Screening Tunisian natural population of Brachypodium hybridum for drought stress at germination and vegetative stages: insight into potential sources of variability for drought adaptation in Brachypodium hybridum

• Published in: Cereal research communications 2024-09, Vol.52 (3), p.1001-1013
• Main Authors: Ibrahim, Yosra, Ellouzi, Hasna, Abdelly, Chedly, Taamalli, Wael, Gandour, Mhemmed
• Format: Article
• Language: English
• Subjects: Agriculture; Biomedical and Life Sciences; Life Sciences; Original Paper; Plant Breeding/Biotechnology; Plant Genetics and Genomics; Plant Physiology
• ISSN: 0133-3720; 1788-9170
• DOI: 10.1007/s42976-023-00447-6

Water deficiency has become a serious ecological problem facing all mankind, and drought has become a key factor constraining the development of agricultural production. Gaining insights into drought response mechanisms is vital for crop adaptation. We present, here, a multifactorial study from germination to vegetative drought stages in the model plant Brachypodium hybridum . A total of 200 genotypes representing 10 natural populations (Fayedh, Enfidha, Jbel Zaghouan, Haouaria, Raouad, Sejnen, Ain Drahem, El Kef, Daouar El Hej Wniss and Djerba) which represent almost all the bioclimatic regions in Tunisia were used. High variation in germination capacity under drought stress was found between studied populations. It reaches 100% at 250 mV for Djerba population and decrease up to 40% at 100 mV. Drought caused significant increase in oxidative stress. Interestingly, genotype 8/14 originated from El Kef exhibited the highest leaf H 2 O 2 content, resulting in higher leaf MDA accumulation. Consistently, no significant changes were observed in-SOD, CAT and GPX activities in both leaves and roots, relatively to unstressed state. Different profile was recorded in 6/9 originated from Raoued in which the most pronounced levels of H 2 O 2 and MDA were observed in drought stressed roots. Concurrently, root CAT activity increased by 22-fold relatively to unstressed plants. Drought stress resulted in a decrease in H 2 O 2 content, mitigation of lipid peroxidation in both leaves and roots of 6/5 genotype originated from Raoued, with a simultaneous increase in leaf and root SOD activity. This was associated with enhanced GPX activity where 75 and 40% of increase were recorded in genotype 6/5 in leaves and roots.