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Article|21 Nov 2022|OPEN
Overexpression of miR390b promotes stem elongation and height growth in Populus 
Qiaofang Shi1,2 , Dongdong Tian1,3 , Jieyu Wang1,2 , Aoli Chen1 , Yuqing Miao1 , Yiming Chen1,2 and Jun Li1,2 , Xiaomeng Wu1 , Bo Zheng1,2 , Wenwu Guo1 , Xueping Shi,1,2 ,
1Key Laboratory of Horticultural Plant Biology of Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China
2Poplar Research Center, Huazhong Agricultural University, Wuhan 430070, China
3Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao 266101, China
*Corresponding author. E-mail: xpshi@mail.hzau.edu.cn

Horticulture Research 10,
Article number: uhac258 (2023)
doi: https://doi.org/10.1093/hr/uhac258
Views: 305

Received: 07 Jul 2022
Accepted: 18 Nov 2022
Published online: 21 Nov 2022

Abstract

MicroRNA390 (miR390) is involved in plant growth and development by down-regulating the expression of the downstream genes trans-acting short interfering RNA3 (TAS3) and AUXIN RESPONSE FACTORs (ARFs). There is a scarcity of research on the involvement of the miR390-TAS3-ARFs pathway in the stem development of Populus. Here, differentially expressed miRNAs during poplar stem development were screened by small RNA sequencing analysis, and a novel function of miR390b in stem development was revealed. Overexpression of miR390b (OE-miR390b) resulted in a large increase in the number of xylem fiber cells and a slight decrease in the cell length at the longitudinal axis. Overall increases in stem elongation and plant height were observed in the OE-miR390b plants. According to transcriptome sequencing results and transient co-expression analysis, TAS3.1 and TAS3.2 were identified as the target genes of miR390 in poplar and were negatively regulated by miR390 in the apex. The transcription levels of ARF3.2 and ARF4 were significantly repressed in OE-miR390b plants and strongly negatively correlated with the number of xylem fiber cells along the longitudinal axis. These findings indicate that the conserved miR390-TAS3-ARFs pathway in poplar is involved in stem elongation and plant height growth.