Genetic dissection of grain iron and zinc concentrations in lentil (Lens culinaris Medik.)

Iron (Fe) and zinc (Zn) deficiencies are wide spread in South Asia and Africa. Biofortification of food crops is a viable means of addressing micronutrient deficiencies. Lentil is an important pulse crop that provides affordable source of proteins, minerals, fibre and carbohydrates for micronutrient deficient countries. An association mapping (AM) panel of 96 diverse lentil genotypes fromIndia and Mediterranean region was evaluated for three seasons and genotyped using 80 polymorphic simple-sequence repeat (SSR) markers for identification of the markers associated with grain Fe and Zn concentrations. A Bayesian model based clustering identified five subpopulations, adequately explaining the genetic structure of the AM panel. The linkage disequilibrium (LD) analysis usingmixed linear model (MLM) identified two SSR markers, GLLC106 and GLLC108, associated with grain Fe concentration explaining 17% and 6% phenotypic variation, respectively and three SSR markers (PBALC 364, PBALC 92 and GLLC592) associated with grain Zn concentration, explaining 6%, 8% and 13% phenotypic variation, respectively. The identified SSRs exhibited consistentperformance across three seasons and have potential for utilization in lentil molecular breeding programme.

Molecular characterisation of Aspergillus flavus isolates from peanut fields in India using AFLP

Aflatoxin contamination of peanut, due to infection by Aspergillus flavus, is a major problem of rain-fed agriculture in India. In the present study, molecular characterisation of 187 Aspergillus flavus isolates, which were sampled from the peanut fields of Gujarat state in India, was performed using AFLP markers. On a pooled cluster analysis, the markers could successfully discriminate among the ‘A’, ‘B’ and ‘G’ group A. flavus isolates. PCoA analysis also showed equivalent results to the cluster analysis. Most of the isolates from one district could be clustered together, which indicated genetic similarity among the isolates. Further, a lot of genetic variability was observed within a district and within a group. The results of AMOVA test revealed that the variance within a population (84%) was more than that between two populations (16%). The isolates, when tested by indirect competitive ELISA, showed about 68.5% of them to be atoxigenic. Composite analysis between the aflatoxin production and AFLP data was found to be ineffective in separating the isolate types by aflatoxigenicity. Certain unique fragments, with respect to individual isolates, were also identified that may be used for development of SCAR marker to aid in rapid and precise identification of isolates.

Utilization of intron-flanking EST-specific markers in the genetic characterization of Artemisia annua genotypes from the trans-Himalayan region of Ladakh, India.

Genetic variation was assessed utilizing intron-flanking EST-specific markers among genotypes of Artemesia annua collected from two sampling sites viz. Nubra (9,600 ft) and Leh (11,500 ft) valleys of the trans-Himalayan region, Ladakh, India. The available ESTs (3,60,906) sequences of A. annua were aligned with the genomic sequences of Arabidopsis to developed ‘intron-flanking’ EST-PCR based primers. These primers anneal with the conserved region of exon (flanking to the intron) and amplified the introns. Out of the 39 primers selected and tested on 20 genotypes of A. annua, we successfully exploited 81 codominant intron length polymorphism (ILP) markers, with an average of 2.08 markers per primer and 92.04% polymorphism detection. Clustering of genotypes revealed distribution of genotypes into 2 distinct clusters with respect to their site of collection. Significantly, this study demonstrates that Arabidopsis genome sequence can be useful in developing gene-specific PCR-based markers for other non-model plant species like A. annua in the absence of genome sequences.