ABSTRACT
The aim of this study was to identify candidate resistance genes for late leaf spot (LLS) and rust diseases in peanut (Arachis hypogaea L.). We used a double-digest restriction-site associated DNA sequencing (ddRAD-Seq) technique based on next-generation sequencing (NGS) for genotyping analysis across the recombinant inbred lines (RILs) derived from a cross between a susceptible line, TAG 24, and a resistant line, GPBD 4. A total of 171 SNPs from the ddRAD-Seq together with 282 markers published in the previous studies were mapped on a genetic map covering 1510.1 cM. Subsequent quantitative trait locus (QTL) analysis revealed major genetic loci for LLS and rust resistance on chromosomes A02 and A03, respectively. Heterogeneous inbred family-derived near isogenic lines and the pedigree of the resistant gene donor, A. cardenasii Krapov. & W.C. Greg., including the resistant derivatives of ICGV 86855 and VG 9514 as well as GPBD 4, were employed for whole-genome resequencing analysis. The results indicated the QTL candidates for LLS and rust resistance were located in 1.4- and 2.7-Mb genome regions on A02 and A03, respectively. In these regions, four and six resistance-related genes with deleterious mutations were selected as candidates for LLS and rust resistance, respectively. These delimited genomic regions may be beneficial in breeding programs aimed at improving disease resistance and enhancing peanut productivity.
ABSTRACT
A high performance anion exchange chromatography (HPAEC) coupled with pulsed amperometric detection (PAD) was optimised to separate with precision, accuracy and high reproducibility soluble sugars including oligosaccharides present in pulse meal samples. The optimised method within 20min separated myo-inositol, galactinol, glucose, fructose, sucrose, raffinose, stachyose and verbascose in chickpea seed meal extracts. Gradient method of eluting solvent (sodium hydroxide) resulted in higher sensitivity and rapid detection compared to similar analytical methods. Peaks asymmetry equivalent to one and resolution value ⩾1.5 support column's precision and accuracy for quantitative determinations of soluble sugars in complex mixtures. Intermediate precision determined as relative standard deviation (1.8-3.5%) for different soluble sugars confirms reproducibility of the optimised method. The developed method has superior sensitivity to detect even scarcely present verbascose in chickpea. It also quantifies myo-inositol and galactinol making it suitable both for RFO related genotype screening and biosynthetic studies.
Subject(s)
Carbohydrates/analysis , Chromatography, High Pressure Liquid/methods , Chromatography, Ion Exchange/methods , Cicer/chemistry , Plant Extracts/analysis , Raffinose/analysis , Seeds/chemistry , Chromatography, High Pressure Liquid/instrumentation , Chromatography, Ion Exchange/instrumentationABSTRACT
To develop genetic improvement strategies to modulate raffinose family oligosaccharides (RFO) concentration in chickpea ( Cicer arietinum L.) seeds, RFO and their precursor concentrations were analyzed in 171 chickpea genotypes from diverse geographical origins. The genotypes were grown in replicated trials over two years in the field (Patancheru, India) and in the greenhouse (Saskatoon, Canada). Analysis of variance revealed a significant impact of genotype, environment, and their interaction on RFO concentration in chickpea seeds. Total RFO concentration ranged from 1.58 to 5.31 mmol/100 g and from 2.11 to 5.83 mmol/100 g in desi and kabuli genotypes, respectively. Sucrose (0.60-3.59 g/100 g) and stachyose (0.18-2.38 g/100 g) were distinguished as the major soluble sugar and RFO, respectively. Correlation analysis revealed a significant positive correlation between substrate and product concentration in RFO biosynthesis. In chickpea seeds, raffinose, stachyose, and verbascose showed a moderate broad sense heritability (0.25-0.56), suggesting the use of a multilocation trials based approach in chickpea seed quality improvement programs.
