Characterization of host response to bruchids (Callosobruchus chinensis and C. maculatus) in 39 genotypes belongs to 12 Cajanus spp. And assessment of molecular diversity inter se

• Published in: Journal of stored products research Vol. 81; pp. 76 - 90
• Main Authors: Mishra, Sujit K., Nag, Atul, Naik, Aparupa, Rath, Sobha C., Gupta, Kapil, Gupta, Aditya K., Panigrahi, Jogeswar
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-03-2019
• Subjects: AMOVA; Bruchid resistance; In vitro antibiosis assay; Molecular diversity; Outlier analysis; Bruchid resistance; Molecular diversity; In vitro antibiosis assay; AMOVA; Outlier analysis
• ISSN: 0022-474X; 1879-1212
• DOI: 10.1016/j.jspr.2019.02.001

Thirty nine genotypes belong to 12 Cajanus species were characterized for host response to bruchids (C. chinensis and C. maculatus) using no-choice based in vivo and in vitro antibiosis assay, and these assays revealed seven genotypes of primary gene pool (C. cajan) were more susceptible to bruchid infestation as compared to the genotypes of secondary and tertiary gene pools. Among all the genotypes, C. cajanifolius acc. ICPW-31 showed higher degree of resistance to both the bruchids. The molecular diversity using CDDP and SCoT markers showed wide range of genetic variations among the 12 species of Cajanus, and was supported by estimates of Nei's genetic distance and fixation index (FST) based haplotype matrix. The genetic structure showed clustering of 39 genotypes into eight distinct groups (K = 8) on the basis of their allelic composition, and among them C. cajanifolius acc. ICPW 31 and ICPW 30 showed close affinity with the cultivars of C. cajan by sharing several alleles. AMOVA analyses showed the existence of higher extent of genetic variation both at the genotype (37%) and species (63%) level in the genus Cajanus. The dendrogram and the principal coordinate analysis (PCoA) placed the 39 genotypes into six major clusters at par with their sectional classification. MCheza and ARLEQUIN based outlier analysis revealed 13 common loci under balancing selection, which are supposed to be involved in maintenance of genetic polymorphism either at species or genotype level, and are assigned to putative gene families such as KNOX, WRKY, ERF, MYB, ABP1 and MADS. The in vivo and in vitro bruchid assay vis-à-vis the DNA marker based molecular diversity analysis affirmed the possible use of C. cajanifolius acc. ICPW-31 as donor genotype for the introgression of bruchid resistance allele(s) into cultivated genetic background.
•The genotypes of Cajanus cajan revealed higher degree of susceptibility whereas genotypes of C. cajanifolius and C. platycarpus showed resistance to bruchids.•SCoT and CDDP based molecular diversity analyses revalidated the genetic closeness between the cultivars of pigeonpea and the genotypes of C. cajanifolius•AMOVA based on PhiPT values showed that 63% of genetic variation was inter-specific, whereas 37% of genetic variation was intra-specific.•The genetic differentiation coefficient (Gst) across 12 Cajanus species was 0.814 and fixation index (FST) was 0.703. The Gst based gene flow among these species was estimated to be 0.114.•MCheza and ARLEQUIN based outlier analysis identified several loci contributing either balancing selection or positive selection.•The outlier loci belong to KNOX, WRKY, ERF, MYB, ABP1 and MADS gene families, and were putatively played role in regulation of host resistance to pests and pathogens and morpho-physiological diversity in the genus Cajanus.