Tapping the untapped genetic potential of moth bean (Vigna centifolia) – a high temperature stress tolerance legume.

Abstract

Abiotic stresses, such as drought and extreme temperatures, pose significant challenges to crop production. Understanding the impact of abiotic stress factors on crop plants is crucial for implementing effective strategies in unfavourable agricultural environments. Moth bean (Vigna aconitifolia), considered one of the earliest cultivated crops within the Vigna genus, stands out as a robust legume known for its exceptional resilience to drought and high-temperature conditions, making it a staple in arid regions. In this research, our focus revolves around unravelling the intricate dynamics of root and shoot growth, delving into the intricate root architecture system (RAS), all in pursuit of uncovering the mechanisms underpinning the plant's adaptability and the key traits associated with its remarkable abiotic stress tolerance in wild moth bean (TN67) and cultivated moth bean (ICPMO056). Methodology: Heat stress conditions were induced by subjecting seedlings to a 7-day exposure at 40°C prior to harvesting. Drought stress was simulated through limited irrigation, with both short-term (7 days) and long-term (27 days) durations. To comprehensively assess the combined impact of concurrent drought and heat stress, a 7-day experiment was conducted involving three distinct treatments: Optimal conditions, Heat, and a combination of Heat and Drought. Various parameters were measured, including primary root length (PRL), root and shoot mass, leaf number and size, and hypocotyl length. Results and Discussion: Based on our findings, TN67 (wild variety) demonstrates greater abiotic stress tolerance compared to ICPMO 56 (Commercial variety), as indicated by its less pronounced responses to the experimental conditions. Plant phytohormones, such as abscisic acid and auxin, are known to play a significant role in stress tolerance. To investigate their impact, hormone treatment experiments were conducted. The results revealed a consistent inhibition of primary root length but a concurrent promotion of lateral root growth, which is considered a stress tolerance mechanism. Conclusion: A deeper understanding of the underlying factors driving this inter-genotypic variation in stress sensitivity requires further investigation. Exploring the molecular basis of these differences presents an important direction for future research, which could lead to the development of more resilient crop varieties capable of withstanding the challenges posed by climate change-induced abiotic stresses.