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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]

Mungbean [Vigna radiata (L.) R. Wilczek] is an agro‐economically important legume crop of Thailand. In recent years, mungbean has been gaining attention and popularity from consumers and industries for its dense nutrients. Although farmers, consumers, and processors prefer large‐seeded mungbeans, all mungbean cultivars available in Thailand are medium‐seeded. Therefore, a need was felt to develop new mungbean cultivars with large seed size that would fulfill the needs of farmers, consumers, and processors. In this study, we report the development of two new mungbean cultivars: 'KUML4' (Reg. no. CV‐354, PI 703288) and 'KUML8' (Reg. no. CV‐355, PI 703289). These cultivars were developed by pedigree and bulk‐selection methods. Standard yield trials revealed that KUML4 gave seed yields (SDY) of 1444.75 and 1316.38 kg ha−1, respectively, which was on par with check cultivars. The seed of KUML4 and KUML8 was larger than all of the check cultivars; their 100‐seed weights were 7.25 and 7.84 g, respectively, compared with 6.58 g, the mean of the check cultivars. Further, the genotype main effect plus genotype‐by‐environment analysis showed that KUML4 had good yield stability for its SDY. The yield trials under farmer fields and practices revealed that KUML4 gave SDY similar to the best check cultivar, 'Chai Nat 3' (CN3), whereas KUML8 gave a lower yield than CN3. The yield gap between the experimental research station and farmer field/practice was about 47%. In conclusion, KUML4 and KUML8 have shown high yield, large seed size, and early and uniform maturity. Core Ideas: Two mungbean cultivars with large seeds and high yield stability were developed for Thailand.The seed size of both cultivars is greater than that of all other cultivars.These large‐seeded cultivars will be preferred by farmers, traders, consumers, and processors. [ABSTRACT FROM AUTHOR]

Information to aid the selection of suitable cultivated areas remains meager for mung bean, despite it being a socio-economically important legume crop in Thailand. Hence, a user-friendly soil assessment tool is required to help properly choose planting areas. We aimed to provide a decision support system for mung bean cultivation in central Thailand. Soil suitability classes were performed using relevant factors and data essential for mung bean cultivation in 22 provinces in central Thailand. A decision support system was developed as soil map and mobile phone application using data based on soil suitability classes. Information of mung bean growth and yield grown in experimental fields with different soil suitability classes was used for preliminary validation. The main areas were very suitable (S1) and moderately suitable (S3) for mung bean plantation, accounting for 1,319,841 and 1,327,804 ha, respectively. The number of pods per plant and yield per plant of mung bean were higher in S1 areas (12.83–16.65 pods per plant and 8.35–12.43 g/plant, respectively) than in S3 areas. The mung bean yield was also greater in S1 areas (1613.8–2158.7 kg/ha) than in S3 areas (735.8–1138.6 kg/ha). The findings suggest the possibility of using developed decision support system. [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]

Mung bean is vulnerable to bruchids (Callosobruchus spp.), resulting in low quality and losses worldwide. Developing resistant cultivars is the most effective, economical, and eco-friendly way to protect mung bean seeds from the damage of bruchids. Previously, we identified two gene loci that are tightly linked with bruchid resistance, which makes new cultivar development possible using molecular assisted selection (MAS). In the present study, marker-assisted backcross (MABC) breeding was employed to introgress the bruchid resistance gene VrPGIP2 locus from the donor parent V2802 into a popular cultivar, Kamphaeng Saen 1. Markers VrBR-SSR013 and DMB-SSR158 were used for foreground selection, and phenotypic selection was used for background selection. Three advanced inbred lines (R67-11, R67-22, and R92-15) carrying the resistance gene VrPGIP2 were developed from the BC3F6 population. Further analysis showed that the line R67-22 performed best; it was highly resistant to bruchids and showed excellent agronomic traits in the field. Therefore, R67-22 could be further evaluated in large-scale trials for release as a variety. [ABSTRACT FROM AUTHOR]

Seed dormancy in wild mungbean (Vigna radiata var. sublobata) may be useful for the breeding of cultivated mungbean (var. radiata) with pre-harvest sprouting resistance. Previous studies have identified two major quantitative trait loci (QTLs) for seed dormancy, HsA and Sdwa5.1.1 +, in wild mungbean that are possibly having the same locus or linked. However, these QTLs have not been confirmed/verified and a molecular basis of seed dormancy in mungbean is not yet known. In this study, we aimed to finely map the Sdwa5.1.1 + and identify candidate gene(s) for this locus. Microscopic observations revealed that wild mungbean "ACC41" seeds had a palisade cuticle layer, while cultivated mungbean "Kamphaeng Saen 2" (KPS2) seeds lacked this layer. Fine mapping using an F2 population developed from a cross between ACC41 and KPS2 revealed two linked QTLs, Sdwa5.1.1 + and Sdwa5.1.2 +, controlling seed dormancy. The Sdwa5.1.1 + was confirmed in an F2:3 population derived from the same cross and mapped to a 3.298-Kb region containing only one gene LOC106767068 , designated as VrKNAT7-1 , which encodes the transcription factor KNOTTED ARABIDOPSIS THALIANA7 (KNAT7), a class II KNOTTED1-LIKE HOMEOBOX (KNOX II) protein. VrKNAX7 sequence alignment between ACC41 and KPS2 revealed several polymorphisms in the coding, untranslated, and promoter regions. Quantitative real-time PCR (qRT-PCR) analysis revealed that the expression of VrKNAT7-1 and VrCYP86A , a putative downstream regulation of VrKNAT7-1 , in the seed coat of ACC41 is statistically much higher than that of KPS2. Altogether, these results indicate that VrKNAT7-1 controls physical seed dormancy in the wild mungbean ACC41. [ABSTRACT FROM AUTHOR]

The necrotrophic fungus Macrophomina phaseolina is an important pathogen of many crops, such as strawberry, maize, sorghum, potato, soybean, chickpea, and pigeon pea, and causes multiple diseases throughout the world. The microsclerotia, which are the source of primary inoculum, play an important role in the survival and spread of M. phaseolina, as well as disease initiation and development. South Asia has unique characteristics relative to countries with temperate climates, that is, warm temperature, high humidity, and reduced rainfall that influence the interaction between M. phaseolina and its hosts. This review discusses the distribution pattern, pathogen background, pathogenic and genetic variability, and the mitigation strategies applied worldwide to reduce the impact of diseases caused by M. phaseolina with a focus on dry root rot of mungbean and urdbean in South Asia. Dry root rot, caused by M. phaseolina, is an emerging disease of mungbean and urdbean in South Asia. Dry root rot research in South Asia has focused mostly on adopting disease mitigation strategies evolved in tropical to temperate climates such as cultural practices, chemical control, genetic resistance, and biological control. Although the disease is prevalent in most of South Asia, there have been very few studies on M. phaseolina and its host–parasite interaction. Therefore, additional research is required in this domain, which could result in improved understanding and management of M. phaseolina in the face of present and future climate extremes. [ABSTRACT FROM AUTHOR]

Key message: This paper reports fine mapping of qCLS for resistance to Cercospora leaf spot disease in mungbean and identified LOC106765332encoding TATA-binding-protein-associated factor 5 (TAF5) as the candidate gene for the resistance Cercospora leaf spot (CLS) caused by the fungus Cercospora canescens is an important disease of mungbean. A QTL mapping using mungbean F2 and BC1F1 populations developed from the "V4718" (resistant) and "Kamphaeng Saen 1" (KPS1; susceptible) has identified a major QTL controlling CLS resistance (qCLS). In this study, we finely mapped the qCLS and identified candidate genes at this locus. A BC8F2 [KPS1 × (KPS1 × V4718)] population developed in this study and the F2 (KPS1 × V4718) population used in a previous study were genotyped with 16 newly developed SSR markers. QTL analysis in the BC8F2 and F2 populations consistently showed that the qCLS was mapped to a genomic region of ~ 13 Kb on chromosome 6, which contains only one annotated gene, LOC106765332 (designated "VrTAF5"), encoding TATA-binding-protein-associated factor 5 (TAF5), a subunit of transcription initiation factor IID and Spt-Ada-Gcn5 acetyltransferase complexes. Sequence comparison of VrTAF5 between KPS1 and V4718 revealed many single nucleotide polymorphisms (SNPs) and inserts/deletions (InDels) in which eight SNPs presented in eight different exons, and an SNP (G4,932C) residing in exon 8 causes amino acid change (S250T) in V4718. An InDel marker was developed to detect a 24-bp InDel polymorphism in VrTAF5 between KPS1 and V4718. Analysis by RT-qPCR showed that expression levels of VrTAF5 in KPS1 and V4718 were not statistically different. These results indicated that mutation in VrTAF5 causing an amino acid change in the VrTAF5 protein is responsible for CLS resistance in V4718. [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]

Flowers with exposed stigma increase the outcrossing rate and are useful in developing improved hybrid crop cultivars. This exposure results mainly from the cellular morphology of the petal and pistil, but what affects the formation of the petal and pistil in the late developmental stages is less understood. Here, we characterized a novel floral mutant in mungbean (Vigna radiata), stigma exposed 1 (se1), which displays irregular petals and pistils. Floral organ initiation in the se1 mutant was normal, but petal and pistil growth malfunctioned during late development. A histological analysis revealed that the se1 mutant had wrinkled petals with knotted structures and elongated styles. The cellular morphology of the epidermal layers of the se1 petals was deformed, while the cell lengths in the styles increased. A genetic analysis indicated that the se1 phenotype is controlled by a single recessive gene, and it was mapped to chromosome 11. A sequence analysis suggested that a DUF1005-encoding gene, LOC106777793 , is the gene controlling the se1 phenotype. The se1 mutant possessed a single-nucleotide polymorphism that resulted in an amino acid change in VrDUF1005. Overexpression of VrDUF1005 in Arabidopsis resulted in rolling leaves and reduced floral size. Consequently, we proposed that VrSE1 functions to modulate cell division in petals and cell expansion in styles during the late developmental stages in mungbean. The se1 mutant is a new genetic resource for mung bean hybrid breeding. [ABSTRACT FROM AUTHOR]

Organ size and architecture of plants are important traits affecting crop yield and agronomic practices. An induced mutant, multiple-organ gigantism (MOG), of black gram (Vigna mungo) has been obtained, which shows gigantic leaves, fruit, seed, and architecture (plant height) but lower number of pods per plant. These traits are a pleiotropic effect of a single recessive gene, mog. In this study, we investigated variation of 16 agronomic and adaptive traits in a recombinant inbred line (RIL) population derived from a cross between the MOG mutant (V. mungo var. mungo) and wild black gram (V. mungo var. silvestris) accession TC2210 and identified quantitative trait loci (QTLs) controlling those traits to gain a better understanding of the effect of the mog gene on breeding. The results showed that most of the traits (100-seed weight, leaf size, and plant height) showed moderate narrow-sense heritability (h 2) (45–65%), while pod size and seed length (SDL) showed high h 2 (>75%) and pod dehiscence (shattering), and seed width (SDW) and days to flowering showed low h 2 (<35%). The QTLs for the traits were mapped onto a high-density linkage map developed for the RIL population. Inclusive composite interval mapping identified 42 QTLs in total for the 16 traits with number of QTLs per trait ranging from one to six. Major QTLs for the MOG phenotypes were clustered on linkage group (LG) 6, confirming the pleiotropic effect of the mog gene. Effect of the mog gene/QTL for the MOG phenotypic variations was not high, ranging from about 15% in plant height to 40% in leaf size. For 100-seed weight, which is the most interesting trait, the mog gene/QTL contributed about 30% of the total trait variation and showed an additive effect of only 0.51 g, which is only about 1.5-fold higher than that of the other five QTLs detected for this trait. These results indicated that mog gene expression is highly affected by environment and the effect of the gene toward organ size and plant height is not extraordinarily high. Implications of the findings of this study and exploiting of the MOG mutant in breeding were also discussed. [ABSTRACT FROM AUTHOR]

Two bruchid species, azuki bean weevil (Callosobruchus chinensis L.) and cowpea weevil (Callosobruchus maculatus F.), are the most important insect pests of mungbean [Vigna radiata (L.) Wilczek] after harvest. Improving bruchid resistance is a major goal for mungbean breeders. Bruchid resistance in mungbean is controlled by a single major locus, Br. The tightly linked VrPGIP1 and VrPGIP2, which encode polygalacturonase-inhibiting proteins (PGIPs), are the candidate genes at the Br locus associated with bruchid resistance. One VrPGIP1 resistance allele and two VrPGIP2 resistance alleles have been identified. In this study, we fine-mapped the bruchid-resistance genes in wild mungbean (V. radiata var. sublobata) accession ACC41 using the F2 population (574 individuals) derived from the 'Kamphaeng Saen 2' (susceptible) × ACC41 (resistant) cross. A QTL analysis indicated that the resistance to the azuki bean weevil and cowpea weevil in ACC41 is controlled by a major QTL (qBr5.1) and a minor QTL (qBr5.2), which are only 0.3 cM apart. qBr5.1 and qBr5.2 accounted for about 82% and 2% of the resistance variation in the F2 population, respectively. qBr5.1 was mapped to a 237.35-kb region on mungbean chromosome 5 containing eight annotated genes, including VrPGIP1 and VrPGIP2. An examination of the ACC41 VrPGIP1 and VrPGIP2 sequences revealed a new allele for VrPGIP1 (i.e., VrPGIP1-2). Compared with the wild-type sequence, VrPGIP1-2 has five SNPs, of which four cause amino acid changes (residues 125, 129, 188, and 336). A protein sequence analysis indicated that residues 125 and 129 in VrPGIP1-2 are in a β-sheet B1 region, whereas residues 188 and 336 are in a C10-helix region and at the end of the C-terminal region, respectively. Because the β-sheet B1 region is important for interactions with polygalacturonase (PG), residues 125 and 129 in VrPGIP1-2 likely contribute to bruchid resistance by inhibiting PG. Our results imply that VrPGIP1-2 is associated with the bruchid resistance of wild mungbean accession ACC41. This new resistance allele may be useful for breeding mungbean varieties exhibiting durable bruchid resistance. [ABSTRACT FROM AUTHOR]

Zombi pea [Vigna vexillata (L.) A. Rich] is an underutilized legume crop, with highly diverse wild species that carry genes conferring resistance to several biotic and abiotic stresses. The objective of this study was to construct a zombi pea genetic linkage map and locate quantitative trait loci related to salt resistance. A zombi pea F2 population (159 individuals) developed from a cross between the salt-resistant wild zombi pea accession JP235908 (var. ovata; female parent) and the salt-susceptible cultivated zombi pea accession TVNu240 (var. macrosperma; male parent) was genotyped with simple sequence repeat (SSR) and restriction site-associated DNA sequencing (RAD-seq) markers. A genetic linkage map with 10 linkage groups (LGs) was constructed based on 379 markers (136 SSR and 243 RAD-seq markers). The map spanned 793.25 cM, with a mean distance between adjacent markers of 2.14 cM. A comparative genome analysis revealed high macro-synteny between zombi pea and mung bean/adzuki bean, although several chromosomal translocations likely occurred in zombi pea. The salt tolerance of the F2:3 population was evaluated at the seedling stage under hydroponic conditions. Inclusive composite interval mapping identified three quantitative trait loci (QTLs) (qSaltol1.1 on LG1, qSaltol2.1 on LG2, and qSaltol6.1 on LG6) related to the salt resistance of the F2 population. The qSaltol1.1, qSaltol2.1, and qSaltol6.1 QTLs explained 13.3%, 7.6%, and 8.1% of the salt-resistance phenotypic variance, respectively. A comparative genome analysis revealed that qSaltol1.1 may correspond to the Saltol1.1 QTL conferring salt tolerance in beach cowpea [Vigna marina (Burm.) Merr.], which is a halophytic species. Moreover, two genes encoding a plasma membrane H+-ATPase and a gene encoding a cation/proton exchanger may contribute to the salt resistance of zombi pea and beach cowpea. These findings may be relevant for the breeding of salt-resistant zombi pea plants. [ABSTRACT FROM AUTHOR]

Key message : The Br locus confers bruchid resistance in mungbean; VrPGIP2 (encoding a polygalacturonase inhibitor) is a strong candidate gene for this resistance. The VrPGIP2 sequence differs between resistant and susceptible lines. Abstract: Azuki bean weevil ( Callosobruchus chinensis) and cowpea weevil ( Callosobruchus maculatus) are serious insect pests of mungbean during storage. Bruchid resistance in mungbean is controlled by a single dominant locus, Br. Although the Br locus has been located on a genetic map, molecular basis and function of the gene remain unknown. In this study, high-resolution mapping using a BCF population of 418 plants derived from a cross between 'Kamphaeng Saen 1' (KPS1; susceptible) and 'V2802' (resistant) using simple sequence repeat (SSR) markers delimited the Br locus to a genomic region of 38 Kb of chromosome 5 containing two annotated genes. EST-SSR marker DMB-SSR158 co-segregated perfectly with the Br locus. Bioinformatics analyses revealed that DMB-SSR158 corresponds to a gene encoding a polygalacturonase inhibitor (polygalacturonase-inhibiting protein PGIP) and was designated as VrPGIP2. Comparison of VrPGIP2 coding sequences between four bruchid-resistant (V2802, V1128, V2817 and TC1966) and four bruchid-susceptible (KPS1, Sulu-1, CM and an unknown accession) mungbean lines revealed six single nucleotide polymorphisms (SNPs) between the resistant and susceptible groups. Three of the six SNPs resulted in amino acid changes; namely, alanine (A) to serine (S) at position 320, leucine (L) to proline (P) at position 332, and threonine (T) to P at position 335 of the VrPGIP2 sequence in resistant lines, compared with that in susceptible lines. The A to S change at position 320 may affect the interaction between PGIP and polygalacuronase. These results indicate that VrPGIP2 is very likely the gene at the Br locus responsible for bruchid resistance in mungbean. [ABSTRACT FROM AUTHOR]

Mungbean yellow mosaic India virus (MYMIV) is a major constraint on mungbean production in South and Southeast Asia. The virus belongs to the genus Begomovirus, causing yellow mosaic disease and subsequently yield loss up to 75-100 %. The present study employed F and BCF populations derived from a cross between susceptible (BARImung 1; BM1) and resistant (BARImung 6; BM6) mungbeans to identify quantitative trait loci (QTLs) associated with resistance to MYMIV. Resistance to the virus was evaluated using F and BCF populations under field conditions in two locations in Bangladesh in 2012. A total of 1,165 simple sequence repeat markers from different legumes were used to detect the polymorphism between BM1 and BM6. Sixty-one polymorphic markers were used to construct a linkage map comprising 11 linkage groups. Composite interval mapping consistently identified two major QTLs, qMYMIV2 on linkage group 2 and qMYMIV7 on linkage group 7, conferring the resistance in both F and BCF populations. qMYMIV2 and qMYMIV7 accounted for 31.42-37.60 and 29.07-47.36 %, respectively, of the disease score variation, depending on populations and locations. At both loci, the resistant alleles were contributed by the parent BM6. qMYMIV2 appeared to be common to a major QTL for MYMIV resistance in mungbean reported previously, while qMYMIV7 is a new QTL for the resistance. The markers linked to the QTLs in this study are useful in marker-assisted breeding for development of mungbean varieties resistant to MYMIV. [ABSTRACT FROM AUTHOR]

Yellow mosaic disease (YMD) is one of the major diseases affecting mungbean (Vigna radiata (L.) Wilczek). In this study, we report the mapping of the quantitative trait locus (QTL) for mungbean yellow mosaic India virus (MYMIV) resistance in mungbean. An F8 recombinant inbred line (RIL) mapping population was generated in Thailand from a cross between NM10-12-1 (MYMIV resistance) and KPS2 (MYMIV susceptible). One hundred and twenty-two RILs and their parents were evaluated for MYMIV resistance in infested fields in India and Pakistan. A genetic linkage map was developed for the RIL population using simple sequence repeat (SSR) markers. Composite interval mapping identified five QTLs for MYMIV resistance: three QTLs for India (qYMIV1, qYMIV2 and qYMIV3) and two QTLs for Pakistan (qYMIV4 and qYMIV5). qYMIV1, qYMIV2, qYMIV3, qYMIV4 and qYMIV5 explained 9.33%, 10.61%, 12.55%, 21.93% and 6.24% of variation in disease responses, respectively. qYMIV1 and qYMIV4 appeared to be the same locus and were common to a major QTL for MYMIV resistance in India identified previously using a different resistant mungbean. [ABSTRACT FROM AUTHOR]

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Powdery mildew (PM) is a common and serious disease of mungbean [ Vigna radiata (L.) Wilczek]. A few quantitative trait loci (QTL) for PM resistance in mungbean have been reported. The objective of this study was to locate QTL for PM resistance in two resistant accessions V4718 and RUM5. Simple sequence repeat markers were analyzed in an F population from a cross between Kamphaeng Saen 1 (KPS1; susceptible to PM) and V4718 (resistant to PM), and in F and BCF populations from a cross between Chai Nat 60 (CN60; susceptible to PM) and RUM5 (resistant to PM). Progenies of 134 F and F lines derived from KPS1 × V4718, and 190 F and 74 BCF lines derived from CN60 × RUM5 and CN60 × (CN60 × RUM5), respectively, were evaluated for response to PM under field conditions. Multiple interval mapping identified a major QTL on linkage group (LG) 9 and two minor QTL on LG4 for the resistance in V4718, and detected two major QTL on LG6 and LG9 and one minor QTL on LG4 for the resistance in RUM5. Comparative linkage analysis of the QTL for PM resistance in this study and in previous reports suggests that the resistance QTL on LG9 in V4718, RUM5, ATF3640 and VC6468-11-1A are the same locus or linked. One QTL on LG4 is the same in three sources (V4718, RUM5 and VC1210A). Another QTL on LG6 is the same in two sources (RUM5 and VC6468-11-1A). In addition, one QTL in V4718 on LG4 appears to be a new resistance locus. These different resistance loci will be useful for breeding durably PM-resistant mungbean cultivars. [ABSTRACT FROM AUTHOR]

Waterlogging is severe abiotic stress during mung bean (Vigna radiata (L.) R. Wilczek var. radiata) production. Waterlogging impacts yield loss for the legume crop by around 40%-70%, depending on the severity and duration of the waterlogging. In total, 107 collected mung bean varieties were evaluated under managed waterlogging. The F2 population from crossing between waterlogging-tolerant and -susceptible mung bean varieties were screened under waterlogging conditions. Morphological responses to the waterlogging were recorded. Correlation and path coefficient analyses were used to identify essential traits for waterlogging tolerance and seed yield potential under water stress. Mung bean varieties in clusters 5 and 6 were high waterlogging tolerance with survival rates of 66.66% and 61.11%, respectively. Of 199 F2 lines from crossings between the Kamphaeng Sean2 and W162, 20 lines presented high waterlogging tolerance. The injury score was negatively correlated with the number of leaves at the final date of waterlogging (-0.845) and 1 wk after terminating the waterlogging (-0.885). At the final date of waterlogging condition, the number of leaves and leaf greenness stability index directly affected leaf injury at -0.5928 and -0.4385. One week after waterlogging termination, only the number of leaves affected the leaf injury at -0.8599. The number of leaves directly affected seed yield components at 0.6534 and higher than the direct effect of the other traits. Thus, the number of leaves was a suitable morphological parameter along with the injury score for selecting waterlogging tolerance. The number of leaves was a suitable parameter for selecting high seed yield potential under waterlogging conditions. [ABSTRACT FROM AUTHOR]

Abstract: Foliar chlorosis caused by iron deficiency of plants grown on calcareous soil results in substantial crop yield loss and is an important in crop production problem. The objective of this study was to identify the quantitative trait locus (QTL) controlling resistance to iron deficiency chlorosis (IDC) in mungbean. An RIL population of 122 F8 lines developed from the cross between a susceptible cultivar, “Kamphaeng Saen 2” and a resistant line, “NM10-12” was genetically analyzed with simple sequence repeat (SSR) and amplified fragment length polymorphism (AFLP) markers. The population was evaluated for IDC resistance in an iron deficient field by visually scoring and SPAD measurements in 2010 and 2011. Segregation of the visual scores and SPAD values of the RILs in both years suggested quantitative inheritance of the resistance to IDC. Visual score and SPAD value from each year and combined data were used for QTL analysis. Single marker analysis revealed that 12 DNA markers from 3 linkage groups (LG) associated with the resistance. Four SSR and two AFLP markers on LG 3 associated with the resistance in all cases. Composite interval mapping identified two QTLs, qIDC3.1 and qIDC2.1, controlling the resistance. qIDC3.1 on LG 3 was identified from visual scores and SPAD values to account for 12.12% and 41.67% of the total variation depending on traits measured and years. qIDC2.1 on LG 2 was detected only from visual score data in 2010 and explained 45.66% of the total variation. The qIDC3.1 was the same as qIR which was the major QTL previously reported for IDC in mungbean grown in hydroponic conditions. The SSR markers CEDG084 and CEDC031 flanked and closely linked to the qIDC are useful for marker-assisted selection for mungbean resistance to IDC. [Copyright &y& Elsevier]

The genetic differences between mungbean and its presumed wild ancestor were analyzed for domestication related traits by QTL mapping. A genetic linkage map of mungbean was constructed using 430 SSR and EST-SSR markers from mungbean and its related species, and all these markers were mapped onto 11 linkage groups spanning a total of 727.6 cM. The present mungbean map is the first map where the number of linkage groups coincided with the haploid chromosome number of mungbean. In total 105 QTLs and genes for 38 domestication related traits were identified. Compared with the situation in other Vigna crops, many linkage groups have played an important role in the domestication of mungbean. In particular the QTLs with high contribution were distributed on seven out of 11 linkage groups. In addition, a large number of QTLs with small contribution were found. The accumulation of many mutations with large and/or small contribution has contributed to the differentiation between wild and cultivated mungbean. The useful QTLs for seed size, pod dehiscence and pod maturity that have not been found in other Asian Vigna species were identified in mungbean, and these QTLs may play the important role as new gene resources for other Asian Vigna species. The results provide the foundation that will be useful for improvement of mungbean and related legumes. [ABSTRACT FROM AUTHOR]

Phytic acid (PA) is the storage form of phosphorus (P) in seeds and plays an important role in the nutritional quality of food crops. There is little information on the genetics of seed and seedling PA in mungbean [Vigna radiata (L.) Wilczek]. Quantitative trait loci (QTL) were identified for phytic acid P (PAP), total P (TP), and inorganic P (IP) in mungbean seeds and seedlings, and for flowering, maturity and seed weight, in an F2 population developed from a cross between low PAP cultivated mungbean (V1725BG) and high PAP wild mungbean (AusTRCF321925). Seven QTLs were detected for P compounds in seed; two for PAP, four for IP and one for TP. Six QTLs were identified for P compounds in seedling; three for PAP, two for TP and one for IP. Only one QTL co-localized between P compounds in seed and seedling suggesting that low PAP seed and low PAP seedling must be selected for at different QTLs. Seed PAP and TP were positively correlated with days to flowering and maturity, indicating the importance of plant phenology to seed P content. [ABSTRACT FROM AUTHOR]

Cercospora leaf spot (CLS) caused by the fungus Cercospora canescens Illis & Martin is a serious disease in mungbean ( Vigna radiata (L.) Wilczek), and disease can reduce seed yield by up to 50%. We report here for the first time quantitative trait loci (QTL) mapping for CLS resistance in mungbean. The QTL analysis was conducted using F (KPS1 × V4718) and BCF [(KPS1 × V4718) × KPS1] populations developed from crosses between the CLS-resistant mungbean V4718 and CLS-susceptible cultivar Kamphaeng Saen 1 (KPS1). CLS resistance in F populations was evaluated under field conditions during the wet seasons of 2008 and 2009, and resistance in BCF was evaluated under field conditions during the wet season in 2008. Seven hundred and fifty-three simple sequence repeat (SSR) markers from various legumes were used to assess polymorphism between KPS1 and V4718. Subsequently, 69 polymorphic markers were analyzed in the F and BCF populations. The results of segregation analysis indicated that resistance to CLS is controlled by a single dominant gene, while composite interval mapping consistently identified one major QTL ( qCLS) for CLS resistance on linkage group 3 in both F and BCF populations. qCLS was located between markers CEDG117 and VR393, and accounted for 65.5-80.53% of the disease score variation depending on seasons and populations. An allele from V4718 increased the resistance. The SSR markers flanking qCLS will facilitate transferral of the CLS resistance allele from V4718 into elite mungbean cultivars. [ABSTRACT FROM AUTHOR]

In this paper, we report the development and characterization of genic microsatellite markers for mungbean by mining sequence database, and transferability of the markers to Asian Vigna species. A total of 157 markers were designed upon searching for SSR in 830 transcript sequences. Thirty-three loci revealed single copy polymorphism in a panel of 17 mungbean accessions with number of alleles ranging from 2 to 8, and observed heterozygosity from 0 to 0.3125. Seven loci deviated from Hardy-Weinberg Equilibrium. Two pairwise combinations of allele frequencies implied linkage disequilibrium. Cross-species amplification in 19 taxa of Asian Vigna using 85 primers showed that amplification rates varied between 80% (V. aconitifolia) to 95.3% (V. reflexo-pilosa). These mungbean genic microsatellite markers will be useful to study genetic resource and conservation of Asian Vigna species. [ABSTRACT FROM AUTHOR]

Abstract: We evaluated 9 qualitative and 21 quantitative traits in 340 diverse cultivated mungbean accessions collected at AVRDC-the World Vegetable Center, Taiwan to assess the extent and pattern of their diversity with respect to the traits measured. We also estimated broad-sense heritability (H) and expected genetic advance (GA) from selection of major quantitative traits. The germplasm displayed a wide range of diversity for most of the traits evaluated. High genetic variability, moderate to high H and GA were found in yield components, i.e. 100-seed weight, seed weight per plant, and number of pods per plant. Phenology traits such as plant height, days to flowering, and days to maturity also showed high genetic variability and H, while GA was high for plant height but relatively low for days to flowering and days to maturity. Cluster analysis grouped the germplasm into 5 major and 1 minor clusters. In general, germplasm from India and West Asia were present in all major clusters, while those from Southeast Asia and other origins were mainly grouped into one cluster. Principal component analysis revealed that the first three PCs explained 74.9% of the total variation. The variance explained by PC1 was due to the variation in almost all traits. PC2 originated principally from number of pods per plant, number of branches per plant, pod width and seed length. Two-dimensional plots of PCs revealed that mungbeans from India and West Asia were widely distributed with some overlapping, although they could be partially distinguished. Mungbeans from Southeast Asia were differentiated from those from India and West Asia. Since the mungbeans from India have been most frequently and widely employed in breeding programs, we recommend that the germplasm from West Asia be exploited more in cultivar development to enrich the breeding gene pool. The results from this experiment can help mungbean breeders choose the right combinations of parental genotypes carrying the desirable characters. [Copyright &y& Elsevier]

Bruchid beetles or seed weevils are the most devastating stored pests of grain legumes causing considerable loss to mungbean ( Vigna radiata (L.) Wilczek). Breeding for bruchid resistance is a major goal in mungbean improvement. Few sources of resistance in cultivated genepool were identified and characterized, however, there has been no study on the genetic control of the resistance. In this study, we investigated the inheritance of seed resistance to Callosobruchus chinensis (L.) and C. maculatus (F.) in two landrace mungbean accessions, V2709BG and V2802BG. The F1, F2 and BC generations were developed from crosses between the resistant and susceptible accessions and evaluated for resistance to the insects. It was found that resistance to bruchids in seeds is controlled by maternal plant genotype. All F1 plants derived from both direct and reciprocal crosses exhibited resistance to the bruchids. Segregation pattern of reaction to the beetles in the F2 and backcross populations showed that the resistance is controlled by a major gene, with resistance is dominant at varying degrees of expressivity. Although the presence of modifiers was also observed. The gene is likely the same locus in both V2709BG and V2802BG. The resistant gene is considered very useful in breeding for seed resistance to bruchids in mungbean. [ABSTRACT FROM AUTHOR]

A novel set of microsatellite markers for mungbean [ Vigna radiata (L.) Wilczek] was developed from the public sequence database. Seventy-eight primers were designed and evaluated for polymorphism among 22 cultivated accessions. Eight polymorphic loci detected two to three alleles per locus with an average of 2.25. The observed heterozygosity varied from 0.00 to 0.18, while the expected heterozygosity ranged from 0.09 to 0.46. Among them, all eight loci showed significant departuring from Hardy–Weinberg equilibrium, while four pairs of loci displayed significant pairwise linkage disequilibrium values. All eight loci except DMB-SSR1 showed heterozygote deficiency. [ABSTRACT FROM AUTHOR]

• Vigna radiata Mildew locus O 12 (VrMLO12) gene locates in the same region with QTL conferring powdery mildew (PM) resistance in mungbean RUM5. • VrMLO12 sequencing analysis revealed two SNPs causing amino acid changes in VrMLO12 protein, a MLO clade II protein, in RUM5. • Gene mapping revealed association between VrMLO12 and powdery mildew resistance in RUM5. • This is the first report showing association between MLO Clade II and powdery mildew resistance in plants. Loss/reduction of function of Mildew Locus O (MLO) genes clade V and MLO clade IV has been shown to be responsible for powdery mildew (PM) resistance in several plant species. Mungbean (Vigna radiata) genome possesses 18 MLO genes, VrMLO1 - VrMLO18. A previous study using mungbean F 2 and BC 1 F 1 populations derived from a cross between "CN60″ (susceptible) and "RUM5″ (resistance) demonstrated that QTL qPMRUM5−3 is a major QTL for PM resistance caused by Erysiphe polygoni and is the same with major QTL qPMV4718−3 that confers PM resistance in "V4718″ (resistance). In this study, bioinformatics analysis revealed VrMLO12 locates in the qPMRUM5−3 region. Fine mapping in the F 2 and BC 1 F 1 populations using newly developed DNA markers including gene-specific markers demonstrated association between VrMLO12 and the PM resistance. Sequence analyses of VrMLO12 revealed that compared to susceptible mungbeans, RUM5 and V4718 possess SNPs in exon 10 and exon 13. The SNPs caused amino acid changes of VrMLO12, A387S and A476 G, respectively. The change occurred in transmembrane 6 domain and calmodulin binding domain (CaMBD) of the VrMLO12 protein, respectively. qRT-PCR showed that transcript expression level of VrMLO12 in RUM5 challenged with and without by E. polygoni was significantly higher than that in CN60. Phylogenetic analysis revealed that in contrast to previous findings that MLO proteins associated with PM resistance belong to MLO clade V and MLO clade IV, VrMLO12 belongs to MLO clade II. The result suggested that VrMLO12 may function differently from the other MLOs that associated with PM susceptibility. Our findings provide insight into the PM resistance in mungbean and tools for mungbean breeding. [ABSTRACT FROM AUTHOR]

Vigna mungo is cultivated in approximately 5 million hectares worldwide. The chloroplast genome of this species has not been previously reported. In this study, we sequenced the genome and transcriptome of the V. mungo chloroplast. We identified many positively selected genes in the photosynthetic pathway (e.g., rbcL, ndhF, and atpF) and RNA polymerase genes (e.g., rpoC2) from the comparison of the chloroplast genome of V. mungo, temperate legume species, and tropical legume species. Our transcriptome data from PacBio isoform sequencing showed that the 51-kb DNA inversion could affect the transcriptional regulation of accD polycistronic. Using Illumina deep RNA sequencing, we found RNA editing of clpP in the leaf, shoot, flower, fruit, and root tissues of V. mungo. We also found three G-to-A RNA editing events that change guanine to adenine in the transcripts transcribed from the adenine-rich regions of the ycf4 gene. The edited guanine bases were found particularly in the chloroplast genome of the Vigna species. These G-to-A RNA editing events were likely to provide a mechanism for correcting DNA base mutations. The V. mungo chloroplast genome sequence and the analysis results obtained in this study can apply to phylogenetic studies and chloroplast genome engineering. [ABSTRACT FROM AUTHOR]

Zombi pea (Vigna vexillata) is a legume crop that is resistant to several biotic and abiotic stresses. Callosobruchus maculatus and Callosobruchus chinensis are serious stored-insect pests of legume crops. We constructed a high-density linkage map and performed quantitative trait loci (QTLs) mapping for resistance to these insect species in zombi pea. An F2 population of 198 individuals from a cross between 'TVNu 240' (resistant) and 'TVNu 1623' (susceptible) varieties was used to construct a linkage map of 6,529 single nucleotide polymorphism markers generated from sequencing amplified fragments of specific loci. The map comprised 11 linkage groups, spanning 1,740.9 cM, with an average of 593.5 markers per linkage group and an average distance of 0.27 cM between markers. High levels of micro-synteny between V. vexillata and cowpea (Vigna unguiculata), mungbean (Vigna radiata), azuki bean (Vigna angularis) and common bean (Phaseolus vulgaris) were found. One major and three minor QTLs for C. chinensis resistance and one major and one minor QTLs for C. maculatus resistance were identified. The major QTLs for resistance to C. chinensis and C. maculatus appeared to be the same locus. The linkage map developed in this study will facilitate the identification of useful genes/QTLs in zombi pea. [ABSTRACT FROM AUTHOR]

In this study, 520 cultivated and 14 wild accessions of black gram (Vigna mungo (L.) Hepper) were assessed for diversity using 22 SSR markers. Totally, 199 alleles were detected with a mean of 9.05 alleles per locus. Wild black gram showed higher gene diversity than cultivated black gram. Gene diversity of cultivated accessions among regions was comparable, while allelic richness of South Asia was higher than that of other regions. 78.67% of the wild gene diversity presented in cultivated accessions, indicating that the domestication bottleneck effect in black gram is relatively low. Genetic distance analysis revealed that cultivated black gram was more closely related to wild black gram from South Asia than that from Southeast Asia. STRUCTURE, principal coordinate and neighbor-joining analyses consistently revealed that 534 black gram accessions were grouped into three major subpopulations. The analyses also revealed that cultivated black gram from South Asia was genetically distinct from that from West Asia. Comparison by SSR analysis with other closely related Vigna species, including mungbean, azuki bean, and rice bean, revealed that level of gene diversity of black gram is comparable to that of mungbean and rice bean but lower than that of azuki bean. [ABSTRACT FROM AUTHOR]

Mungbean (Vigna radiata) (2n = 2x = 22) is an important annual legume in Asia. It is widely grown in South and Southeast Asia, as well as China. The aim of this research was to use SSR markers to construct a linkage map and identify chromosome regions controlling some agronomic traits in mungbean. The mapping population comprised 186 F2 plants derived from a cross between an annual cultivated mungbean line 'KUML29-1-3' (Vigna radiata var. radiata) and an Australian wild perennial mungbean accession 'W021' (Vigna radiata var. sublobata). A total of 150 SSR primers were composed into 11 linkage groups, each containing at least 5 markers. The map spans 1,174.2 cM with the average distance between the adjacent markers of 7.8 cM. Comparing the mungbean map with azuki bean (Vigna angularis) and blackgram (Vigna mungo) linkage maps revealed extensive genome conservation between the three species. Twenty QTLs controlling major agronomic characters includingdays to first flower (FLD), days to first pod maturity (PDDM), days to harvest (PDDH), 100 seed weight (SD100WT), number of seeds per pod (SDNPPD) and pod length (PDL) were located on to the linkage map. Most of the QTLs were located on linkage groups 7 and 5. [ABSTRACT FROM AUTHOR]

Iron is a crucial nutrient for biological functions in plants. High-pH and calcareous soil is a major stress causing iron deficiency chlorosis (IDC) symptoms and yield losses in crops. Use of calcareous soil-tolerance genetic resources is the most effective preventative method to combat the effects of high-pH and calcareous soils. A previous study using a mungbean recombinant inbred line (RIL) population of the cross Kamphaeg Saen 2 (KPS2; IDC susceptible) × NM-10–12 identified a major quantitative trait locus (QTL), qIDC3.1 , which controls resistance and explains more than 40% of IDC variation. In this study, we fine-mapped qIDC3.1 and identified an underlying candidate gene. A genome wide association analysis (GWAS) using 162 mungbean accessions identified single nucleotide polymorphisms (SNPs) on chromosome 6; several SNPs were associated with soil plant analysis development (SPAD) values and IDC visual scores of mungbeans planted on calcareous soil, respectively. These SNPs corresponded to qIDC3.1. Using the same RIL population as in the previous study and an advanced backcross population developed from KPS2 and IDC-resistant inbred line RIL82, qIDC3.1 was further confirmed and fine-mapped to an interval of 217 kilobases harboring five predicted genes, including LOC106764181 (VrYSL3), which encodes a yellow stripe1-like-3 (YSL3) protein, YSL3 is involved in iron deficiency resistance. Gene expression analysis revealed that VrYSL3 was highly expressed in mungbean roots. In calcareous soil, expression of VrYSL3 was significantly up-regulated, and it was more obviously upregulated in the roots of RIL82, than in those of KPS2. Sequence comparison of VrYSL3 between the RIL82 and KPS2 revealed four SNPs that result in amino acid changes in the VrYSL3 protein and a 20-bp insertion/deletion in the promoter where a cis-regulatory element resides. Transgenic Arabidopsis thaliana plants overexpressing VrYSL3 showed enhanced iron and zinc contents in the leaves. Taken together, these results indicate that VrYSL3 is a strong candidate gene responsible for calcareous soil resistance in mungbean. [Display omitted] • Fine mapping and GWAS suggested VrYSL3 controls resistance to iron-deficiency chlorosis in mungbean. • VrYSL3 sequence alignment revealed polymorphisms causing amino acid changes in VrYSL3 protein. • YSL3 is involved in iron acquisition by monocots. However, our finding suggests that YSL3 is also used by dicots. [ABSTRACT FROM AUTHOR]