Histone Deacetylase TaHDT701 Functions in TaHDA6-TaHOS15 Complex to Regulate Wheat Defense Responses to Blumeria graminis f.sp. tritici.

Pengfei Zhi,Yan Li,Cheng Chang,Xiaona Zhang,Lingyao Kong,Jiao Liu,Haoyu Li,Xiaoyu Wang,Maokai Sun

doi:10.3390/ijms21072640

Abstract

Powdery mildew disease caused by Blumeria graminis f.sp. tritici (Bgt) leads to severe economic losses in bread wheat (Triticum aestivum L.). To date, only a few epigenetic modulators have been revealed to regulate wheat powdery mildew resistance. In this study, the histone deacetylase 2 (HD2) type histone deacetylase TaHDT701 was identified as a negative regulator of wheat defense responses to Bgt. Using multiple approaches, we demonstrated that TaHDT701 associates with the RPD3 type histone deacetylase TaHDA6 and the WD40-repeat protein TaHOS15 to constitute a histone deacetylase complex, in which TaHDT701 could stabilize the TaHDA6-TaHOS15 association. Furthermore, knockdown of TaHDT701, TaHDA6, and TaHOS15 resulted in enhanced wheat powdery mildew resistance, suggesting that the TaHDT701-TaHDA6-TaHOS15 histone deacetylase complex negatively regulates wheat defense responses to Bgt. Moreover, chromatin immunoprecipitation assays revealed that TaHDT701 could function in concert with TaHOS15 to recruit TaHDA6 to the promoters of defense-related genes such as TaPR1, TaPR2, TaPR5, and TaWRKY45. In addition, silencing of TaHDT701, TaHDA6, and TaHOS15 resulted in the up-regulation of TaPR1, TaPR2, TaPR5, and TaWRKY45 accompanied with increased histone acetylation and methylation, as well as reduced nucleosome occupancy, at their promoters, suggesting that the TaHDT701-TaHDA6-TaHOS15 histone deacetylase complex suppresses wheat powdery mildew resistance by modulating chromatin state at defense-related genes.

Highlights

Blumeria graminis f.sp. tritici (Bgt) is the obligate biotrophic fungal pathogen that is capable of infecting the important crop bread wheat (Triticum aestivum L.)
To characterize the function of bread wheat histone deacetylase 2 (HD2) type histone deacetylase TaHDT701 in regulating the wheat defense responses to powdery mildew, we first identified the wheat TaHDT701 based on the protein sequence of rice OsHDT701(Os05g51830) and the genome sequence of hexaploid bread wheat
The previous study showed that overexpression of OsHDT701 enhances rice susceptibility to the biotrophic pathogen M. oryzae and hemibiotrophic pathogen Xanthomonas oryzae pv oryzae (Xoo), whereas OsHDT701-knockdown leads to increased expression of defense-related genes as well as enhanced resistance to both M. oryzae and Xoo in rice, indicating that OsHDT701 is a negative regulator of basal defense in rice [18]

Summary

Introduction

Blumeria graminis f.sp. tritici (Bgt) is the obligate biotrophic fungal pathogen that is capable of infecting the important crop bread wheat (Triticum aestivum L.). Tritici (Bgt) is the obligate biotrophic fungal pathogen that is capable of infecting the important crop bread wheat (Triticum aestivum L.). Upon landing on the aerial surface of wheat, Bgt conidia first germinate and penetrate the host cell wall to develop an intracellular feeding structure called haustorium to acquire both nutrients and water from host plant cells [1,2,3]. After successful colonization and proliferation, Bgt fungi form microcolonies and disperse conidia to infect more plants. Breeding resistant wheat varieties is a safe and effective approach to control this disease. To this end, it is vital to identify the wheat genes regulating the plant defense responses to Bgt and unravel their underlying mechanisms

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Discussion

Conclusion