The WRKY transcription factor PlWRKY65 enhances the resistance of Paeonia lactiflora (herbaceous peony) to Alternaria tenuissima

Xue Wang; Junjie Li; Jing Guo; Qian Qiao; Xianfeng Guo; Yan Ma

doi:10.1038/s41438-020-0267-7

The WRKY transcription factor PlWRKY65 enhances the resistance of Paeonia lactiflora (herbaceous peony) to Alternaria tenuissima

Hortic Res. 2020 Apr 1:7:57. doi: 10.1038/s41438-020-0267-7. eCollection 2020.

Authors

Xue Wang^#¹, Junjie Li^#¹, Jing Guo^{1

2}, Qian Qiao³, Xianfeng Guo^{1

2}, Yan Ma^{1

2}

Affiliations

¹ 1College of Forestry, Shandong Agricultural University, No. 61, Daizong Road, 271018 Tai'an, Shandong China.
² Shandong Provincial Research Center of Demonstration Engineering Technology for Urban and Rural Landscapes, 271018 Tai'an, Shandong China.
³ Shandong Institute of Pomology, 271000 Tai'an, Shandong China.

^# Contributed equally.

Abstract

In this study, the disease resistance gene PlWRKY65 was isolated from the leaves of Paeonia lactiflora and analyzed by bioinformatics methods, and the localization of the encoded protein was explored. Quantitative real-time PCR (qRT-PCR) was also used to explore the response of this gene to Alternaria tenuissima. The results showed that the gene sequence contained multiple cis-acting elements involved in the response to hormone signaling molecules belonging to the IIe subgroup of the WRKY family, and the encoded proteins were located in the nucleus. The PlWRKY65 gene has a positive regulatory effect on A. tenuissima infection. After silencing the PlWRKY65 gene via virus-induced gene silencing (VIGS), it was found that the gene-silenced plants were more sensitive to A. tenuissima infection than the wild plants, exhibiting more severe infection symptoms and different degrees of changes in the expression of the pathogenesis-related (PR) genes. In addition, we showed that the endogenous jasmonic acid (JA) content of P. lactiflora was increased in response to A. tenuissima infection, whereas the salicylic acid (SA) content decreased. After PlWRKY65 gene silencing, the levels of the two hormones changed accordingly, indicating that PlWRKY65, acting as a disease resistance-related transcriptional activator, exerts a regulatory effect on JA and SA signals. This study lays the foundation for functional research on WRKY genes in P. lactiflora and for the discovery of candidate disease resistance genes.

Keywords: Plant stress responses; RNAi.