Resilience in Hyacinth bean (Lablab purpureus (L.) Sweet): A combined approach of relative water content and gene expression analysis for drought tolerance

Abstract

To cope with water deficit, plants have evolved diverse drought tolerance mechanisms that involves physiological, biochemical and gene regulatory networks for their effective survival. This research investigated the relative water contents (RWC) and semi-reverse quantitative expression of plasma membrane intrinsic proteins (PIPs) drought-tolerance genes in Hyacinth bean (HB). Five accessions were randomly selected based on their seed morphology and were grown in planting buckets filled with topsoil in a randomized complete block design. After two weeks of seedling growth under normal conditions, drought stress was induced without water for 21 days in a greenhouse. In the same experiment, well-watered potted HB seedlings served as controls. Determination of the RWC followed an established protocol. RNA was isolated from leaf sample of the accessions and mRNA expression levels of the PIP gene was determined using real-time quantitative PCR (RT-qPCR) with GAPDH (glyceraldehyde – 3- phosphate dehydrogenase) gene as control. The results showed that the RWC of drought-treated accessions ranged from 26.17% (TLn-6) to 48.78% (TLn-2), while that of control varied from 49.61% (TLn-2) to 79.07% (TLn-70). The mean cycle quantification for the PIP amplification in the drought-treated samples ranged from 31.33 ± 0.079 (TLn-2) to 32.02 ± 0.364 (TLn-7) which were found to be higher than the control (28.63 ± 0.00).The expression level of drought-treated accessions was higher than that of the control accessions. The expression of PIP in both drought-induced and well hydrated accessions suggest the presence of drought regulatory genes in HB, thus making the crop a suitable candidate for climate-smart agriculture in the tropics.