胁迫记忆对吴堡桑响应土壤干旱的生理与蛋白组调控机制

Drought events will be more frequent and severe due to global climate change, posing greater threaten on the development and productivity of woody trees. Stress memory is an important strategy for acclimation to complex climatic variations in plants, but its physiological and proteomic mechanisms in response to reiterated drought are largely unclear. Our previous studies indicate that the mulberry cultivar Wupu has stronger drought tolerance compared with other mulberry species under short-term drought. In this study, saplings of the mulberry cultivar Wupu are exposed to single drought and reiterated drought events, respectively. Water use efficiency, phytohormones, osmotic substances, ROS and antioxidant enzymes are analyzed to elucidate the physiological mechanism of drought stress memory in mulberry. Furthermore, by using iTRAQ technology, we intend to identify the differentially expressed proteins in response to drought, and reveal the proteomic regulations underlying drought stress memory of mulberry. Combining the results mentioned above, we aim to uncover the physiological and proteomic mechanisms of stress memory in response to reiterated drought in mulberry species. This study will not only enrich and develop our understandings to the molecular physiology of drought stress memory in mulberry, but also have practical implication on selective breeding of drought tolerant cultivars in other woody trees.

全球气候变化将导致干旱事件的发生更为频繁和严重，对木本植物的生长发育和生产力带来更大威胁。胁迫记忆是植物适应复杂气候环境的重要生存策略，但其在桑树应答干旱胁迫中的生理和蛋白调控机理还很不清楚。我们的前期研究发现，与其他品种的桑树相比，吴堡桑在短期干旱胁迫下的抗旱性较强。本项目拟以吴堡桑扦插苗为研究对象，对其分别进行单次干旱和周期性干旱处理，应用生理生化技术分析水分利用效率、植物激素、渗透调节物质、活性氧和抗氧化保护酶等抗旱相关指标的响应差异，揭示胁迫记忆对桑树干旱胁迫响应的生理调控机制；再通过iTRAQ技术进行蛋白组学分析，阐明差异表达蛋白在桑树干旱胁迫记忆中的分子调控机理。综合以上研究，明确胁迫记忆对桑树应答干旱胁迫的生理和蛋白调控机理。本项目的开展对于阐明胁迫记忆在桑树抗旱性的分子生理调控机制具有重要指导意义，也对桑树乃至其它林木资源评价和选育抗旱性较强的新品种具有重要实践意义。

随着全球气候变暖，干旱事件的发生将更为频繁和严重。多年生高大林木生命周期长，与一年生植物相比，其生长发育更易受到往复性干旱胁迫的威胁。胁迫记忆是植物在群落水平上适应复杂多变气候环境的生存策略，解析该能力如何在耐旱中发挥作用是阐释植物耐旱机制的重要层面。本项目以湖桑32号和7307两个耐旱性有一定差异的桑品种盆栽苗为研究对象，首先明确了单次干旱胁迫和周期干旱胁迫对桑苗生长速率和生物量的影响；再利用生理生化技术分析δ13C、植物激素、渗透调节物质、活性氧和抗氧化保护酶等抗旱相关指标，揭示胁迫记忆对桑树干旱胁迫响应的生理调控机制。在此研究基础上，利用RNA-seq和iTRAQ联合分析技术，阐释了参与调控胁迫记忆的一系列基因和蛋白及其作用机制。研究结果对于阐明胁迫记忆在桑树抗旱性的分子生理调控机制具有重要指导意义，也对桑树乃至其它林木资源评价和选育抗旱性较强的新品种具有重要实践意义。