Search

Powdery mildew (PM) caused by Erysiphe polygoni is an important foliar disease in mungbean (Vigna radiata). A previous study showed that QTL qPMRUM5-2 is a major locus for PM resistance in mungbean accession RUM5 (highly resistant). Bioinformatics analysis revealed that flanking markers of the qPMRUM5-2 covered a region of 1.93 Mb. In this study, we conducted fine mapping for the qPMRUM5-2 using the F2 population of 1156 plants of the cross between Chai Nat 60 (CN60; highly susceptible) and RUM5. PM resistance evaluation was performed under field conditions using F2:3 lines grown in three different environments. QTL analyses consistently located the qPMRUM5-2 to a 0.09 cm interval on linkage group 6 between InDel markers VrLG6-InDel05 and VrLG6-InDel10, which corresponded to a 135.0 kb region on chromosome 8 containing nine predicted genes of which five were NBS-LRR-type genes Recognition of Peronospora parasitica 13-like protein (RPP13L). Whole-genome re-sequencing of RUM5 and CN60 showed polymorphisms in four RPP13L genes predictively cause substantial amino acid changes, rendering them important candidate genes for PM resistance. The InDel markers VrLG6-InDel05 and VrLG6-InDel10 flanking to the qPMRUM5-2 would be useful for marker-assisted breeding of PM resistance in the mungbean. [ABSTRACT FROM AUTHOR]

Jatropha curcas (known as jatropha and physic nut) can be used as an alternative source for biodiesel and biomass production. However, conventional breeding of J. curcas needs time, labor and land for characterization and evaluation of the progenies owing to its perennial growth habit. Quantitative trait loci (QTL) mapping can help identifying marker-trait association and accelerate breeding process of perennial crops through marker-assisted selection. However, the genetic basis for woody biomass improvement in jatropha has not yet been studied. In this manuscript, we report the construction of a SNP-based linkage map and detection of QTLs for woody-biomass-related traits using an F2 population of the interspecific cross between J. curcas and Jatrophaintegerrima. A high-density genetic linkage map containing 2,179 SNPs was constructed. As high as 89.26% of the SNP markers developed from these interspecific progenies expressed significant segregation distortion. Most of the distorted markers showed neither gametophytic nor zygotic selection, except those on linkage groups 3, 5 and 6 which showed gametophytic and zygotic selection. The F2 population showed high variation and transgressive segregation for plant height, canopy width and wood density. QTL analyses detected 5, 8, and 7 loci for plant height, canopy width, and wood density, respectively. The SNPs linked to these QTLs could be incorporated into marker-assisted breeding to maximize the selection gain in jatropha biomass breeding. [ABSTRACT FROM AUTHOR]

Pencil yam (Vigna lanceolata Benth.) (Phaseoleae, Fabaceae) is a herbaceous legume endemic to Australia. A previous morphological study suggested that pencil yam is a complex species of two or more related taxa with seven distinct morphological types (morphotypes) and, thus, taxonomic revision is necessary. In this study, we assessed genetic diversity and determined the genetic structure of a pencil yam collection of 62 accessions from seven morphotypes using 18 microsatellite (simple sequence repeat) markers with the aim to provide information for taxonomic study. In total, 138 alleles were detected with a mean of 7.67 alleles per locus. Polymorphism information content per marker varied between 0.06 and 0.90 with a mean of 0.61, while the overall gene diversity was 0.62. Bayesian clustering, principal coordinate, and neighbor-joining analyses consistently revealed that these accessions are grouped into two subpopulations with difference in number of alleles, allelic richness, and gene diversity. The population structure was not related to either morphotype or geographical origin. Gene diversity of V. lanceolata was higher than that of wild Vigna radiata (L.) Wilczek and wild Vigna umbellata (Thunb.) Ohwi & Ohashi, comparable with that of wild Vigna mungo (L.) Hepper, Vigna exilis Tateishi & Maxted, and Vigna grandiflora (Prain) Tateishi & Maxted, and lower than that of wild Vigna angularis (Willd.) Ohwi & Ohashi. These results indicated that the taxonomy of V. lanceolata should be revised and that its gene diversity was moderate compared with the other wild Vigna species. Key words: Vigna, microsatellite marker, simple sequence repeat, SSR. Vigna lanceolata Benth. (Phaseoleae, Fabaceae) est une legumineuse fourragere endemique de l'Australie. Une etude morphologique anterieure a suggere que V. lanceolata est une espece complexe comprenant au moins deux taxons et sept types morphologiques distincts (morphotypes), ce qui rend necessaire sa revision taxonomique. Dans cette etude, les auteurs ont evalue la diversite genetique et determine la structure genetique d'une collection de V. lanceolata comportant 62 accessions de sept morphotypes a l'aide de 18 marqueurs microsatellites (repetition de sequence simple), dans le but d'obtenir de l'information en vue de l'etude taxonomique. Au total, 138 alleles ont ete detectes, avec une moyenne de 7,67 alleles par locus. Le contenu informationnel du polymorphisme par marqueur variait de 0,06 a 0,90, avec une moyenne de 0,61, alors que la diversite genetique globale etait de 0,62. L'agregation bayesienne, les analyses en coordonnees principales et la methode de NJ ont revele systematiquement que ces accessions sont groupees en deux sous-populations qui different sur le plan du nombre d'alleles, de la richesse allelique et de la diversite genetique. La structure de la population n'etait pas reliee au morphotype ou a l'origine geographique. La diversite genetique de V. lanceolata etait plus grande que celle de Vigna radiata (L.) Wilczek et Vigna umbellata (Thunb.) Ohwi & Ohashi sauvages, comparable a celle de Vigna mungo (L.) Hepper sauvage, Vigna exilis Tateishi & Maxted, et Vigna grandiflora (Prain) Tateishi & Maxted, et plus faible que celle de Vigna angularis (Willd.) Ohwi & Ohashi sauvage. Ces resultats indiquaient que la taxonomie de V. lanceolata devrait etre revisee et que sa diversite genetique etait moderee comparativement a celle d'autres especes de Vigna sauvages. [Traduit par la Redaction] Mots-cles : Vigna, marqueur microsatellite, repetition de sequence simple, SSR., Introduction The genus Vigna (Phaseoleae, Fabaceae) is a large leguminous taxon comprising seven subgenera of 104 herbaceous species distributed in tropical and subtropical regions of Africa, Asia, America, and Australia [...]