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，而且由于人口增加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。在灌溉受到限制的情况下，到2030年，估计需要提高50%的生产力，其中很大一部分将需要来自雨水灌溉的农业，因此干旱是限制全球作物产量的主要非生物压力。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，有越来越多的证据表明，通过四吡咯前体处理来增强叶绿体定位的四吡咯途径可以保护植物(2)。尽管其机制尚不清楚，但血红素的合成被认为是关键因素。血红素也是叶绿体和细胞核之间通讯的关键角色(3)，我们自己的转录结果表明逆行和干旱反应基因之间有一些重叠。在这个项目中，我们将测试以下假设：激活叶绿体到细胞核的逆行信号对干旱具有保护作用，以及干旱修改叶绿体蛋白质组以实现这些逆行信号的变化。

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.