Identification and characterization of the BZR transcription factor family and its expression in response to abiotic stresses in Zea mays L.

Abstract

Brassinosteroids (BRs) are plant specific steroidal hormones that play diverse roles in regulating a broad spectrum of plant growth and developmental processes, as well as, in responding to various biotic and abiotic stresses. Extensive research over the years has established stress-impact-mitigating role of BRs and associated compounds in different plants exposed to various abiotic and biotic stresses, suggesting the idea that they may act as immunomodulators, thus opening new approaches for plant resistance against hazardous environmental conditions. In this research the characterization of the transcriptional response of 11 transcription factors (TFs) belonging to BRASSINAZOLE-RESISTANT 1 (BZR1) TF family of Zea mays L. was analyzed in seedlings subjected to different stress conditions. Being important regulators of the BR synthesis, BZR TFs might have stress resistance related activities. However, no stress resistance related functional study of BZR TFs has been reported in maize so far. In silico analyses of the selected 11 TFs validated the features of their protein domains, where the highest degree of similarity observed with recognized BZR TFs of rice and Sorghum bicolor. Additionally, we investigated the organ-specific expression of 11 ZmBZR in maize seedlings. Five of them did not show any transcript accumulation, suggesting that ZmBZR expression might be regulated in a manner dependent on plant developmental stage. For the remaining six ZmBZR, their ubiquitous expression in the whole plant indicates they could function as growth regulators during maize development. More importantly, in response to various stress conditions, the spatial transcript accumulation of all ZmBZR varies along the plant. All six ZmBZR showed up-regulation against N starvation, hypoxia and salt stress. On the contrary, heat stress clearly down-regulated gene expression of all ZmBZR analysed. Consistently with the expression results, the distribution of stress-related cis-acting elements in the promoter of these genes inferred that the maize BZR TFs might play some roles in regulating the expression of the corresponding genes in response to multifarious stresses. In conclusion, these data reveal that BZR TFs have stress signaling activity in maize, in addition to their confirmed role in regulating plant physiology and morphology.

A Chinese White Pear (Pyrus bretschneideri) BZR Gene PbBZR1 Act as a Transcriptional Repressor of Lignin Biosynthetic Genes in Fruits

“…In our study, six, eight, eight, twelve and thirteen BZR-coding protein sequences were identified in F.vesca , P. mume , P. persica , P. communis and P. bretschneideri , respectively ( Table S1 ). Compared with other gene families in the studied species, the BZR gene family is of relatively small size, which is consistent with the previous studies such as six, six, eleven and fifteen BZR genes in A. thaliana , E. grandis , Z. mays and B. rapa , respectively ( Saha et al, 2015 ; Fan et al, 2018 ; Manoli et al, 2018 ; Yu et al, 2018 ). Interestingly, the numbers of BZR genes have a certain degree of expansion in both P. communis and P. bretschneideri , when compared with those in F. vesca , P. mume and P. persica .…”

“…As previously reported, the members of the BZR gene family were found to be involved in the regulation of various processes in plants, and the positive roles of the BZR genes in BR signal transduction have been well studied in plants, such as A. thaliana , Brassica rapa , Eucalyptus grandis and Zea mays ( Clouse et al, 1996 ; Li and Chory, 1997 ; Ye et al, 2010 ; Clouse, 2011 ; Saha et al, 2015 ; Fan et al, 2018 ; Manoli et al, 2018 ; Yu et al, 2018 ). However, no systematic, in-depth study of the BZR gene family has been reported in five Rosaceae species, including F. vesca , P. mume , P. persica , P. communis , and P. bretschneideri .…”

Exploring the Brassinosteroid Signaling in Monocots Reveals Novel Components of the Pathway and Implications for Plant Breeding

“…Expression of the other six genes was ubiquitous. Moreover, the ZmBZR1 genes showed differential expression pattern in response to abiotic stresses and light signal [93,94].…”

Genome-Wide Identification, Characterization, and Expression Profiling of the Legume BZR Transcription Factor Gene Family

“…As some of the most important crops worldwide for both humans and domestic animals, further efforts should be made for mining and characterizing genes related to legume growth, development, and stress responses ( Dixon and Sumner, 2003 ; Graham and Vance, 2003 ). The BZR genes encode important TFs that function in the regulation of plant growth and development and the BZR-mediated abiotic stress response and have been identified and characterized in detail in only a few plant species, including A. thaliana , Brassica rapa , and Zea mays ( Yin et al, 2005 ; Saha et al, 2015 ; Manoli et al, 2018 ). Some predictions in public databases (such as iTAK and PlantTFDB) resulting from genome-scale automatic annotation pipelines have resulted in identification of new BZR genes ( Zheng et al, 2016 ; Jin et al, 2017 ); however, the genome-wide identification, characterization, and expression profile analysis of BZR gene evolution and function in legumes has yet to be completed.…”