Heat shock proteins (HSPs) have a significant role in protein folding and are considered as prominent candidates for development of heat-tolerant crops. Understanding of wheat HSPs has great importance since wheat is severely affected by heat stress, particularly during the grain filling stage. In the present study, efforts were made to identify HSPs in wheat and to understand their role during plant development and under different stress conditions. HSPs in wheat genome were first identified by using Position-Specific Scoring Matrix (PSSMs) of known HSP domains and then also confirmed by sequence homology with already known HSPs. Collectively, 753 TaHSPs including 169 TaSHSP, 273 TaHSP40, 95 TaHSP60, 114 TaHSP70, 18 TaHSP90 and 84 TaHSP100 were identified in the wheat genome. Compared with other grass species, number of HSPs in wheat was relatively high probably due to the higher ploidy level. Large number of tandem duplication was identified in TaHSPs, especially TaSHSPs. The TaHSP genes showed random distribution on chromosomes, however, there were more TaHSPs in B and D sub-genomes as compared to the A sub-genome. Extensive computational analysis was performed using the available genomic resources to understand gene structure, gene expression and phylogentic relationship of TaHSPs. Interestingly, apart from high expression under heat stress, high expression of TaSHSP was also observed during seed development. The study provided a list of candidate HSP genes for improving thermo tolerance during developmental stages and also for understanding the seed development process in bread wheat.
22 June 2020 in Genetic Resources and Crop Evolution
Domesticated lentil has a relatively narrow genetic base globally and most released varieties are susceptible to severe biotic and abiotic stresses. The crop wild relatives could provide new traits of interest for tailoring novel germplasm and cultivated lentil improvement. The primary objective of this study was to evaluate wild lentil accessions for identification of economically viable agro-morphological traits and resistance against major biotic stresses. The study has revealed substantial variations in seed yield and its important component characters. Further, the diversity analysis of wild accessions showed two major clusters which were bifurcated into sub-clusters, thereby suggesting their wider genetic divergence. However, principal component analysis exhibited that seed yield plant-1, number of seeds plant-1, number of pods plant-1, harvest index and biological yield plant-1 contributed significantly to the total genetic variation assessed in wild lentil taxa. Moreover, some of the wild accessions collected from Syria and Turkey regions showed resistance against more than one disease indicating rich diversity of lentil genetic resources. The identification of most promising genotypes carrying resistance against major biotic stresses could be utilized in the cultivated or susceptible varieties of lentil for enhancing genetic gains. The study has also identified some trait specific accessions, which could also be taken into the consideration while planning distant hybridization in lentil.
The wild species of chickpea have tremendous potential for enhancing genetic gains of cultigen and have resistant accessions against major biotic and abiotic stresses. In the present study, two wild annual accessions, one each of C. reticulatum Ladiz. (ILWC 229) and C. echinospermum Davis (ILWC 246) were assessed for their agro-morphological features and hybridized with different cultivated varieties (BGD 72, PBG 5, ICKG 96029, Pusa 372 and JG 11) of chickpea. Fertile F1 plants were developed as revealed by their normal meiotic chromosomal configuration including high pollen stainability percentage and seed set. The effect of genetic and non-genetic factors on crossability performance with respect to pod and seed set was also evident under two growing conditions of North-Western Indian Himalayas. The segregation analysis using F2 phenotypic ratio of some distinct morphological (plant growth habit, stem pigmentation at seedling stage and testa texture) characters indicated their monogenic inheritance pattern. The study would also be useful to chickpea breeders to identify true to type interspecific plants. Further, the F1, F2 and F3 generations of all seven crosses along with parents were evaluated under natural field condition to determine the extent of variability created into the cultivated background of chickpea. There was a wide range of variation in F3 population against cold stress, suggesting selection of tolerant recombinant lines at an early stage. We also studied fruitful heterosis (%) as a useful approach, instead of residual heterosis to identify better performing transgressive segregants. The values of most of the interspecific crosses for important traits assessed in F2 and F3 generations were higher than that of better parent, suggesting isolation of inbred vigour for pod numbers and earliness. The results indicated that wild Cicer annual accessions of C. reticulatum and C. echinospermum species can be exploited after proper screening for traits of interest for diversification of cultivated gene pool and subsequent use in chickpea improvement.