Habibabadi Venus Nourbakhsh, Majidi Mohammad Mahdi, Maibody Sayed-Ali-Mohammad Mirmohammady, Abtahi Mozhgan
Department of Agronomy and Plant Breeding, College of Agriculture, Isfahan University of Technology, Isfahan, 84156-83111, Iran.
BMC Plant Biol. 2025 Aug 28;25(1):1149. doi: 10.1186/s12870-025-07261-8.
As climate change intensifies, perennial plants face more frequent drought periods throughout their lifespan. Drought stress memory in certain plants significantly enhances their adaptability to challenging environmental circumstances. However, in open-pollinated crops, this process is influenced by population plasticity due to the type and degree of genetic diversity, and inbreeding depression. To understand how pre-exposure to moderate drought enhances the plants' response to subsequent severe stresses, four synthetic poly-crossed populations were constructed using parents with contrasting molecular and morphological genetic variation (i.e. narrow and wide genetic distance). The first and second generations were subsequently assessed in an outdoor pot experiment at Isfahan University of Technology over two years, 2018 and 2019, under three different moisture conditions: Control with normal irrigation, DIDII underwent mild drought stress during the stem elongation phase followed, by severe drought stress during flowering, and DII subjected only to severe drought stress during flowering.
Genotypes pre-exposed to DIDII treatment exhibited enhanced tolerance to subsequent severe drought compared to those exposed to DII treatment, indicating the importance of drought stress memory. However, trait-specific response observed for stress memory. The DIDII treatment improves dry matter yield, root volume, and root weight at different soil depths. Populations derived from parents with higher molecular and phenotypic variation were better suited for accurately predicting the performance of their progenies in terms of drought tolerance while not necessarily for stress memory. Inbreeding depression for root volume, root area, and root dry weight was affected by moisture conditions and the diversity level among the parental genotypes.
Our research may pave the way for understanding the mechanisms behind drought stress memory in grasses, which can be exploited in future studies to develop synthetic varieties with improved drought tolerance through selective breeding using populations with diverse genetic backgrounds.
随着气候变化加剧，多年生植物在其整个生命周期中面临更频繁的干旱期。某些植物中的干旱胁迫记忆显著增强了它们对具有挑战性的环境条件的适应性。然而，在异花授粉作物中，由于遗传多样性的类型和程度以及近亲繁殖衰退，这个过程会受到群体可塑性的影响。为了了解预先暴露于中度干旱如何增强植物对随后严重胁迫的反应，使用具有对比性分子和形态遗传变异（即窄遗传距离和宽遗传距离）的亲本构建了四个合成多交群体。随后在2018年和2019年的两年时间里，于伊斯法罕理工大学进行了一项室外盆栽试验，对第一代和第二代在三种不同水分条件下进行评估：正常灌溉对照、DIDII在茎伸长阶段经历轻度干旱胁迫，随后在开花期经历严重干旱胁迫，以及DII仅在开花期遭受严重干旱胁迫。
与暴露于DII处理的基因型相比，预先暴露于DIDII处理的基因型对随后的严重干旱表现出更强的耐受性，这表明干旱胁迫记忆的重要性。然而，观察到了胁迫记忆的性状特异性反应。DIDII处理提高了不同土壤深度的干物质产量、根体积和根重量。来自具有较高分子和表型变异的亲本的群体在耐旱性方面更适合准确预测其后代的表现，但不一定适用于胁迫记忆。根体积、根面积和根干重的近亲繁殖衰退受水分条件和亲本基因型之间的多样性水平影响。
我们的研究可能为理解禾本科植物干旱胁迫记忆背后的机制铺平道路，这可以在未来的研究中加以利用，通过使用具有不同遗传背景的群体进行选择性育种来培育具有更高耐旱性的合成品种。
