作者：Shaofeng Li^a , Yaoxiang Zhang^a , Changjun Ding^b , Xu Gao^a , Ran Wang^a , Wenjuan Mo^a , Fuling lv^a, Shaoli Wang^a , Liang Liu^a , Zhimin Tang^a , Hua Tian^a , Jianhui Zhang^c , Bingyu Zhang^b, Qinjun Huang^b , Mengzhu Lu^b , Ta-na Wuyun^d , Zanmin Hu^e , Yongxiu Xia^a，*, Xiaohua Su^b，*

单位：a. Experimental Center of Forestry in North China, Chinese Academy of Forestry; b. State Key Laboratory of Tree Genetics and Breeding, Research Institute of Forestry, Chinese Academy of Forestry; c. Department of Pharmaceutical Science, Biomanufacturing Research Institute and Technology Enterprise, North Carolina Central University; d. Non-timber Forest Research and Development Center, Chinese Academy of Forestry; e. Institute of Genetics and Developmental Biology, Chinese Academy of Sciences.

期刊：Journal of Plant Physiology，2019，233：58-72

基金：National Natural Science Foundation of China (Grant No. 31770705);the Open Fund of State Key Laboratory of Tree Genetics and Breeding (Chinese Academy of Forestry) (Grant No. TGB2013002);and the National Key Program on Transgenic Research (Grant No. 2018ZX08020002).

摘要：Proline-rich protein (PRP) is a plant cell wall associated protein. Its distinct patterns of regulation and localization studied in a number of plants indicate that it may play important roles in growth and development. However, the mechanism of how these genes control secondary cell wall development in tree species is largely unknown. Here, we report that a Populus deltoides (Marsh.) proline-rich protein gene PdPRP was preferentially expressed in immature/mature phloem and immature xylem in P. deltoides. PdPRP overexpression increased poplar plant height and diameter as well as the radial width of the phloem and xylem regions, facilitated sec-ondary wall deposition, and induced expression of genes related to microfibril angle (MFA) and secondary wall biosynthesis. Downregulation of PdPRP retarded poplar growth, decreased the radial width of the secondary phloem and secondary xylem regions, reduced secondary wall thickening in fibers and vessels, and decreased the expression of genes related to MFA and secondary wall biosynthesis. These results suggest that PdPRP might positively regulate secondary cell wall formation by promoting secondary wall thickening and expansion in poplar. PdPRP-overexpressing poplar had a lower MFA, indicating that PdPRP may be useful for improving wood stiffness and properties in plants. Together, our results demonstrate that PdPRP is aproline-rich protein asso-ciated with cell wall development, playing a critical role in regulating secondary cell wall formation in poplar.

关键词：Molecular mechanisms;Vascular growth;PdPRP;Populus deltoids;Secondary wall formation