菊芋适应盐逆境机理中水通道蛋白的功能

Aquaporins (AQPs) are membrane channels that facilitate the transport of water, small neutral molecules across biological membranes. In recent years that has attracted much attention due to their important roles in several plant growth and developmental processes and regulation in response to multiple environmental stimuli in the research on plant resistance mechanism. Jerusalem artichoke (Helianthus tuberosus) is an excellent resistant plant, but its resistance mechanism is as yet unknown. Our previous RNA-Seq study has shown that AQPs were abundant in Jerusalem artichoke, and genes encoding PIPs and TIPs subfamilies were significantly responsive to salt stress. We speculate that they have a significant function in the mechanism of salt tolerance of Jerusalem artichoke and play an important role. In this project, we will focus on the function of PIP1 and TIP1 subclasses. The candidate genes will be selected after the expression pattern of aquaporin genes is detected in Jerusalem artichoke. First, the subcellular localization using GFP fluorescence microscopy and the initial validation of the genetic function using Xenopus laevis oocytes expression system is investigated. The candidate genes will be overexpression in the model plants (tobacco) and Jerusalem artichoke. The salt stress tolerance analyses including phenotypic observation and physiological analysis is conducted in transgenic plants. These data could lead to a better understanding of aquaporin function in Jerusalem artichoke adaptation to salt stress. This project will establish a comprehensive and perfect research system not only for the systematic study of the function of Jerusalem artichoke AQPs, but also lay a good foundation for further in-depth study.

转运水分子及其他中性小分子的水通道蛋白在植物生长发育及环境响应中具有重要功能，近年来在植物耐逆机理研究中也倍受关注。菊芋是优秀的耐逆资源植物，但其耐逆机理研究尚不深入。前期的转录组测序结果显示菊芋水通道蛋白丰富，且有编码PIP和TIP亚族水通道蛋白的基因显著响应盐胁迫，我们推测它们在菊芋耐盐机理中具有显著功能并发挥重要作用。本项目选择菊芋水通道蛋白PIP1和TIP1作为研究对象，筛选它们的编码基因（目的基因）后进行亚细胞定位（利用绿色荧光蛋白瞬时表达技术）、基因功能初步验证（利用爪蟾卵母细胞表达系统鉴定转水活性），然后分别在模式植物（烟草）和菊芋中过表达这些目的基因获得转基因植株，通过盐胁迫处理及相应的表型观察和生理学指标测定，综合解析PIP和TIP两类水通道蛋白在菊芋耐盐机理中的功能。这些工作将为系统探讨菊芋水通道蛋白功能建立全面而完善的研究体系，为后续的深入研究奠定良好基础。

转运水分子及其他中性小分子的水通道蛋白（AQPs）在植物生长发育及环境响应中具有重要功能，近年来在植物耐逆机理研究中也倍受关注。菊芋是优秀的耐逆资源植物，但其耐逆机理研究尚不深入。前期的转录组测序结果显示菊芋水通道蛋白丰富，且有编码PIP和TIP亚族水通道蛋白的基因显著响应盐胁迫，我们推测它们在菊芋耐盐机理中具有显著功能并发挥重要作用。.本研究利用RNA-Seq数据库对菊芋AQPs家族编码基因进行了系统的生物信息学分析，经组织表达和胁迫处理筛选了关键功能基因HtPIP1-5、HtPIP1-6和HtTIP2-2。利用绿色荧光蛋白瞬时表达进行了亚细胞定位，利用爪蟾卵母细胞表达系统验证了转水功能，利用酵母系统初步验证了耐盐功能。进一步在拟南芥中过表达HtPIP1-5、HtPIP1-6和HtTIP2-2基因，结果显示显著增强了转基因拟南芥对盐和干旱胁迫的耐受能力。过表达HtPIP1-5、HtPIP1-6 和HtTIP2-2能够减少胁迫条件下转基因拟南芥的ROS积累和膜损伤，增强离子吸收，提高光合效率，从而提高了转基因拟南芥对盐和干旱胁迫的耐受性。另外，过表达HtTIP2-2的拟南芥幼苗根毛数量显著增加，也可能与抗性提高密切相关。.研究结果提供了菊芋AQPs家族信息，初步揭示了了HtPIP1-5、HtPIP1-6和HtTIP2-2在植物抗逆中的作用，丰富了菊芋耐逆机理的认知，为进一步挖掘AQPs调控抗逆性的分子机制积累了有益的基础。