Journal of Underutilized Legumes

Resilience in Hyacinth Bean (Lablab purpureus (L.) Sweet): A Combined Approach of Relative Water Content and Gene Expression Analysis for Drought Tolerance

J.O Popoola — 2024-03-12

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 picked 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.

Expression of abscisic acid using the candidate Gene NCED1 on drought stress bambara groundnut (Vigna subterranea (L.) Verdc) accessions

K.A. Odesola — 2024-03-31

Abscisic acid (ABA) functions as one of the numerous plant hormones governing a range of physiological processes in plants, including responses to water stress. In most plants, abscisic acid levels are supposedly increased under conditions of water deficit, leading to stomatal closure and reduced transpiration and ultimately a decrease in relative water content. There is little to no information related to the expressions of abscisic acid linkage to the drought tolerance usually attributed to Bambara groundnut. The study investigated the expression of Abscisic Acid using the candidate gene 9-cis-epoxycarotenoid dioxygenase (NCED1) in seven (7) Vigna subterranea [L.] Verdc accessions under both well-watered and water stress conditions. Three healthy seeds were planted per bag, with 500 mL water administered to the plant once a day on both treatments until two weeks after flowering when the water-stressed pots received no further watering. The leaf samples were collected for RNA extraction and then differing bands intensity from amplified cDNA bands were captured for densitometric analysis using the Image J imaging software. On the other hand, data was collected on relative water content (RWC) on the individual samples. The RWC values among the accessions ranged from 82.12% to 89.24% under the well-watered condition and 62.00% to 79.43% under the water-stressed condition. The observed ABA hormone gene expression profile suggests that all the seven Bambara groundnut accessions express ABA adequately under the two water conditions identified. This indicates tolerance to water stress and the effectiveness of identifying NCED1 as a marker in drought tolerance expression studies.

Phenotypic diversity within winged bean (Psophocarpus tetragonolobus L.) accessions

M.A. Adebayo — 2024-04-20

Exploring the potentials of winged bean for supply of plant protein, edible oil, minerals and anti-oxidants will make significant impacts in achieving a food and nutritionally secure world. Nineteen winged bean accessions assembled from diverse origins were assessed in an experiment in which entries were arranged in a randomized complete block design and replicated thrice. Twenty-five physiological, chronological, and morphometric traits assessed in the 19 accessions were subjected to principal component and cluster analyses based on Ward’s method. Genetic correlation coefficients were calculated among the recorded traits. The first seven principal component axes whose eigenvalues or latent roots exceeded 1.0 explained 82.8% of total variance. The 16 genetically correlated traits were delineated into four groups as revealed on Ward’s dendrogram. The biplot of the first two principal axes separated the 19 accessions into three groups while the cluster analysis based on minimum variance coefficients produced a dendrogram which, when truncated arbitrarily at 0.60 similarity level, resulted in four distinct clusters. The genetically correlated traits within each cluster will elicit correlated response where collection for one implies indirection choice for others in a winged bean improvement program. The accessions from each country were mostly grouped together implying that crosses among accessions between different countries rather than within a country may yield better results in winged been hybridization programs.