Identification and Expression Analysis of WRKY Gene Family in Response to Abiotic Stress in Dendrobium catenatum.

Tingting Zhang,Jian Wang,Ying Xu,Hanggui Lai,Yadan Ding,Wengang Yu,Yang Zhou

doi:10.3389/fgene.2022.800019

Abstract

Dendrobium catenatum has become a rare and endangered medicinal plant due to habitat loss in China. As one of the most important and largest transcription factors, WRKY plays a critical role in response to abiotic stresses in plants. However, little is known regarding the functions of the WRKY family in D. catenatum. In this study, a total of 62 WRKY genes were identified from the D. catenatum genome. Phylogenetic analysis revealed that DcWRKY proteins could be divided into three groups, a division supported by the conserved motif compositions and intron/exon structures. DcWRKY gene expression and specific responses under drought, heat, cold and salt stresses were analyzed through RNA-seq data and RT-qPCR assay. The results showed that these genes had tissue-specificity and displayed different expression patterns in response to abiotic stresses. The expression levels of DcWRKY22, DcWRKY36 and DcWRKY45 were up-regulated by drought stress. Meanwhile, DcWRKY22 was highly induced by heat in roots, and DcWRKY45 was significantly induced by cold stress in leaves. Furthermore, DcWRKY27 in roots and DcWRKY58 in leaves were extremely induced under salt treatment. Finally, we found that all the five genes may function in ABA- and SA-dependent manners. This study identified candidate WRKY genes with possible roles in abiotic stress and these findings not only contribute to our understanding of WRKY family genes, but also provide valuable information for stress resistance development in D. catenatum.

Highlights

IntroductionPlants can suffer various adverse environmental stresses including drought, heat, cold, and high salt
Over their life cycle, plants can suffer various adverse environmental stresses including drought, heat, cold, and high salt
To identify specific DcWRKY genes that are potentially involved in Abscisic acid (ABA) or salicylic acid (SA) signaling pathways, we examined the transcriptional levels of these 15 genes under treatment with either 100 μM ABA or 20 μM SA by Quantitative real-time polymerase chain reaction (RT-qPCR)

Summary

Introduction

Plants can suffer various adverse environmental stresses including drought, heat, cold, and high salt. Plants can spontaneously develop a series of response mechanisms when perceiving abiotic stress, such as metabolic reconstruction, cell-tissue remodeling, and gene expression reprogramming. Stress-related transcription factors (TFs) are activated after receiving. Analysis of WRKYs in D. catenatum stress signals, acting as molecular switches to regulate the expression of their target genes by interacting with the ciselements in the gene promoters (Singh et al, 2002), and participate in the response to abiotic stress (Zhu, 2016). Most plant TFs, such as WRKY, MYB, NAC, bZIP, bHLH, and AP2/ DREB, belong to a large gene family. One of the most important and largest transcription factor families in plants is WRKY (Eulgem et al, 2000), which plays a crucial role in many metabolic regulation processes (Rushton et al, 2010)

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