Plant Physiol:南京农业大学沈文飚教授课题组发表植物干旱应答信
2015年12月，国际植物学权威杂志《Plant Physiology》在线发表南京农业大学沈文飚教授课题组关于植物干旱应答信号研究进展，论文题为“Arabidopsis HY1-modulated Stomatal Movement: An Integrative Hub that its functionally Associated with ABI4 for the Dehydration-induced ABA Responsiveness”。谢彦杰研究员为论文第一作者，沈文飚教授为通讯作者。
血红素加氧酶(HO)/一氧化碳(CO)是植物中新发现的信号系统。该课题组先前的研究已经发现，上调拟南芥HO1(HY1)表达能提高其耐盐性(Xie et al., plant J, 2011)。在此工作的基础上，该研究解析了拟南芥血红素加氧酶HY1调控耐旱的分子机制 。研究发现，HY1突变导致拟南芥更耐旱，而HY1过表达导致拟南芥更易脱水，上述现象与ABA信号有关。进一步通过转录组测序筛选并验证干旱下受HY1调控的ABA信号转导差异表达基因，发现ABI4转录因子受HY1调控;HY1突变导致的拟南芥对ABA超敏感和耐旱表型能被ABI4突变所逆转，HY1突变体气孔关闭对ABA超敏感的表型也能被ABI4突变所回补。后续实验发现HY1-ABI4信号通过调控RbohD产生的ROS来控制气孔关闭。上述结果阐明了ABA信号途径中ABI4信号介导HY1调节耐旱性的调控模式，为提高农作物对干旱的适应能力提供了新的理论基础。
原文链接：
ArABIdopsis HY1-modulated Stomatal Movement: An Integrative Hub for its Functionally Associated with ABI4 in the Dehydration-induced ABA Responsiveness
原文摘要：
Heme oxygenase (HO; EC 1.14.99.3) has recently been proposed as a novel component in mediating wide ranges of the plant adaptive signaling processes. However, the physiological significance and molecular basis underlying Arabidopsis HO1 (HY1) functioning in drought tolerance remained unclear. Here we report that mutation of HY1 promoted, but over-expression this gene impaired Arabidopsis drought tolerance. This was attributed to the ABA-hypersensitive or -hyposensitive phenotypes, with the regulation of stomatal closure in particularly. However, comparative transcriptomic profile analysis showed that the induction of numerous ABA/stress-dependent genes in dehydrated-wild-type plants was differentially impaired in the hy1 mutant. In concert, ABA-induced ABI4 transcript accumulation was strengthened in hy1 mutant. Genetic analysis further identified that the hy1-associated ABA hypersensitiveness and drought tolerance were arrested in the abi4 background. Moreover, the promotion of ABA-triggered up-regulation of RbohD abundance and reactive oxygen species (ROS) levels in the hy1 mutant was almost fully blocked by the mutation of ABI4, suggesting that the HY1-ABI4 signaling in wild-type involved in stomatal closure was dependent on the RbohD-derived ROS production. However, hy1-promoted stomatal closure was not affected by nitric oxide (NO) scavenger. Correspondingly, ABA-insensitive behaviors in rbohD stomata were not affected by either the mutation of HY1 or its ectopic expression in the rbohD background, both of which responded significantly to exogenous ROS. These data indicate that HY1 functioned negatively and acted upstream of ABI4 in drought signaling, which was casually dependent on the RbohD-derived ROS in the regulation of stomatal closure.
作者：沈文飚
