Krishna Kumar Rai

Response of Lablab purpureus L. to high temperature stress and role of exogenous protectants in mitigating high temperature induced oxidative damages

Present study was conducted to explore the role of exogenous salicylic acid (SA), sodium nitroprusside (SNP), abscisic acid (ABA) and proline (PRO) in mitigating high-temperature (HT) induced oxidative stress in different Lablab purpureus L. cultivars. The attempt was made to examine whether these phytohormones, when applied exogenously, were able to regulate plant morpho-physiological behavior by modulating genes and proteins involved in antioxidant defense system. The HT stress induced membrane damage, degraded chlorophyll, generated redox metabolites and significantly reduced growth and biomass in all the cultivars. Among all the four treatments, foliar application of SA and SNP were most effective in the regulation of growth and physiological processes of the cultivars compared to ABA and PRO applications. Thus, signifying the protective role of SA and SNP in mitigation of HT induced oxidative stress and conferring HT stress tolerance in the cultivars. Gene expression and leaf proteome analysis revealed that these phytohormones were also involved in regulation of defense related gene expression, stress inducible proteins and de novo synthesis of specific proteins under HT stress. The experimental findings depict that foliar applications of SA and SNP enhances HT stress tolerance in lablab cultivars by modulating antioxidant defense system and by regulating bio-physical growth more effectively as compared to ABA and PRO application.

Investigating the impact of high temperature on growth and yield of Lablab purpureus L. inbred lines using integrated phenotypical, physiological, biochemical and molecular approaches

A continuous increase in global mean temperature has become a major challenge for present and future agricultural productivity at worldwide. Therefore, present study was conducted to assess the impact of high temperature (HT) stress on seven Lablab purpureus L. inbred lines along with two parents viz, Arka Vijay and Kashi Khushal as check, to evaluate any genotypic variations exist among inbred lines for HT stress tolerance. The results show that HT induced higher levels of foliar injury in all inbred lines that significantly increased membrane damage, declined photosynthetic pigment contents and redox metabolites which ultimately led to the reduction in their growth and yield. However, among all the inbred lines used, three inbred lines viz, VRBSEM-1, VRBSEM-3 and VRBSEM-15 showed comparatively enhanced enzymatic and non-enzymatic antioxidants with increased secondary metabolites content as well as improved growth and yield related traits, thereby confirming that these inbred lines were efficiently utilizing reactive oxygen species as signalling molecule which regulated their growth and developmental process under HT stress. DNA fingerprinting analysis through ISSR and RAPD markers also established the genetic relationships among the inbred lines that coincides with above physiological and biochemical characterization, and grouped VRBSEM-1 & VRBSEM-3 and VRBSEM-9 & VRBSEM-15 inbred lines into one group and VRBSEM-8, VRBSEM-10, VRBSEM-14 into another group. The experimental findings clearly depict that all the cultivars of L. purpureus L. showed differential response to HT stress. Inbred lines with enhanced biochemical and physiological traits can be crossed to high yielding agronomical elite materials which can help plant breeders in selecting resistant cultivars for the area experiencing high temperature during the cropping season.

Recent advancement in modern genomic tools for adaptation of Lablab purpureus L to biotic and abiotic stresses: present mechanisms and future adaptations

Hyacinth bean is an important traditional plant with substantial medicinal value. Being imperative, it is still less explored crop on genomic and transcriptomic scale that has indexed it as an “orphan” crop for its genome revolution. Among different crop legumes such as pigeon pea, chickpea, cowpea, soybean and common bean, hyacinth bean also serves as a significant source of nutrition for both tropical and temperate regions and execute an imperative function in fixing biological nitrogen in agriculture. Nonetheless, the productivity of hyacinth bean is restrained due to environmental and biotic cues. Thus, understanding of the genomic functions and identification of probable genes/proteins for major agronomic traits through transcriptomic approaches has become imperative to improve stress tolerance in hyacinth bean. For understanding the plant stress tolerance mechanisms, the deployment of functional genomics approaches viz., proteomics and metabolomics have become imperious in breeding programs in developing countries. These approaches have been successfully used in other legume crops to create protein reference maps and their exploitation through comparative approaches can greatly enhance the research and understanding of hyacinth bean biological processes to changing environmental conditions. In this review, emerging epigenomics, proteomics, metabolomics and phenomics approaches and their achievements both in model/crop legumes are discussed. Additionally, the review also provides an overview of the applications of advanced proteomics, metabolomics and next-generation sequencing technologies in the discovery of candidate biomarkers for the development of agronomically refined hyacinth bean which may further ensure food and nutritional security under adverse climacteric conditions in developing countries.