Formation, chemical composition and function of suberin in poplar (Populus trichocarpa) roots

在本项目中，我们将首次阐明毛白杨根质外体屏障的生物合成、化学成分、功能及其在耐旱耐盐中的意义。这种方法包括：(I)鉴定对非生物胁迫(盐分和干旱)响应的杨树根中组织特异的Suberin沉积的特征，(Ii)研究杨树根对非生物胁迫的组织特异性(内皮层和外皮)基因表达(转录)，以确定Suberin生物合成的关键基因，(Iii)化学分析杨树根Suberin的组成及其对非生物胁迫的修饰，(Iv)表征杨树根径向水分和溶质运输以及对非生物胁迫的响应变化，以及(V)产生转基因杨树品系，该项目的特点是参与根硫化的基因的过度表达或下调，以及随后这些转基因品系对非生物胁迫的解剖、化学和运输特性的表征。该项目将首次深入了解一种重要的经济树种的根硫化及其对干旱和盐分胁迫的适应。深入了解杨树根系对干旱、盐分等非生物胁迫因子的响应，可以在根质外体障碍水平上提高杨树的抗逆性，为今后培育更耐逆的杨树品种奠定基础。

In the project suggested here we will for the first time elucidate the biosynthesis, chemical composition and function of suberized apoplastic barriers in poplar (Populus trichocarpa) roots and their significance in drought and salt tolerance. This approach includes:(i) characterization of root anatomy to identify tissue specific suberin deposition in roots in response to abiotic stress (salt and drought),(ii) investigation of tissue specific (endodermal and exodermal) gene expression (transcriptomics) in poplar roots in response to abiotic stress in order to identify key genes for suberin biosynthesis,(iii) chemical analysis of poplar root suberin composition and its modifications in response to abiotic stress,(iv) characterization of radial water and solute transport of poplar roots and changes in response to abiotic stress and finally(v) generation of transgenic poplar lines, characterized by over-expression or down-regulation of genes involved in root suberization and subsequent characterization of anatomy, chemistry and transport properties of these transgenic lines in response to abiotic stress.This project will give first insights into root suberization and adaptation to drought and salt stress of an economically important tree species. Improved knowledge how poplar roots respond to abiotic stress factors like drought and salt on the level of suberized apoplastic barriers in roots could help in future in poplar breeding to achieve more stress tolerant cultivars.