tropical and subtropical forests over East Asia, and the fruits of which are important food sources for insects and vertebrates there. The great fruit morphological variation of this genus represents two fruit types, acorn and enclosed receptacle fruit types. However, the evolutionary mechanisms of differentiation into these two fruit types with contrasting morphology remain a puzzle. To reveal the morphogenetic properties of two fruit types, we observed tissue differentiation and development among 20 Lithocarpus species from fruit set to maturity. Unlike in fruits of Quercus, the endocarp differentiation in Lithocarpus fruits occurred later than exocarp and mesocarp. Cupules provided further protection of developing seeds, particularly of acorn-type fruits. Fruits of Lithocarpus and Quercus acorns share similar insect predators. At fruit set, both acorn and enclosed receptacle types were largely identical, with similar tissue morphology and the sequence of differentiation. The distinct difference between two fruit types at maturity came from varied rates and degrees of development between the pericarp and receptacle tissues. We found that heterochrony between two tissues could create substantially divergent ecological strategies for protection and dispersal of their seeds, which is essential for the evolution of two fruit types.

  • Associated morphometric and geospatial differentiation among 98 species of stone oaks (Lithocarpus)
    2018
    Co-Authors: Xi Chen, Takashi S. Kohyama, Charles H. Cannon
    Abstract:

    Two fruit types can be distinguished among stone oaks (Lithocarpus) species: the ‘acorn’ (AC) and the ‘enclosed receptacle’ (ER) types. Our morphometric analysis of 595 nuts from 98 species (one third of all Lithocarpus spp.) found substantial transition in mechanical protection of the seed between two woody fruit tissues (exocarp and receptacle) of two fruit types. AC fruits were smaller in seed and fruit size and the thin brittle exocarp largely enclosed the seed, whereas ER fruits were larger and the seed was mostly enclosed by thick woody receptacle tissue. The differences in these two tissues were considerably greater between compared to within fruit type and species. Geospatial distribution showed that seed size of all examined species increased with elevation and decreased with latitude, the physical defense increased with both elevation and latitude, and ER-fruit species were more common at higher elevation. The two fruit types represent distinct suites of associated traits that respond differently to the various biotic and abiotic factors associated with geographic variation, profoundly impacting the evolution of the two fruit types. The co-occurrence of two fruit types in the same forest could be a consequence of distinct fruit and animal interactions.

  • (Lithocarpus) Seeds between Physical and Chemical Defense Highlights Fiber as an Important Antifeedant
    2016
    Co-Authors: Xi Chen, Charles H. Cannon, Nancy Lou Conklin-brittan
    Abstract:

    (Article begins on next page) The Harvard community has made this article openly available. Please share how this access benefits you. Your story matters. Citation Chen, Xi, Charles H. Cannon, and Nancy Lou Conklin-Brittan.2012. Evidence for a trade-off strategy in stone oak (Lithocarpus) seeds between physical and chemical defense highlights fiber as an important antifeedant. PLoS ONE 7(3): e32890. Published Version doi:10.1371/journal.pone.003289

  • Evidence for a Trade-Off Strategy in Stone Oak (Lithocarpus) Seeds between Physical and Chemical Defense Highlights Fiber as an Important Antifeedant
    PloS one, 2012
    Co-Authors: Xi Chen, Charles H. Cannon, Nancy Lou Conklin-brittan
    Abstract:

    Trees in the beech or oak family (Fagaceae) have a mutualistic relationship with scatter-hoarding rodents. Rodents obtain nutrients and energy by consuming seeds, while providing seed dispersal for the tree by allowing some cached seeds to germinate. Seed predation and caching behavior of rodents is primarily affected by seed size, mechanical protection, macronutrient content, and chemical antifeedants. To enhance seed dispersal, trees must optimize trade-offs in investment between macronutrients and antifeedants. Here, we examine this important chemical balance in the seeds of tropical stone oak species with two substantially different fruit morphologies. These two distinct fruit morphologies in Lithocarpus differ in the degree of mechanical protection of the seed. For ‘acorn’ fruit, a thin exocarp forms a shell around the seed while for ‘enclosed receptacle’ (ER) fruit, the seed is embedded in a woody receptacle. We compared the chemical composition of numerous macronutrient and antifeedant in seeds from several Lithocarpus species, focusing on two pairs of sympatric species with different fruit morphologies. We found that macronutrients, particularly total non-structural carbohydrate, was more concentrated in seeds of ER fruits while antifeedants, primarily fibers, were more concentrated in seeds of acorn fruits. The trade-off in these two major chemical components was more evident between the two sympatric lowland species than between two highland species. Surprisingly, no significant difference in overall tannin concentrations in the seeds was observed between the two fruit morphologies. Instead, the major trade-off between macronutrients and antifeedants involved indigestible fibers. Future studies of this complex mutualism should carefully consider the role of indigestible fibers in the foraging behavior of scatter-hoarding rodents.

  • Lithocarpus pulongtauensis fagaceae a new species from borneo
    Annales Botanici Fennici, 2011
    Co-Authors: Charles H. Cannon, Xi Chen
    Abstract:

    We describe a new species of Lithocarpus from the central Kelabit Highlands of Sarawak, Malaysia with a distribution extending north to Mt. Kinabalu, Sabah. This species was included in a previous morphometric and phylogenetic study of the section Synaedrys, mistakenly identified as L. rotundatus. Several individuals were observed on the western slopes of Mt. Kinabalu between the elevation of 1200–1500 meters. The species has a distinctive cupule, which usually completely encloses the nut and is very dark in color, almost black with a brittle texture similar to charcoal. The fruit is semi-hemispheric in shape and the bracts on the cupule are entirely fused, relatively sparse, stiff, brittle, and prominent.

Chih Kai Yang - One of the best experts on this subject based on the ideXlab platform.

  • Nuclear and chloroplast DNA phylogeography suggests an Early Miocene southward expansion of Lithocarpus (Fagaceae) on the Asian continent and islands
    Botanical studies, 2018
    Co-Authors: Chih Kai Yang, Yu-chung Chiang, Bing Hong Huang, Pei Chun Liao
    Abstract:

    Most genera of Fagaceae are thought to have originated in the temperate regions except for the genus Lithocarpus, the stone oaks. Lithocarpus is distributed in subtropical and tropical Asia, and its ancestral population is hypothesized to be distributed in tropical regions in Borneo and Indochina. Borneo and the nearby islands (the Greater Sunda Islands) were connected to the Malay Peninsula and Indochina prior to the Pliocene epoch and formed the former Sundaland continent. The Southeast Asian Lithocarpus, is thought to have dispersed between continental Asia and the present Sundaland. The drastic climate changes during the Pliocene and Pleistocene epochs which caused periodic sea-level changes is often used to explain the cause of its diversity. The aim of this study was to establish phylogenetic relationships by analyzing nuclear (nrDNA) and chloroplast (cpDNA) DNA in order to describe and analyze the origin, causes of diversification and historical biogeography of Lithocarpus. Phylogeny reconstructed through the multiple-species coalescent method with nrDNA and cpDNA revealed that the continental-Asian taxa were clustered at the basal lineages. The derived lineages of tropical Lithocarpus, with the inference of a subtropical ancestral state, imply a southward migration in the Early Miocene period with subsequent in situ diversification in the Greater Sunda Islands. The gradual decrease in temperature since the Middle Miocene period is proposed as a cause of the increase in the net diversification rate. The historical ancestral origin of Lithocarpus has been suggested to be mainland Asia. Southward migration in the Early Miocene period with subsequent in situ diversification could explain the current diversity of stone oaks in Southeast Asia. This study also considered the multiple origins of stone oaks currently indigenous to the subtropical islands offshore and near mainland China. Our results provide phylogenetic evidence for a subtropical origin of Asian stone oaks and reveal the process of diversification and how it fits into the timeline of major geologic and climatic events rather than local, episodic, rate-shifting events.

  • Molecular genetic and biochemical evidence for adaptive evolution of leaf abaxial epicuticular wax crystals in the genus Lithocarpus (Fagaceae).
    BMC plant biology, 2018
    Co-Authors: Chih Kai Yang, Bing Hong Huang, Meng-yuan Huang, Jenn-che Wang, Jian Gao, Pei Chun Liao
    Abstract:

    Leaf epicuticular wax is an important functional trait for physiological regulation and pathogen defense. This study tests how selective pressure may have forced the trait of leaf abaxial epicuticular wax crystals (LAEWC) and whether the presence/absence of LAEWC is associated with other ecophysiological traits. Scanning Electron Microscopy was conducted to check for LAEWC in different Lithocarpus species. Four wax biosynthesis related genes, including two wax backbone genes ECERIFERUM 1 (CER1) and CER3, one regulatory gene CER7 and one transport gene CER5, were cloned and sequenced. Ecophysiological measurements of secondary metabolites, photosynthesis, water usage efficiency, and nutrition indices were also determined. Evolutionary hypotheses of leaf wax character transition associated with the evolution of those ecophysiological traits as well as species evolution were tested by maximum likelihood. Eight of 14 studied Lithocarpus species have obvious LAEWC appearing with various types of trichomes. Measurements of ecophysiological traits show no direct correlations with the presence/absence of LAEWC. However, the content of phenolic acids is significantly associated with the gene evolution of the wax biosynthetic backbone gene CER1, which was detected to be positively selected when LAEWC was gained during the late-Miocene-to-Pliocene period. Changes of landmass and vegetation type accelerated the diversification of tropical and subtropical forest trees and certain herbivores during the late Miocene. As phenolic acids were long thought to be associated with defense against herbivories, co-occurrence of LAEWC and phenolic acids may suggest that LAEWC might be an adaptive defensive mechanism in Lithocarpus.

  • Nuclear and chloroplast DNA phylogeography suggests an Early Miocene southward expansion of Lithocarpus (Fagaceae) on the Asian continent and islands
    SpringerOpen, 2018
    Co-Authors: Chih Kai Yang, Yu-chung Chiang, Bing Hong Huang, Pei Chun Liao
    Abstract:

    Abstract Background Most genera of Fagaceae are thought to have originated in the temperate regions except for the genus Lithocarpus, the stone oaks. Lithocarpus is distributed in subtropical and tropical Asia, and its ancestral population is hypothesized to be distributed in tropical regions in Borneo and Indochina. Borneo and the nearby islands (the Greater Sunda Islands) were connected to the Malay Peninsula and Indochina prior to the Pliocene epoch and formed the former Sundaland continent. The Southeast Asian Lithocarpus, is thought to have dispersed between continental Asia and the present Sundaland. The drastic climate changes during the Pliocene and Pleistocene epochs which caused periodic sea-level changes is often used to explain the cause of its diversity. The aim of this study was to establish phylogenetic relationships by analyzing nuclear (nrDNA) and chloroplast (cpDNA) DNA in order to describe and analyze the origin, causes of diversification and historical biogeography of Lithocarpus. Results Phylogeny reconstructed through the multiple-species coalescent method with nrDNA and cpDNA revealed that the continental-Asian taxa were clustered at the basal lineages. The derived lineages of tropical Lithocarpus, with the inference of a subtropical ancestral state, imply a southward migration in the Early Miocene period with subsequent in situ diversification in the Greater Sunda Islands. The gradual decrease in temperature since the Middle Miocene period is proposed as a cause of the increase in the net diversification rate. Conclusions The historical ancestral origin of Lithocarpus has been suggested to be mainland Asia. Southward migration in the Early Miocene period with subsequent in situ diversification could explain the current diversity of stone oaks in Southeast Asia. This study also considered the multiple origins of stone oaks currently indigenous to the subtropical islands offshore and near mainland China. Our results provide phylogenetic evidence for a subtropical origin of Asian stone oaks and reveal the process of diversification and how it fits into the timeline of major geologic and climatic events rather than local, episodic, rate-shifting events

  • Additional file 1: of Molecular genetic and biochemical evidence for adaptive evolution of leaf abaxial epicuticular wax crystals in the genus Lithocarpus (Fagaceae)
    2018
    Co-Authors: Chih Kai Yang, Bing Hong Huang, Meng-yuan Huang, Jenn-che Wang, Jian Gao, Pei Chun Liao
    Abstract:

    Figure S1. Detail of adaxial layer of leaf epidermis of the genus Lithocarpus using Scanning Electron Microscope (SEM). (A) L. amygdalifolius; (B) L. brevicaudatus; (C) L. cornea; (D) L. dodonaeifolius; (E) L. formosanus; (F) L. glaber; (G) L. hanceii; (H) L. harlandii; (I) L. kawakamii; (J) L. konishii; (K) L. lepidocarpus; (L) L. nantoensis; (M) L. shinsuiensis; (N) L. taitoensisx. The SEM shows that no epicuticular wax crystals covered the leaf adaxial leaf surface in Lithocarpus. The scale bar represents 200 Οm. Figure S2. The spatial distribution reconstructed according to the current sampling records from GBIF and predicted using a machine-learning algorithm, maximum entropy algorithms, implemented in Maxent [79]. Figure S3. Ancestral state inference of discrete characters using the Maximum likelihood framework assuming one-parameter equal rates (ER) of character transition model and summarizing the 300 simulated character reconstructions. Figure S4. Pairwise comparison of substitution rates (K) of LAEWC related genes and reference genes using simple linear regression (SLR) and dependent two-group Wilcoxon Signed Rank Test (WSRT). Table S1. Primer list and annealing temperatures used in this study. Table S2. Results of likelihood ratio test of hypotheses of positive selection on retaining the gain or loss of LAEWC trait. Table S3. Ecophysiological measurements and altitudinal distribution of Lithocarpus species tested in this study. (PDF 1094 kb

  • Molecular genetic and biochemical evidence for adaptive evolution of leaf abaxial epicuticular wax crystals in the genus Lithocarpus (Fagaceae)
    BMC, 2018
    Co-Authors: Chih Kai Yang, Bing Hong Huang, Meng-yuan Huang, Jenn-che Wang, Jian Gao, Pei Chun Liao
    Abstract:

    Abstract Background Leaf epicuticular wax is an important functional trait for physiological regulation and pathogen defense. This study tests how selective pressure may have forced the trait of leaf abaxial epicuticular wax crystals (LAEWC) and whether the presence/absence of LAEWC is associated with other ecophysiological traits. Scanning Electron Microscopy was conducted to check for LAEWC in different Lithocarpus species. Four wax biosynthesis related genes, including two wax backbone genes ECERIFERUM 1 (CER1) and CER3, one regulatory gene CER7 and one transport gene CER5, were cloned and sequenced. Ecophysiological measurements of secondary metabolites, photosynthesis, water usage efficiency, and nutrition indices were also determined. Evolutionary hypotheses of leaf wax character transition associated with the evolution of those ecophysiological traits as well as species evolution were tested by maximum likelihood. Results Eight of 14 studied Lithocarpus species have obvious LAEWC appearing with various types of trichomes. Measurements of ecophysiological traits show no direct correlations with the presence/absence of LAEWC. However, the content of phenolic acids is significantly associated with the gene evolution of the wax biosynthetic backbone gene CER1, which was detected to be positively selected when LAEWC was gained during the late-Miocene-to-Pliocene period. Conclusions Changes of landmass and vegetation type accelerated the diversification of tropical and subtropical forest trees and certain herbivores during the late Miocene. As phenolic acids were long thought to be associated with defense against herbivories, co-occurrence of LAEWC and phenolic acids may suggest that LAEWC might be an adaptive defensive mechanism in Lithocarpus