Liu Ying-Li, Wang Li-Juan, Li Yu, Guo Ying-Hua, Cao Yuan, Zhao Shu-Tang
State Key Laboratory of Tree Genetics and Breeding, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China.
Co-innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China.
Front Plant Sci. 2021 Jun 4;12:686024. doi: 10.3389/fpls.2021.686024. eCollection 2021.
Rab GTPases are the subfamily of the small guanosine triphosphate (GTP)-binding proteins which participated in the regulation of various biological processes. Recent studies have found that plant Rabs play some specific functions. However, the functions of in xylem development in trees remain unclear. In this study, functional identification of in was performed. Quantitative reverse transcription PCR (qRT-PCR) results showed that was highly accumulated in stems, especially in phloem and xylem tissues. Overexpression of in poplar enhanced programmed cell death (PCD) and increased the growth rate and the secondary cell wall (SCW) thickness. Quantitative analysis of monosaccharide content showed that various monosaccharides were significantly increased in secondary xylem tissues of the overexpressed lines. Flow cytometry analysis revealed that the number of apoptotic cells in lines is more than a wild type (WT), which indicated that may play an important role in PCD. Further studies showed that overexpression of increased the expression level of genes involved in SCW biosynthesis, PCD, and autophagy. Collectively, the results suggest that plays a positive role in promoting the xylem development of poplar.
Rab鸟苷三磷酸酶（GTP酶）是小GTP结合蛋白的一个亚家族，参与多种生物学过程的调控。最近的研究发现，植物Rab蛋白具有一些特定功能。然而，其在树木木质部发育中的功能仍不清楚。在本研究中，对其在杨树中的功能进行了鉴定。定量逆转录PCR（qRT-PCR）结果表明，该基因在茎中高度积累，尤其是在韧皮部和木质部组织中。在杨树中过表达该基因可增强程序性细胞死亡（PCD），提高生长速率并增加次生细胞壁（SCW）厚度。单糖含量的定量分析表明，过表达株系的次生木质部组织中各种单糖显著增加。流式细胞术分析显示，该基因过表达株系中的凋亡细胞数量多于野生型（WT），这表明该基因可能在PCD中起重要作用。进一步研究表明，过表达该基因可提高参与SCW生物合成、PCD和自噬的基因的表达水平。总体而言，结果表明该基因在促进杨树木质部发育中起积极作用。
