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Cercospora leaf spot (CLS) disease and bruchids are the common disease and insect pest causing yield loss in mung bean (Vigna radiata (L.) R. Wilczek). ‘KUML4’ is an improved mung bean cultivar grown in Thailand having high yield, early and highly synchronous maturity, large seed size, but susceptible to CLS disease and bruchids. This study was conducted to improve ‘KUML4’ through introgression of VrTAF5 for CLS resistance and VrPGIP2 for bruchid (Callosobruchus maculatus) resistance from landrace mung bean accessions ‘V4718’ and ‘V2808’, respectively, by marker-assisted backcrossing (MABC). In the MABC, foreground selections were performed using VrTAF5- and VrPGIP2-specific markers. The BC3F3 pyramided lines with KUML4 background carrying both VrTAF5 and VrPGIP2 genes were developed and evaluated for agronomic and yield-related traits, CLS resistance, and bruchid resistance. Three BC3F3 lines, KUML4-2020-21, KUML4-2020-23, and KUML4-2020-60, exhibiting superior agronomic and yield-related traits, CLS resistance, and bruchid resistance than ‘KUML4’ were successfully obtained via MABC. Under the CLS outbreak, these lines showed 248.5%-331.7% higher seed yield than ‘KUML4’. The lines expressed nearly perfect resistance to bruchid (< 5% seeds damaged). These lines can be developed into new resistant mung bean cultivars in the future. [ABSTRACT FROM AUTHOR]

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]

Anthocyanins are water-soluble pigments present in several tissues/parts of plants. The pigments provide color and are wildly known for health benefits for human, insect attraction for plant pollination, and stress resistance in plants. Anthocyanin content variations in mungbean [Vigna radiata (L.) Wilczek] were first noticed a long time ago, but the genetic mechanism controlling the anthocyanins in mungbean remains unknown. An F2 population derived from the cross between purple-hypocotyl (V2709) and green-hypocotyl (Sulv1) mungbeans was used to map the VrP locus controlling purple hypocotyl. The VrP locus was mapped to a 78.9-kb region on chromosome 4. Sequence comparison and gene expression analysis identified an R2R3-MYB gene VrMYB90 as the candidate gene for the VrP locus. Haplotype analysis using 124 mungbean accessions suggested that 10 single nucleotide polymorphisms (SNPs) in exon 3 may lead to an abolished expression of VrMYB90 and an absence of anthocyanin accumulation in the hypocotyl of Sulv1 and KPS2. The overexpression of VrMYB90 in mungbean hairy root, tobacco leaf, and Arabidopsis resulted in anthocyanin accumulation (purple color). Gene expression analysis demonstrated that VrMYB90 regulated anthocyanin accumulation in the hypocotyl, stem, petiole, and flowers, and the expression was sensitive to light. VrMYB90 protein may upregulate VrDFR encoding dihydroflavonol 4-reductase at the late biosynthesis step of anthocyanins in mungbeans. These results suggest that VrMYB90 is the dominator in the spatiotemporal regulation of anthocyanin biosynthesis. Our results provide insight into the biosynthesis mechanism of anthocyanin and a theoretical basis for breeding mungbeans. [ABSTRACT FROM AUTHOR]

Black gram (Vigna mungo) is an important short duration grain legume crop. Black gram seeds provide an inexpensive source of dietary protein. Here, we applied the 10X Genomics linked‐read technology to obtain a de novo whole genome assembly of V. mungo cultivated variety Chai Nat 80 (CN80). The preliminary assembly contained 12,228 contigs and had an N50 length of 5.2 Mb. Subsequent scaffolding using the long‐range Chicago and HiC techniques yielded the first high‐quality, chromosome‐level assembly of 499 Mb comprising 11 pseudomolecules. Comparative genomics analyses based on sequence information from single‐copy orthologous genes revealed that black gram and mungbean (Vigna radiata) diverged about 2.7 million years ago. The transversion rate (4DTv) analysis in V. mungo revealed no evidence supporting a recent genome‐wide duplication event observed in the tetraploid créole bean (Vigna reflexo‐pilosa). The proportion of repetitive elements in the black gram genome is slightly lower than the numbers reported for related Vigna species. The majority of long terminal repeat retrotransposons appeared to integrate into the genome within the last five million years. We also examined alternative splicing events in V. mungo using full‐length transcript sequences. While intron retention was the most prevalent mode of alternative splicing in several plant species, alternative 3' acceptor site selection represented the majority of events in black gram. Our high‐quality genome assembly along with the genomic variation information from the germplasm provides valuable resources for accelerating the development of elite varieties through marker‐assisted breeding and for future comparative genomics and phylogenetic studies in legume species. [ABSTRACT FROM AUTHOR]

Summary: Jatropha curcas (physic nut), a non‐edible oilseed crop, represents one of the most promising alternative energy sources due to its high seed oil content, rapid growth and adaptability to various environments. We report ~339 Mbp draft whole genome sequence of J. curcas var. Chai Nat using both the PacBio and Illumina sequencing platforms. We identified and categorized differentially expressed genes related to biosynthesis of lipid and toxic compound among four stages of seed development. Triacylglycerol (TAG), the major component of seed storage oil, is mainly synthesized by phospholipid:diacylglycerol acyltransferase in Jatropha, and continuous high expression of homologs of oleosin over seed development contributes to accumulation of high level of oil in kernels by preventing the breakdown of TAG. A physical cluster of genes for diterpenoid biosynthetic enzymes, including casbene synthases highly responsible for a toxic compound, phorbol ester, in seed cake, was syntenically highly conserved between Jatropha and castor bean. Transcriptomic analysis of female and male flowers revealed the up‐regulation of a dozen family of TFs in female flower. Additionally, we constructed a robust species tree enabling estimation of divergence times among nine Jatropha species and five commercial crops in Malpighiales order. Our results will help researchers and breeders increase energy efficiency of this important oil seed crop by improving yield and oil content, and eliminating toxic compound in seed cake for animal feed. [ABSTRACT FROM AUTHOR]

Traditionally, the quantification of anthocyanin content requires destructive sampling followed by chemical analysis with elaborate process. The aim of this study was to use non-destructive methods for prediction of anthocyanin by using color values from handheld colorimeter. Five hundred and fifty-eight yardlong bean samples that have pale green to dark purple pod color were used for color measurement and anthocyanin analysis. The partial least square regression (PLSR) was used to correlate spectral data with anthocyanin content. The PLSR model could predict anthocyanin content with correlation coefficient of 0.900 and standard error of prediction of 1.994 A/gFw. The results indicated that colorimeter readings can be correlated with anthocyanin content in yardlong bean and could be used as an alternative to chemical analysis. This method is reliable, rapid and inexpensive and can be used to screen a large number of yardlong bean accessions or populations under high anthocyanin breeding program. [ABSTRACT FROM AUTHOR]

Bruchids are stored-grain insect pests responsible for serious seed loss in legume crops. A previous study using an F 2 population (F2OA) derived from a cross between wild moth-bean (Vigna aconitifolia [Jacq.] Maréchal) accession TN67 (resistant) and cultivated moth-bean accession ICPMO056 (susceptible) revealed that resistance to the azuki bean weevil (Callosobruchus chinensis L.) in TN67 was regulated by a single gene located in the major quantitative trait locus— qVacBrc2.1. In this study, qVacBrc2.1 was finely mapped and candidate genes in this locus were identified using F2OA and another large F 2 population (F2NB) derived from the cross mentioned previously. In contrast to the previous study, segregation analysis in the F2NB population revealed that resistance against this pest was controlled by two genes. Furthermore, the addition of novel markers to qVacBrc2.1 and reanalysis of the QTL in the F2OA population demonstrated that qVacBrc2.1 constituted two linked QTLs— qVacBrc2.1-A and qVacBrc2.1-B. The presence of qVacBrc2.1-B was verified using the population F2NB. Comparative genomics using three Vigna spp. strongly suggested the presence of two tandemly duplicated genes, VacPGIP1 and VacPGIP2 , which encoded polygalacturonase inhibitors (polygalacturonase-inhibiting proteins) as the candidates for conferring resistance, but only VacPGIP1 could be successfully cloned and sequenced. The alignment of VacPGIP1 coding sequences of TN67 and ICPMO056 revealed eight single nucleotide polymorphisms, three of which altered the amino-acid sequence of the predicted domains of polygalacturonase inhibitors in ICPMO056. Overall, these findings indicate that VacPGIP1 and VacPGIP2 regulated C. chinensis resistance in TN67. • Fine mapping revealed closely linked genes, VacBrc2.1-A and VacBrc2.1-B , controls C. chinensis resistance in moth bean TN67. • Comparative genome analysis revealed two polygalacturonase-inhibiting protein gene as candidate gene for the resistance. • VacPGIP1 sequence alignment revealed nucleotide polymorphism causing amino acid changes. [ABSTRACT FROM AUTHOR]

Phenotypic and genotypic variability were evaluated in a population of 227 F2 plants derived from an interspecific cross between Jatropha curcas (cv. "Chai Nat") and Jatropha integerrima (local dwarf ornamental type) from Thailand. The objective of this study was to assess the range of variability for 13 phenotypic characters and 16 EST-SSR markers observed in the population. A high variation was found in morphological characters showing many superior genotypes over the J. curcas parent. The results of molecular parameters also suggested a high level of genetic variability in the current population with 100% of polymorphic loci (PPL) for all 16 SSR primers used. The mean numbers of observed alleles (Na) and effective alleles (Ne) were 2.13 and 1.81, respectively. The polymorphic information index (PIC) ranged from 0.17 to 0.55 with an average of 0.34. The average values of Nei's genetic diversity (He), observed heterozygosity (Ho), and Shannon's information index (I) were 0.43, 0.47, and 0.64, respectively. Jaccard's similarity coefficient ranged from 0.51 to 0.96 with a continuous distribution. The UPGMA-based dendrogram could not classify the F2 plants into clusters, but separated them into three sub-groups and seven distinct plants at 61% similarity. The information generated from the current research will be of great benefit to jatropha breeding program; providing a new gene source to the currently low variation in J. curcas. [ABSTRACT FROM AUTHOR]