WRKY genes family study reveals tissue-specific and stress-responsive TFs in wild potato species

Clizia Villano,Vincenzo D’Amelia,Salvatore Esposito,Daniela Alioto,Raffaele Garramone,Domenico Carputo,Riccardo Aversano,Astolfo Zoina

doi:10.1038/s41598-020-63823-w

Abstract

Wild potatoes, as dynamic resource adapted to various environmental conditions, represent a powerful and informative reservoir of genes useful for breeding efforts. WRKY transcription factors (TFs) are encoded by one of the largest families in plants and are involved in several biological processes such as growth and development, signal transduction, and plant defence against stress. In this study, 79 and 84 genes encoding putative WRKY TFs have been identified in two wild potato relatives, Solanum commersonii and S. chacoense. Phylogenetic analysis of WRKY proteins divided ScWRKYs and SchWRKYs into three Groups and seven subGroups. Structural and phylogenetic comparative analyses suggested an interspecific variability of WRKYs. Analysis of gene expression profiles in different tissues and under various stresses allowed to select ScWRKY045 as a good candidate in wounding-response, ScWRKY055 as a bacterial infection triggered WRKY and ScWRKY023 as a multiple stress-responsive WRKY gene. Those WRKYs were further studied through interactome analysis allowing the identification of potential co-expression relationships between ScWRKYs/SchWRKYs and genes of various pathways. Overall, this study enabled the discrimination of WRKY genes that could be considered as potential candidates in both breeding programs and functional studies.

Highlights

Plants experience environmental constrains and pathogen attacks during their life
The phylogenetic analysis of seven AtWRKY proteins randomly selected as representative of each WRKY Group and all S. commersonii and S. chacoense WRKY proteins revealed ScWRKY and SchWRKY classification in three large Groups corresponding to Group I, II and III (Fig. 1), with the exception of nine proteins in S. commersonii (ScWRKY047,ScWRKY051, ScWRKY052, ScWRKY055, ScWRKY085, ScWRKY087a, ScWRKY087b, ScWRKY088 and ScWRKY089) and eight proteins in S. chacoense (SchWRKY047, SchWRKY051, SchWRKY052, SchWRKY056, SchWRKY057, SchWRKY085, SchWRKY088 and SchWRKY089), that were not assigned to any Group (Table 1)
In S. commersonii, the “WRKYGQK” pattern was highly conserved in 69 ScWRKYs, while five variations were observed in the other proteins (“WGKYGQK”, “WRWLKCG”, “WSKYGQK”, “WRKCGQK”, “WRKYGMK”)

Summary

Introduction

Plants experience environmental constrains and pathogen attacks during their life. Being sessile organisms, their survival depends on the ability to properly and promptly reprogram cellular networks. It has been confirmed that WRKYs base defence mechanism to abiotic stresses and play a key role in cross-talk pathway networks between plant response and development[5,6]. Studies addressed to mine sequence divergences or to identify gene expression differences in WRKYs of www.nature.com/scientificreports cultivated and wild species are increasing. Such investigations may pave the way into exploiting these regulators for breeding purposes. Dellagi et al.[23] identified StWRKY1 as a good candidate for functional studies, and Shahzad et al.[24] overexpressed it in potato They provided evidence that StWRKY1 acts as positive regulator of biotic and abiotic stress resistance through the activation of basal defence networks. Through the data here presented, the work aims to give a picture of the potato wild WRKY members, their nature and the complexity of their responses to unfavourable situations

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Discussion

Conclusion