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Article|07 Nov 2023|OPEN
Function identification of miR159a, a positive regulator during poplar resistance to drought stress
Tiantian Fu1 ,† , Chun Wang1 ,† , Yuzhang Yang1 , Xiaoqian Yang1 , Jing Wang1 , Lichun Zhang1 , Zeqi Wang1 and Yanwei Wang,1 ,
1State Key Laboratory of Tree Genetics and Breeding, National Engineering Research Center of Tree Breeding and Ecological Restoration, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, The Tree and Ornamental Plant Breeding and Biotechnology Laboratory of National Forestry and Grassland Administration, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
*Corresponding author. E-mail: ywwang@bjfu.edu.cn
Both authors contributed equally to the study.

Horticulture Research 11,
Article number: uhad221 (2024)
doi: https://doi.org/10.1093/hr/uhad221
Views: 49

Received: 05 May 2023
Accepted: 24 Oct 2023
Published online: 07 Nov 2023

Abstract

Drought seriously affects the growth and development of plants. MiR159 is a highly conserved and abundant microRNA family that plays a crucial role in plant growth and stress responses. However, studies of its function in woody plants are still lacking. Here, the expression of miR159a was significantly upregulated after drought treatment in poplar, and the overexpression of miR159a (OX159a) significantly reduced the open area of the stomata and improved water-use efficiency in poplar. After drought treatment, OX159a lines had better scavenging ability of reactive oxygen species and damage of the membrane system was less than that in wild-type lines. MYB was the target gene of miR159a, as verified by psRNATarget prediction, RT–qPCR, degradome sequencing, and 5′ rapid amplification of cDNA ends (5′ RACE). Additionally, miR159a–short tandem target mimic suppression (STTM) poplar lines showed increased sensitivity to drought stress. Transcriptomic analysis comparing OX159a lines with wild-type lines revealed upregulation of a series of genes related to response to water deprivation and metabolite synthesis. Moreover, drought-responsive miR172d and miR398 were significantly upregulated and downregulated respectively in OX159a lines. This investigation demonstrated that miR159a played a key role in the tolerance of poplar to drought by reducing stomata open area, increasing the number and total area of xylem vessels, and enhancing water-use efficiency, and provided new insights into the role of plant miR159a and crucial candidate genes for the molecular breeding of trees with tolerance to drought stress.