Role of ethylene in acclimations to promote oxygen transport in roots of plants in waterlogged soils
Role of ethylene in acclimations to promote oxygen transport in roots of plants in waterlogged soils
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DOI：
10.1016/j.plantsci.2008.03.002
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发表时间：
2008-07
期刊：
影响因子：
5.2
通讯作者：
K. Shiono;H. Takahashi;T. Colmer;M. Nakazono
中科院分区：
文献类型：
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作者：
K. Shiono;H. Takahashi;T. Colmer;M. Nakazono
乙烯在植物适应土壤浸水的形态和解剖学方面发挥着核心作用。为了适应水涝，湿地物种甚至某些作物的根部会形成通气组织。通气组织是大的相互连接的气体空间，从芽连接到根尖附近。氧气通过根部通气组织中的扩散移动。在许多湿地物种中，径向氧损失（ROL）屏障大大减少了基部的氧气泄漏，进一步增强了氧气向顶端的扩散。通气组织有两种主要类型：分裂性通气组织和溶源性通气组织。裂殖性通气组织是通过细胞分离而形成的，没有细胞死亡。溶源性通气组织是由程序性细胞死亡（PCD）引起的。尽管许多湿地物种即使在排水条件下也会形成一些通气组织，但浸水期间植物中乙烯的积累会引起溶源性通气组织。乙烯积累可能导致 G 蛋白和其他信号转导级联的激活，其中增加的胞质 Ca2+ 是其中的一个组成部分。最后，PCD导致根皮层发生选择性细胞降解，细胞壁降解酶，如纤维素酶和果胶酶也被激活。另一方面，乙烯似乎不会诱导 ROL 屏障，至少在水稻根部是如此。因此，ROL 屏障的诱导和通气组织的形成似乎受到不同信号的调节。进一步阐明由乙烯感应启动的信号转导途径，以及非乙烯依赖性反应，以及控制ROL和通气组织屏障形成的基因，应该是未来植物耐涝研究的优先领域。
Ethylene plays a central role in morphological and anatomical acclimations of plants to soil waterlogging. To acclimate to waterlogging, roots of wetland species, and even some crops, form aerenchyma. Aerenchyma is large interconnected gas spaces that connect from shoot to near the tips of roots. Oxygen moves via diffusion in the root aerenchyma. In many wetland species, a barrier to radial oxygen loss (ROL) that greatly reduces oxygen leakage from basal parts, further enhances oxygen diffusion to the apex. Two main types of aerenchyma are recognized: schizogenous and lysigenous aerenchymas. Schizogenous aerenchyma is formed by cell separation without cell death. Lysigenous aerenchyma results from programmed cell death (PCD). Ethylene accumulation in plants during waterlogging induces lysigenous aerenchyma, although many wetland species form some aerenchyma even in drained conditions. The ethylene accumulation may result in the activation of G-proteins and other signal transduction cascades, of which increased cytosolic Ca2+is a component. Finally, PCD leading to selective cell degradation occurs in the root cortex, with cell wall degrading enzymes, such as cellulase and pectinase, also being activated. On the other hand, ethylene does not appear to induce the barrier to ROL, at least in roots of rice. Thus, induction of the barrier to ROL and formation of aerenchyma appear to be regulated by different signals. Further elucidation of signal transduction pathways initiated by ethylene sensing, as well as non-ethylene dependant responses, and of the genes regulated to control formation of the barrier to ROL and aerenchyma, should be priority areas for future research on plant tolerance of waterlogging.