Genome-Wide Identification of the Physic Nut WUSCHEL-Related Homeobox Gene Family and Functional Analysis of the Abiotic Stress Responsive Gene JcWOX5.

Yuehui Tang,Xinxin Bao,Yanyang Dong,Chunfei Xun,He Zhou,Yaxin Guan,Yuxi Guo,Jingjing Liao,Han Li,Rui Huo,Enqing Pei,Qianmiao Shen,Shen Li

doi:10.3389/fgene.2020.00670

Abstract

Plant-specific WOX transcription factors have important regulatory functions in plant development and response to abiotic stress. However, the identification and functional analysis of members of the WOX family have rarely been reported in the physic nut plant until now. Our research identified 12 WOX genes (JcWOXs) in physic nut, and these genes were divided into three groups corresponding to the ancient clade, WUS clade, and intermediate clade. Expression analysis based on RNA-seq and qRT-PCR showed that most of the JcWOX genes were expressed in at least one of the tissues tested, whereas five genes were identified as being highly responsive to drought and salt stresses. Subcellular localization analysis in Arabidopsis protoplast cells showed that JcWOX5 encoded a nuclear-localized protein. JcWOX5-overexpression plants increased sensitivity to drought stress, and transgenic plants suggested a lower proline content and CAT activity, higher relative electrolyte leakage, higher MDA content, and higher rate of water loss under drought conditions. Expression of some stress-related genes was obviously lower in the transformed rice lines as compared to their expression in wild-type rice lines under drought stress. Further data on JcWOX5-overexpressing plants reducing drought tolerance verified the potential role of JcWOX genes in responsive to abiotic stress. Collectively, the study provides a foundation for further functional analysis of JcWOX genes and the improvement of physic nut crops.

Highlights

Environmental factors, salt and drought stress, severely limit the production and distribution of many important agronomic crops worldwide
To identify the putative JcWOX genes in physic nut, a profile hidden Markov model (HMM) search against physic nut genome protein sequences was carried out using the HD domain (PF00046)
Protein sequences of all WOX family members of Arabidopsis were used as search sequences against the physic nut genome database through the online BLASTP program

Summary

Introduction

Environmental factors, salt and drought stress, severely limit the production and distribution of many important agronomic crops worldwide. To survive external extreme environment stress, plants have evolved multiple mechanisms as a defense strategy against external signals by modulating the expression of genes. Among these genes, transcription factors, such as HD-Zip, WOX, ERF, WRKY, NAC, and MYB, have clearly played a key role in regulating plant. The HLHTH structure is essential for the HD to perform its function, and the role played by the domain is extremely important (van der Graaff et al, 2009). Based on the conserved domain and similarity of full-length amino acid sequence, the researchers divided the WOX proteins into three groups, namely intermediate clade, ancient clade, and WUS clade (van der Graaff et al, 2009)

Methods

Results

Discussion

Conclusion