The role of chloroplasts in responding to drought stress in plants

粮食安全是世界面临的一个主要问题，由于人口增长和气候变化带来的新挑战，这个问题在未来几十年将变得更加紧迫(1)。由于灌溉受到限制，到2030年所需的大约50%的生产力增长将需要来自雨养农业，因此干旱是限制全球作物产量的主要非生物胁迫。由于光合作用对环境非常敏感，叶绿体在植物对包括干旱在内的环境胁迫的反应中起着核心作用。对于干旱胁迫，越来越多的证据表明，通过四吡咯前体处理增强叶绿体定位的四吡咯途径可以保护植物(2)。虽然机制尚不清楚，但血红素合成被认为是关键因素。血红素也是叶绿体和细胞核之间沟通的关键角色(3)，我们自己的转录组学结果显示逆行和干旱响应基因之间存在一些重叠。在这个项目中，我们将测试叶绿体到细胞核逆行信号的激活可以防止干旱以及干旱修饰叶绿体蛋白质组导致逆行信号变化的假设。

Food security is a major problem facing the World and one that is going to become more pressing in coming decades due to increased population and new challenges imposed by climate change (1). With a limit on irrigation, much of the estimated 50% increase in productivity required by 2030 will need to come from rain-fed agriculture and thus drought is the major abiotic stress limiting crop yields worldwide. Since photosynthesis is so sensitive to the environment, the chloroplast plays a central role in the response of plants to environmental stresses including drought. For drought stress, there is an increasing body of evidence that enhancement of the chloroplast-localised tetrapyrrole pathway through treatment with tetrapyrrole precursors can protect plants (2). Although the mechanism is not well understood, heme synthesis is suggested to be the critical factor. Heme is also a key player in communication between the chloroplast and nucleus (3) and our own transcriptomic results show some overlap between retrograde- and drought-responsive genes. In this project we will test the hypotheses that activation of chloroplast-to-nucleus retrograde signalling protects against drought and that drought modifies the chloroplast proteome to bring about these changes in retrograde signalling.