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J Baker - One of the best experts on this subject based on the ideXlab platform.
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The spread of resistance to acetolactate synthase inhibiting herbicides in a wind borne, self-pollinated weed species, Lactuca serriola L.
Theoretical and Applied Genetics, 2007Co-Authors: J Baker, C PrestonAbstract:Resistance to ALS-inhibiting herbicides in Lactuca serriola first appeared in the northern Yorke Peninsula in South Australia in 1994, with resistance soon observed at a number of additional sites. The rapid appearance of resistance at many sites could be attributed to a number of independent selection events or to movement of resistant seed from the original field. ISSRs were used to genotype plants collected in 1999 and 2004 from roadsides or fields in an attempt to determine the importance of these two factors in the spread of herbicide resistance in L. serriola . In 1999 and 2004, chlorsulfuron-resistant L. serriola plants were found in both fields and roadsides with resistant plants being more frequent in fields than roadsides and more frequent in 2004 than in 1999. Genetic relationships generated using UPGMA analysis indicated the presence of more than one genotype within the herbicide resistant populations sampled for both years and suggested independent selection as well as movement of resistant seed had occurred. DNA extracted from samples collected in 1999 was used to sequence a highly conserved region of the ALS gene that coded for a single amino acid modification within the gene. Four different mutations were identified within the resistant samples and these mutations tended to cluster on a geographical basis. Together these data provide evidence for both multiple independent evolutionary events and for the potential movement of individual genotypes as far as 43 km in the region.
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multiple effects of a naturally occurring proline to threonine substitution within acetolactate synthase in two herbicide resistant populations of Lactuca serriola
Pesticide Biochemistry and Physiology, 2006Co-Authors: C Preston, Lynley M Stone, M A Rieger, J BakerAbstract:Two populations of Lactuca serriola L. with resistance to acetolactate synthase (ALS)-inhibiting herbicides were discovered in wheat fields at two locations more than 25 km apart in South Australia. Both resistant populations carried a single base change within a highly conserved coding region of the ALS gene that coded for a single amino acid modification within ALS. The modification of proline 197 to threonine resulted in an enzyme that was highly resistant (>200-fold) to inhibition by sulfonylurea herbicides and moderately resistant to triazolopyrimidine and imidazolinone herbicides. The herbicide-resistant ALS was also less sensitive to inhibition by the branched-chain amino acids valine and leucine. In addition, the resistant enzyme had a lower Km for pyruvate. However, extractable ALS activity was similar between resistant and susceptible plants. The substitution of threonine for proline 197 within ALS has multiple impacts on ALS enzyme activity in L. serriola that may influence the frequency of this resistant allele in the environment.
Mithila Jayasundera - One of the best experts on this subject based on the ideXlab platform.
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environmental factors affecting the germination and seedling emergence of two populations of an emerging agricultural weed wild lettuce Lactuca serriola
Crop & Pasture Science, 2019Co-Authors: Aakansha Chadha, Singarayer Florentine, Bhagirath S Chauhan, Benjamin M Long, Mithila Jayasundera, Muhammad Mansoor Javaid, Christopher TurvilleAbstract:Wild lettuce (Lactuca serriola L.) is a significant emerging agricultural and environmental weed in many countries. This invasive species is now naturalised in Australia and is claimed to cause significant losses within the agricultural industry. Sustainable management of wild lettuce has been hampered by a lack of detailed knowledge of its seed ecology. Laboratory-based studies were performed to examine the potential influence of environmental factors including temperature and light conditions, salinity, pH, moisture availability and burial depth on the germination and emergence of two spatially distant populations of wild lettuce. Results suggested that the germination of wild lettuce seeds occurred across a broad range of temperature conditions (12-h cycle: 30°C/20°C, 25°C/15°C and 17°C/7°C) for both populations. We also found that these seeds are non-photoblastic; germination was not affected by darkness, with >80% germination in darkness for both populations at all tested temperature ranges. Germination significantly declined as salinity and osmotic stress increased for both populations, with seeds from the Tempy population were more affected by NaCl >100 mM than seeds from Werribee, but in neither population was there any observed effect of pH on germination (>80% germination in both populations at all tested pH ranges). For both populations, germination significantly decreased as burial depth increased; however, the two populations differed with regard to response to burial depth treatment, whereby seeds from the Tempy population had higher emergence than those from Werribee at 0.5 cm burial depth. These results suggest that light-reducing management techniques such as mulching or use of crop residues will be unsuccessful for preventing germination of wild lettuce. By contrast, burial of seeds at a depth of at least 4 cm will significantly reduce their emergence.
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influence of soil moisture regimes on growth photosynthetic capacity leaf biochemistry and reproductive capabilities of the invasive agronomic weed Lactuca serriola
PLOS ONE, 2019Co-Authors: Aakansha Chadha, Singarayer Florentine, Bhagirath S Chauhan, Benjamin M Long, Mithila JayasunderaAbstract:Global temperatures are predicted to increase by 1.5-5.9°C during this century, and this change is likely to impact average rainfall, with predictions that water deficit will perhaps be the most severe threat to sustainable agriculture. In this respect, invasive weeds, which have traits better adapted to drought stress than crops, add to concerns regarding crop sustainability. Lactuca serriola, an aggressive agronomic weed is thought to be a successful weed because of its ability to maintain high water use efficiency under drought conditions. In this study, experiments were conducted to examine the influence of different soil moisture regimes (100%, 75%, 50% and 25% water holding capacity (WHC)) on growth, photosynthetic capacity, leaf biochemistry and reproduction of this species. Soil moisture significantly affected plant's height, stem diameter, number of leaves and biomass. The highest plant height (115.14 cm ± 11.64), shoot diameter (9.4 mm ± 0.18), leaf area (1206.5 mm2 ± 73.29), plant fresh weight (83.1 ± 3.98) and dry weight (22.38 ± 1.24) were recorded at 75% soil moisture content. A fundamental adaptation to drought was observed as plants in the 25% WHC treatment had the highest root: shoot ratio. Soluble sugars and total phenolic content were highest in the 25% WHC treatment and significantly different to 100% WHC which was a response to soil moisture stress to ameliorate the damaging effects of reactive oxygen species produced under stress conditions. Results also indicate that L. serriola can survive and produce seeds under water stress as more than 6000 seeds were produced per plant in all WHC treatments. In this study, there was no significant difference in the seed weight, number of seeds produced and their germination ability. This can have a huge impact on agricultural systems as the species can survive both under low and high soil moisture conditions. We therefore suggest that the demonstrated ability of L. serriola to complete its life cycle and produce biomass and seeds under water stressed conditions leads to the introduction of strategies that minimize weed survival while maximizing irrigation efficiency for the crop. A clear understanding of the ecological and biological characteristics of this weed will help land managers take appropriate control measures to mitigate the effect of this species on economic crop productivity.
C Preston - One of the best experts on this subject based on the ideXlab platform.
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The spread of resistance to acetolactate synthase inhibiting herbicides in a wind borne, self-pollinated weed species, Lactuca serriola L.
Theoretical and Applied Genetics, 2007Co-Authors: J Baker, C PrestonAbstract:Resistance to ALS-inhibiting herbicides in Lactuca serriola first appeared in the northern Yorke Peninsula in South Australia in 1994, with resistance soon observed at a number of additional sites. The rapid appearance of resistance at many sites could be attributed to a number of independent selection events or to movement of resistant seed from the original field. ISSRs were used to genotype plants collected in 1999 and 2004 from roadsides or fields in an attempt to determine the importance of these two factors in the spread of herbicide resistance in L. serriola . In 1999 and 2004, chlorsulfuron-resistant L. serriola plants were found in both fields and roadsides with resistant plants being more frequent in fields than roadsides and more frequent in 2004 than in 1999. Genetic relationships generated using UPGMA analysis indicated the presence of more than one genotype within the herbicide resistant populations sampled for both years and suggested independent selection as well as movement of resistant seed had occurred. DNA extracted from samples collected in 1999 was used to sequence a highly conserved region of the ALS gene that coded for a single amino acid modification within the gene. Four different mutations were identified within the resistant samples and these mutations tended to cluster on a geographical basis. Together these data provide evidence for both multiple independent evolutionary events and for the potential movement of individual genotypes as far as 43 km in the region.
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multiple effects of a naturally occurring proline to threonine substitution within acetolactate synthase in two herbicide resistant populations of Lactuca serriola
Pesticide Biochemistry and Physiology, 2006Co-Authors: C Preston, Lynley M Stone, M A Rieger, J BakerAbstract:Two populations of Lactuca serriola L. with resistance to acetolactate synthase (ALS)-inhibiting herbicides were discovered in wheat fields at two locations more than 25 km apart in South Australia. Both resistant populations carried a single base change within a highly conserved coding region of the ALS gene that coded for a single amino acid modification within ALS. The modification of proline 197 to threonine resulted in an enzyme that was highly resistant (>200-fold) to inhibition by sulfonylurea herbicides and moderately resistant to triazolopyrimidine and imidazolinone herbicides. The herbicide-resistant ALS was also less sensitive to inhibition by the branched-chain amino acids valine and leucine. In addition, the resistant enzyme had a lower Km for pyruvate. However, extractable ALS activity was similar between resistant and susceptible plants. The substitution of threonine for proline 197 within ALS has multiple impacts on ALS enzyme activity in L. serriola that may influence the frequency of this resistant allele in the environment.
Ian C. Burke - One of the best experts on this subject based on the ideXlab platform.
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Genetic and Biochemical Evaluation of Natural Rubber from Eastern Washington Prickly Lettuce (Lactuca serriola L.)
Journal of agricultural and food chemistry, 2015Co-Authors: Jared L. Bell, Ian C. Burke, Michael M NeffAbstract:Alternative sources of natural rubber are of importance due to economic, biological, and political threats that could diminish supplies of this resource. Prickly lettuce (Lactuca serriola L.) synthesizes long-chain natural rubber and was studied to determine underlying genetic and phenotypic characteristics of rubber biosynthesis. Genotypic and phenotypic analysis of an F2 segregating population using EST-SSR markers led to the discovery of genetic regions linked to natural rubber production. Interval mapping (IM) and multiple QTL mapping (MQM) identified several QTL in the mapping population that had significance based on LOD score thresholds. The discovered QTL and the corresponding local markers are genetic resources for understanding rubber biosynthesis in prickly lettuce and could be used in marker-assisted selection (MAS) breeding. Prickly lettuce is an excellent candidate for elucidating the rubber synthesis mechanism and has potential as a crop plant for rubber production.
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inheritance and physiological basis for 2 4 d resistance in prickly lettuce Lactuca serriola l
Journal of Agricultural and Food Chemistry, 2011Co-Authors: Dilpreet S Riar, Jared L. Bell, Ian C. Burke, Joseph P Yenish, Kulvinder S GillAbstract:Experiments were conducted to determine the inheritance and physiological basis for resistance to the synthetic auxinic herbicide (2,4-dichlorophenoxy)acetic acid (2,4-D) in a prickly lettuce biotype. Inheritance of 2,4-D resistance in prickly lettuce is governed by a single codominant gene. Absorption and translocation were conducted using 14C-2,4-D applied to 2,4-D-resistant and -susceptible biotypes. At 96 h after treatment (HAT), the resistant biotype absorbed less applied 2,4-D and retained more 2,4-D in the treated portion of the leaf compared to the susceptible biotype. The resistant biotype translocated less applied 2,4-D to leaves above the treated leaf and crown at 96 HAT compared to the susceptible biotype. No difference in the rate of metabolism of 2,4-D was observed between the two biotypes. Resistance to 2,4-D appears to originate from a reduced growth deregulatory and overstimulation response compared to the susceptible biotype, resulting in lower translocation of 2,4-D in the resistant pri...
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resistance of a prickly lettuce Lactuca serriola biotype to 2 4 d
Weed Technology, 2009Co-Authors: Ian C. Burke, Joseph P Yenish, Dennis Pittmann, Robert S GallagherAbstract:Abstract Dose-response experiments were conducted on a biotype of prickly lettuce collected from Whitman County, WA, to determine the level of resistance to 2,4-D. Initially, progeny of prickly lettuce that survived two applications of glyphosate and 2,4-D in mixture were collected to determine if antagonism of the 2,4-D or glyphosate was occurring. Prickly lettuce survival was determined to not be due to antagonism of 2,4-D or glyphosate when the two herbicides were applied in mixture. The doses required to reduce growth 50% (GR50) for resistant and susceptible field-collected prickly lettuce were 150 and 6 g ae/ha 2,4-D, respectively, indicating the resistant biotype was 25 times more resistant to 2,4-D than the susceptible biotype. The resistant biotype expressed injury but produced regrowth following application. A dose of 2,4-D at 220 g/ha was required to reduce regrowth frequency 50% (FR50) for resistant field-collected prickly lettuce. Regrowth was also observed with the susceptible biotype, althou...
A. Lebeda - One of the best experts on this subject based on the ideXlab platform.
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leveillula Lactucae serriolae on Lactuca serriola in jordan
Phytopathologia Mediterranea, 2019Co-Authors: A. Lebeda, Miloslav Kitner, B Mieslerova, Eva Křistkova, Tomas PavlicekAbstract:Jordan contributes significantly to the Near East plant biodiversity with numerous primitive forms and species of crops and their wild relatives. Prickly lettuce (Lactuca serriola) is a common species in Jordan, where it grows in various habitats. During a survey of wild Lactuca distribution in Jordan in August 2007, plants of L. serriola with natural infections of powdery mildew were observed at a site near Shobak (Ma’an Governorate). Lactuca serriola leaf samples with powdery mildew infections were collected from two plants and the pathogen was analyzed morphologically. Characteristics of the asexual and sexual forms were obtained. Sequence analyses of the rDNA ITS region and D1/D2 domains of the 28S rDNA were used to obtain phylogenetic data, and to reach taxonomic conclusions about these specimens. Molecular determination, performed by sequencing of the ITS region, proved its identity with the type material of Leveillula Lactucae-serriolae. Sequencing of the 28S rDNA region provided the first verified GenBank record of Leveillula Lactucae-serriolae deposited in this public nucleotide repository. This is the first taxonomically verified record of L. Lactucae-serriolae on L. serriola growing wild in Jordan, and one of the first records of the fungus in the Near East.
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genetic variability and distance between Lactuca serriola l populations from sweden and slovenia assessed by ssr and aflp markers
Acta Botanica Croatica, 2018Co-Authors: Michaela Jemelkova, Eva Křistkova, Miloslav Kitner, Ivana Doležalova, A. LebedaAbstract:The study involved 121 samples of the common weed, Lactuca serriola L. (prickly lettuce), representing 53 populations from Sweden and Slovenia. The seed materials, originating from different habitats, were regenerated and taxonomically validated at the Department of Botany, Palacký University in Olomouc, Czech Republic. The morphological characterizations of the collected plant materials classified all 121 samples as L. serriola f. serriola; one sample was heterogeneous, and also present was L. serriola f. integrifolia. Differences in the amount and distribution of the genetic variations between the two regions were analyzed using 257 amplified fragment length polymorphism (AFLP) and 7 microsatellite (SSRs) markers. Bayesian clustering and Neighbor-Network were used for visualization of the differences among the samples by country. Under the Bayesian approach, the best partitioning (according to the most frequent signals) was resolved into three groups. While the absence of an admixture or low admixture was detected in the Slovenian samples, and the majority of the Swedish samples, a significant admixture was detected in the profiles of five Swedish samples collected near Malmo, which bore unique morphological features of their rosette leaves. The Neighbor-Network analysis divided the samples into 6 groups, each consisting of samples coming from a particular country. Reflection of morphology and eco-geographical conditions in genetic variation are also discussed.
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morphological variation of Lactuca serriola l achenes as a function of their geographic origin
Acta Botanica Croatica, 2014Co-Authors: Eva Křistkova, A. Lebeda, Alžběta Novotna, Ivana Doležalova, Tomas BerkaAbstract:The morphological characteristics of achenes of Lactuca serriola represented by 34 local populations from Slovenia and 12 local populations from Sweden were studied in relation to their eco- geographical conditions. In total, eight quantitative morphological characters were evaluated: length and width of achene body; index length/width of achene body; number of ribs on achene body; length of beak; length of pappus bristles; pappus area and discus diameter. Nested ANOVA analysis indicated significant differences in length and width of achene body, length of pappus bristles, and pappus area between Slovenian and Swedish populations. Achenes from Slovenia were longer, wider and possessed longer pappus bristles than achenes from Sweden. Among geographical factors, latitude had the greatest impact on the morphological characters evaluated. Significant differences in seven parameters were also found between populations within countries and between samples within populations. It is probable that this variation has a genetic basis with sufficient variation within populations to permit continued selection.
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host specificity and virulence variation in populations of lettuce powdery mildew pathogen golovinomyces cichoracearum s str from prickly lettuce Lactuca serriola
Mycological Progress, 2013Co-Authors: A. Lebeda, I. Petrželová, B Mieslerova, P KorbelovaAbstract:Fifty-four isolates of Golovinomyces cichoracearum (GC) sensu stricto were collected during the period 2008–2010 from natural populations of prickly lettuce (Lactuca serriola) growing in the Czech Republic. Population variation in virulence was assessed with a previously developed race differential set, comprising 13 accessions of four Lactuca species (L. serriola, L. sativa, L. saligna, L. virosa, and L. sativa ‘Hilde’ × L. serriola hybrid). GC isolates differed in their host specificity and virulence; most were able to infect most Lactuca spp. accessions (i.e., complete compatibility), but some showed only moderate virulence (i.e., incomplete compatibility). ‘Avirulent’ reactions were the least common, and these were most frequently observed on L. virosa (LVIR/50) and L. saligna (09-H58-1013). Furthermore, a temporal shift in virulence variability was recorded for the Czech GC populations. Generally, virulence of GC to the Lactuca spp. accessions increased during the study period. Across individual years, the most variable were reactions of GC to L. serriola accession (PI 273617), L. sativa cv. ‘Colorado’, L. saligna (09-H58-1013) and L. virosa (LVIR/50). A broad spectrum of virulence (v)-phenotypes was determined among the 54 isolates; however, differences in the reaction patterns of individual isolates were mostly small and related to differentiation between moderately and completely compatible interactions. However, most of the v-phenotypes characterized were unique to a given population in one year. Altogether, 16 v-phenotypes were identified among 16 isolates tested in 2008, 10 v-phenotypes were determined among 10 isolates tested in 2009, and 24 v-phenotypes among 28 isolates tested in 2010; i.e., different v-phenotypes were identified in different localities.
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morphological variability of achenes of some european populations of Lactuca serriola l
Flora, 2011Co-Authors: Alžběta Novotna, A. Lebeda, Ivana Doležalova, Milena Krskova, Tomas BerkaAbstract:Abstract This study focuses on the morphological variability of Lactuca serriola achenes in relation to eco-geographic features. Fifty L. serriola populations from four European countries, Czech Republic, Germany, the Netherlands and United Kingdom, were studied. Five morphological characters of the achenes – length and width of achene, length/width index, length of beak, and number of ribs – were evaluated. Significant differences exist in achene morphology of two leaf forms of L. serriola, forma serriola and forma integrifolia. Achenes of f. serriola are shorter, thinner, shorter beaked, lower length/width index, and higher number of ribs compared to f. integrifolia. There was significant variation in the measured characters. Statistical analysis indicated that achene length and width increased along an east–west transect from 2.95 to 3.35 mm and 0.93 to 1.00 mm, respectively. Mean beak length had a similar trend with the exception of German achenes. They had shorter beaks than achenes originating from the Czech Republic with 4.38 and Germany with 4.33 mm. The same trend was evident for L/W index from Czech with a ratio of 3.21 and Germany with 3.14. The number of ribs increased from east to the west in continental Europe, whereas the lowest number of ribs was recorded in achenes collected in Czech with 10.89 and the UK with 10.59. Achene morphology was significantly correlated with three eco-geographic features; longitude, latitude, soil texture of the habitats. The other eco-geographic factors, altitude and population size, did not significantly correlate with the studied characters of L. serriola achenes.
