Genome-Wide Investigation of Heat Shock Transcription Factor Family in Wheat (Triticum aestivum L.) and Possible Roles in Anther Development.

Jiali Ye,Qi Liu,Lingli Zhang,Xiyue Song,Wei Li,Gan Hu,Xuetong Yang

doi:10.3390/ijms21020608

Abstract

Heat shock transcription factors (HSFs) play crucial roles in resisting heat stress and regulating plant development. Recently, HSFs have been shown to play roles in anther development. Thus, investigating the HSF family members and identifying their protective roles in anthers are essential for the further development of male sterile wheat breeding. In the present study, 61 wheat HSF genes (TaHsfs) were identified in the whole wheat genome and they are unequally distributed on 21 chromosomes. According to gene structure and phylogenetic analyses, the 61 TaHsfs were classified into three categories and 12 subclasses. Genome-wide duplication was identified as the main source of the expansion of the wheat HSF gene family based on 14 pairs of homeologous triplets, whereas only a very small number of TaHsfs were derived by segmental duplication and tandem duplication. Heat shock protein 90 (HSP90), HSP70, and another class of chaperone protein called htpG were identified as proteins that interact with wheat HSFs. RNA-seq analysis indicated that TaHsfs have obvious period- and tissue-specific expression patterns, and the TaHsfs in classes A and B respond to heat shock, whereas the C class TaHsfs are involved in drought regulation. qRT-PCR identified three TaHsfA2bs with differential expression in sterile and fertile anthers, and they may be candidate genes involved in anther development. This comprehensive analysis provides novel insights into TaHsfs, and it will be useful for understanding the mechanism of plant fertility conversion.

Highlights

The heat shock response is common in plants where a series of stress responses are generated under heat stress [1]
As a consequence of heat stress, plant heat shock elements (HSEs) present in the promoter regions upstream of the heat shock protein (HSP) genes are recognized by the activated heat shock transcription factors (HSFs), and they induce the transcription of Hsp genes as molecular chaperones to help refold, assemble, distribute, and degrade related proteins, as well as repairing damaged proteins and maintaining cell survival [2,3,4]
The newly constructed wheat-specific hidden Markov model (HMM) file was used to search the whole wheat protein sequences and 94 candidate Hsfs were obtained, which were consistent with the wheat candidate Hsfs obtained by aligning with Arabidopsis and rice Hsfs

Summary

Introduction

The heat shock response is common in plants where a series of stress responses are generated under heat stress [1]. A typical HSF has three components comprising the N-terminal DNA-binding domain (DBD), oligomeric domain (OD), and nuclear localization signal (NLS). Some HSFs have a C-terminal activation domain (CTAD) and nuclear export signal (NES) [5]. DBDs are located at the N-terminus of HSFs and they are highly conserved regions with three helical structures (H1, H2, and H3) and four inverted parallel β-sheets (β1, β2, β3, and β4) [6]. The synergy between the NLS and NES maintains the cell balance, thereby allowing plant HSFs to be freely distributed in the cytoplasm and nucleus [10]. Together with the NES, the CTAD acidic amino acid (AHA) motifs serve as a type-specific region in the C-terminus of class A HSFs in plants, which is characterized by aromatic and large hydrophobic amino acids [11]. The B and C class HSFs have no activation functions due to the lack of an AHA domain [5]

Methods

Results

Conclusion