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R G Shivas - One of the best experts on this subject based on the ideXlab platform.
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evaluation of ustilago sporoboli indici as a classical biological control agent for invasive Sporobolus grasses in australia
Biological Control, 2009Co-Authors: K S Yobo, Mark Laing, W A Palmer, R G ShivasAbstract:Sporobolus pyramidalis, S. africanus, S. natalensis, S. fertilis and S. jacquemontii, known collectively as the weedy Sporobolus grasses, are exotic weeds causing serious economic losses in grazing areas along Australia's entire eastern coast. In one of the first attempts to provide biological control for a grass, the potential of a smut, Ustilago sporoboli-indici, as a biological control agent for all five weedy Sporobolus spp. found in Australia was evaluated in glasshouse studies. Application of basidiospores to 21-day-old Sporobolus seedlings and subsequent incubation in a moist chamber (26 °C, 90% RH, 48 h) resulted in infection of S. pyramidalis, S. africanus, S. natalensis and S. fertilis but not S. jacquemontii. Host-range trials with 13 native Australian Sporobolus spp. resulted in infection of four native species. Evaluation of damage caused by the smut on two Australian native and two weedy Sporobolus spp. showed that the total numbers of flowers infected for the four grasses were in the following order: S. creber > S. fertilis > S. elongatus > S. natalensis with percentage flower infections of 21%, 14%, 12% and 3%, respectively. Significant differences (P = 0.001) were found when the numbers of infected flowers caused by each treatment were compared. The infection of the four native Sporobolus spp. by the smut indicated that it was not sufficiently host specific for release in Australia and the organism was rejected as a potential biological control agent. The implications of these results are discussed.
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phylogenetic considerations for predicting the host range of ustilago sporoboli indici a potential biological control agent for Sporobolus species in australia
2006Co-Authors: J H Cunnington, R G ShivasAbstract:The ribosomal DNA internal transcribed spacer region was amplified and sequenced from a selection of specimens of the Sporobolus smut Ustilago sporoboli-indici. Phylogenetic comparison with other Ustilago and Sporisorium species revealed strong support for an evolutionary radiation of Ustilago species infecting the Chloridoideae and Pooideae, of which U. sporoboli-indici forms a major lineage. Comparisons are made with other groups of plant pathogenic fungi, and it is concluded that phylogenetic analyses of potential biocontrol agents are useful for identifying pathogens that are derived from evolutionary lineages that parasitize a wide range of unrelated plants. Such pathogens are less desirable as biocontrol agents as they may have a greater likelihood of infecting plants outside their normal host ranges.
Melvin J Oliver - One of the best experts on this subject based on the ideXlab platform.
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biomass production nutritional and mineral content of desiccation sensitive and desiccation tolerant species of Sporobolus under multiple irrigation regimes
Journal of Agronomy and Crop Science, 2013Co-Authors: Abou Yobi, Karen Schlauch, Barry L Perryman, Melvin J Oliver, John C CushmanAbstract:The development of low-water-input forages would be useful for improving the water-use efficiency of livestock production in semi-arid and arid regions. The desiccation-tolerant (DT) species Sporobolus stapfianus Gandoger and two desiccation-sensitive (DS) species, Sporobolus pyramidalis and Sporobolus fimbriatus (Trin.) Nees. (Poaceae), were evaluated for aerial biomass production and seed productivity under three different irrigation regimes. Sporobolus stapfianus displayed the least biomass production, whereas S. pyramidalis and S. fimbriatus produced up to 3.8and 11.2-fold greater dry biomass, respectively, at the highest irrigation rate of 12 334 l (0.01 acre-feet). Sporobolus fimbriatus and to a lesser extent S. pyramidalis showed significant increases in biomass production in response to increased irrigation rates, whereas S. stapfianus did not. Sporobolus pyramidalis and S. fimbriatus exhibited 3.2and 6.0-fold greater seed production, respectively, in response to increased irrigation rates, whereas S. stapfianus showed only a 1.4-fold increase. All Sporobolus species possessed forage quality traits (e.g. crude protein, fibre content) comparable to those of timothy, a forage grass grown widely in the Great Basin in the western United States. Micronutrient content exceeded the minimum requirements of beef cattle, without surpassing tolerable limits, with the exception of zinc, which appeared low in all three Sporobolus species. The low water requirements displayed by these species, combined with their acceptable forage qualities, indicate that these grasses have the potential to serve farmers and ranchers in semi-arid and arid regions of the western United States where irrigation resources are limited.
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Biomass Production, Nutritional and Mineral Content of Desiccation‐Sensitive and Desiccation‐Tolerant Species of Sporobolus under Multiple Irrigation Regimes
Journal of Agronomy and Crop Science, 2013Co-Authors: Abou Yobi, Karen Schlauch, Barry L Perryman, Melvin J Oliver, John C CushmanAbstract:The development of low-water-input forages would be useful for improving the water-use efficiency of livestock production in semi-arid and arid regions. The desiccation-tolerant (DT) species Sporobolus stapfianus Gandoger and two desiccation-sensitive (DS) species, Sporobolus pyramidalis and Sporobolus fimbriatus (Trin.) Nees. (Poaceae), were evaluated for aerial biomass production and seed productivity under three different irrigation regimes. Sporobolus stapfianus displayed the least biomass production, whereas S. pyramidalis and S. fimbriatus produced up to 3.8and 11.2-fold greater dry biomass, respectively, at the highest irrigation rate of 12 334 l (0.01 acre-feet). Sporobolus fimbriatus and to a lesser extent S. pyramidalis showed significant increases in biomass production in response to increased irrigation rates, whereas S. stapfianus did not. Sporobolus pyramidalis and S. fimbriatus exhibited 3.2and 6.0-fold greater seed production, respectively, in response to increased irrigation rates, whereas S. stapfianus showed only a 1.4-fold increase. All Sporobolus species possessed forage quality traits (e.g. crude protein, fibre content) comparable to those of timothy, a forage grass grown widely in the Great Basin in the western United States. Micronutrient content exceeded the minimum requirements of beef cattle, without surpassing tolerable limits, with the exception of zinc, which appeared low in all three Sporobolus species. The low water requirements displayed by these species, combined with their acceptable forage qualities, indicate that these grasses have the potential to serve farmers and ranchers in semi-arid and arid regions of the western United States where irrigation resources are limited.
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a sister group contrast using untargeted global metabolomic analysis delineates the biochemical regulation underlying desiccation tolerance in Sporobolus stapfianus
The Plant Cell, 2011Co-Authors: Melvin J Oliver, Lining Guo, Danny Alexander, John A Ryals, Bernard W M Wone, John C CushmanAbstract:Understanding how plants tolerate dehydration is a prerequisite for developing novel strategies for improving drought tolerance. The desiccation-tolerant (DT) Sporobolus stapfianus and the desiccation-sensitive (DS) Sporobolus pyramidalis formed a sister group contrast to reveal adaptive metabolic responses to dehydration using untargeted global metabolomic analysis. Young leaves from both grasses at full hydration or at 60% relative water content (RWC) and from S. stapfianus at lower RWCs were analyzed using liquid and gas chromatography linked to mass spectrometry or tandem mass spectrometry. Comparison of the two species in the fully hydrated state revealed intrinsic differences between the two metabolomes. S. stapfianus had higher concentrations of osmolytes, lower concentrations of metabolites associated with energy metabolism, and higher concentrations of nitrogen metabolites, suggesting that it is primed metabolically for dehydration stress. Further reduction of the leaf RWC to 60% instigated a metabolic shift in S. stapfianus toward the production of protective compounds, whereas S. pyramidalis responded differently. The metabolomes of S. stapfianus leaves below 40% RWC were strongly directed toward antioxidant production, nitrogen remobilization, ammonia detoxification, and soluble sugar production. Collectively, the metabolic profiles obtained uncovered a cascade of biochemical regulation strategies critical to the survival of S. stapfianus under desiccation.
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characterization of a desiccation responsive small gtp binding protein rab2 from the desiccation tolerant grass Sporobolus stapfianus
Plant Molecular Biology, 1999Co-Authors: Patrick J Omahony, Melvin J OliverAbstract:We have used differential display to detect altering mRNA levels in response to desiccation and rehydration in leaves of the desiccation tolerant grass Sporobolus stapfianus. One of the RT-PCR products identified was used to isolate a cDNA of 999 bp which encodes a protein of 210 amino acids (predicted size 23 kDa). This protein displays considerable sequence similarity to mammalian and plant Rab2, a small GTP-binding protein, possessing several conserved motifs common to these regulatory proteins. Sporobolus Rab2 was expressed in Escherichia coli yielding a protein with an apparent molecular mass of ca. 30 kDa which was shown to have the ability to bind GTP. Rab2 transcript accumulated early in response to a decrease in relative water content (RWC) and remained high even in dried leaves. Rehydration of desiccated leaves resulted in a decrease in levels within 3 h of rewetting, with a brief increase at ca. 12 h. Accumulation of Rab2 transcript was also evident during drying and rehydration of the roots of S. stapfianus, as well as in leaves of the desiccation-sensitive grass Sporobolus pyramidalis. Earlier work on S. stapfianus concluded that the plant hormone ABA has little effect on inducing desiccation tolerance, however Rab2 transcript does exhibit a small increase in accumulation in response to exogenous ABA. A possible role for Rab2 with respect to desiccation tolerance and damage repair is discussed.
K S Yobo - One of the best experts on this subject based on the ideXlab platform.
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evaluation of ustilago sporoboli indici as a classical biological control agent for invasive Sporobolus grasses in australia
Biological Control, 2009Co-Authors: K S Yobo, Mark Laing, W A Palmer, R G ShivasAbstract:Sporobolus pyramidalis, S. africanus, S. natalensis, S. fertilis and S. jacquemontii, known collectively as the weedy Sporobolus grasses, are exotic weeds causing serious economic losses in grazing areas along Australia's entire eastern coast. In one of the first attempts to provide biological control for a grass, the potential of a smut, Ustilago sporoboli-indici, as a biological control agent for all five weedy Sporobolus spp. found in Australia was evaluated in glasshouse studies. Application of basidiospores to 21-day-old Sporobolus seedlings and subsequent incubation in a moist chamber (26 °C, 90% RH, 48 h) resulted in infection of S. pyramidalis, S. africanus, S. natalensis and S. fertilis but not S. jacquemontii. Host-range trials with 13 native Australian Sporobolus spp. resulted in infection of four native species. Evaluation of damage caused by the smut on two Australian native and two weedy Sporobolus spp. showed that the total numbers of flowers infected for the four grasses were in the following order: S. creber > S. fertilis > S. elongatus > S. natalensis with percentage flower infections of 21%, 14%, 12% and 3%, respectively. Significant differences (P = 0.001) were found when the numbers of infected flowers caused by each treatment were compared. The infection of the four native Sporobolus spp. by the smut indicated that it was not sufficiently host specific for release in Australia and the organism was rejected as a potential biological control agent. The implications of these results are discussed.
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prospects for the biological control of the weedy Sporobolus grasses in australia
Proceedings of the 16th Australian Weeds Conference Cairns Convention Centre North Queensland Australia 18-22 May 2008., 2008Co-Authors: W A Palmer, K S Yobo, A B R WittAbstract:Bill Palmer and colleagues recently published their paper 'Prospects for the biological control of the weedy Sporobolus grasses in Australia' in Proceedings of the 16th Australian Weeds Conference. The paper gives a summary of a recent project to find a biological control for the weedy Sporobolus grasses, which include giant rat's tail grass. Southern Africa was surveyed for potential agents and two, a leaf smut and a stem wasp, were selected for follow up studies. Unfortunately, they could not rear the stem wasp in the laboratory and the leaf smut infected four of the Australian native Sporobolus spp. and was therefore rejected. This project was one of the first attempts at biological control of a grass.
Jeffery M. Saarela - One of the best experts on this subject based on the ideXlab platform.
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NEW COMBINATIONS IN Sporobolus (POACEAE: CHLORIDOIDEAE)
2020Co-Authors: Paul M. Peterson, Jeffery M. Saarela, Botany Section, Konstantin RomaschenkoAbstract:The following four new combinations are made: Sporobolus borszczowii (Regel) P.M. Peterson, Sporobolus borszczowii subsp. acuminatus (Trin.) P.M. Peterson, Sporobolus borszczowii subsp. ambiguus (Boiss. & Balansa ex Boiss.) P.M. Peterson, and Sporobolus montevidensis (Arechav.) P.M. Peterson & Saarela.
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a molecular phylogeny and new subgeneric classification of Sporobolus poaceae chloridoideae sporobolinae
Taxon, 2014Co-Authors: Paul M. Peterson, Konstantin Romaschenko, Yolanda Herrera Arrieta, Jeffery M. SaarelaAbstract:The grass subtribe Sporobolinae contains six genera: Calamovilfa (5 spp. endemic to North America), Crypsis (10 spp. endemic to Asia and Africa), Psilolemma (1 sp. endemic to Africa), Spartina (17 spp. centered in North America), Sporobolus (186 spp. distributed worldwide), and Thellungia (1 sp. endemic to Australia). Most species in this subtribe have spikelets with a single floret, 1-veined (occasionally 3 or more) lemmas, a ciliate membrane or line of hairs for a ligule, and fruits with free pericarps (modified caryopses). Phylogenetic analyses were conducted on 177 species (281 samples), of which 145 species were in the Sporobo - linae, using sequence data from four plastid regions (rpl32-trnL spacer, ndhA intron, rps16-trnK spacer, rps16 intron) and the nuclear ribosomal internal transcribed spacer regions (ITS) to infer evolutionary relationships and provide an evolutionary framework on which to revise the classification. The phylogenetic analysis provides weak to moderate support for a paraphyletic Sporobolus that includes Calamovilfa, Crypsis, Spartina, and Thellungia. In the combined plastid tree, Psilolemma jaegeri is sister to a trichotomy that includes an unsupported Urochondra-Zoysia clade (subtr. Zoysiinae), a strongly supported Sporobolus somalensis lineage, and a weakly supported Sporobolus s.l. lineage. In the ITS tree the Zoysiinae is sister to a highly supported Sporobolinae in which a Psilolemma jaegeri-Sporobolus somalensis clade is sister to the remaining species of Sporobolus s.l. Within Sporobolus s.l. the nuclear and plastid analyses identify the same 16 major clades of which 11 are strongly supported in the ITS tree and 12 are strongly supported in the combined plastid tree. The positions of three of these clades representing proposed sections Crypsis, Fimbriatae, and Triachyrum are discordant in the nuclear and plastid trees, indicating their origins may involve hybridization. Seven species fall outside the major clades in both trees, and the placement of ten species of Sporobolus are discordant in the nuclear and plastid trees. We propose incorporating Calamovilfa, Crypsis, Spartina, Thellungia, and Eragrostis megalosperma within Sporobolus, and make the requisite 35 new combinations or new names. The molecular results support the recognition of 11 sections and 11 subsections
Sandra S Aliscioni - One of the best experts on this subject based on the ideXlab platform.
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el complejo Sporobolus indicus poaceae chloridoideae zoysieae en la argentina
Darwiniana, 2011Co-Authors: Silvia S Denham, Sandra S AliscioniAbstract:Denham, S. S. & S. S. Aliscioni. 2011. The Sporobolus indicus (Poaceae, Chloridoideae, Zoysieae) com- The species in the Sporobolus indicus complex are analyzed for Argentina. Sporobolus indicus var. indicus and S. indicus var. andinus are recognized for Argentina based on significant value differences in culms height and inflorescence length, and the altitude of collection area. The var. andinus is a new record for the Argentinean flora and it is here illustrated. Sporobolus jacquemontii is excluded from Argentina and S. minor is considered as a synonymy of S. indicus var. indicus.
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species delimitation in the Sporobolus aeneus complex zoysieae chloridoideae poaceae using the phylogenetic species concept
Taxon, 2010Co-Authors: Silvia S Denham, Sandra S AliscioniAbstract:The "Sporobolus aeneus complex" constitutes a morphologically well-defined group of species with lax, exerted, pyramidal panicles with verticillate branches, and comprises 14 species and six infraspecific taxa in southern South America (eastern Bolivia, eastern Paraguay, Uruguay, southern Brazil, northeastern Argentina). Species delimitation in the complex remains unresolved. To clarify the taxonomy of the group, multivariate analyses of qualitative and quantitative characters from herbaria specimens were performed. We applied the phylogenetic species concept and we used a modified "population aggregation analysis." Five species (S. aeneus, S. cubensis, S. linearifolius, S. multinodis, S. recurvatus) are recognized by unique combinations of qualitative character states, and three varieties based on significant mean value differences of quantitative characters. We conclude that leaf blade pilosity, widely used as a diagnostic character in the complex, is affected by external conditions like fire or blade age and is taxonomically unreliable. Two new cominations, Sporobolus aeneus var. angustifolia (Doll) S. Denham & Aliscioni and S. aeneus var. eximius (Nees ex Trin.) S. Denham & Aliscioni are made. Vilfa acuminata Trin. and Vilfa eximia Nees ex Trin. are lectotypified.
