TaMYB29: A Novel R2R3-MYB Transcription Factor Involved in Wheat Defense Against Stripe Rust

Abstract

Members of the R2R3-MYB transcription factor superfamily have been implicated in plant development, improved disease resistance, and defense responses to several types of stresses. To study the function of TaMYB29 transcription factor—a member of the R2R3-MYB superfamily—in response to an avirulent race of stripe rust pathogen, Puccinia striiformis f. sp. tritici (Pst), we identified and cloned the TaMYB29 gene from wheat cultivar (cv.) AvS+Yr10 following infection with Pst. The TaMYB29 protein, comprising 261 amino acids, contains two highly conserved MYB domains. We first showed that TaMYB29 is a transcription factor, whose transcriptional levels are significantly induced by salicylic acid (SA), abscisic acid (ABA), jasmonic acid (JA), ethylene (ET), and Pst. The results showed that TaMYB29 is involved in the wheat response to stipe rust. The overexpression of the TaMYB29 gene resulted in the accumulation of reactive oxygen species (ROS) and pathogen-independent cell death in Nicotiana benthamiana leaves. The silencing of TaMYB29 gene in wheat cv. AvS+Yr10, containing the stripe rust resistance gene Yr10, promoted hyphae growth, significantly downregulated the expression of pathogenesis-related (PR) genes, and substantially reduced the wheat resistance to Pst compared with the non-silenced control. In addition, the accumulation of hydrogen peroxide (H2O2) significantly decreased, and the activity of catalase, an enzyme required for H2O2 scavenging, was elevated. Altogether, TaMYB29 positively regulates the defense response against stripe rust in wheat AvS+Yr10 by enhancing H2O2 accumulation, PR gene expression, and SA signaling pathway-induced cell death. These results provide new insights into the contribution of TaMYB29 to the defense response against rust pathogens in wheat.

Harnessing genetic resistance to rusts in wheat and integrated rust management methods to develop more durable resistant cultivars

“…A member of the R2R3-MYB superfamily, TaMYB29 have two highly conserved MYB domains and it regulates crosstalk across signaling pathways in wheat's response to stripe rust. The expression of TaMYB29 was significantly upregulated by Pst infection, salicylic acid, jasmonic acid, ethylene and abscisic acid treatment, indicating its involvement in wheat defense response to Pst (Zhu et al, 2021). Compared to non-silenced plants, knockdown of TaMYB29 gene enhanced hyphal growth, substantially downregulated expression of pathogenesis-related genes and significantly reduced wheat resistance to Pst (Zhu et al, 2021).…”

“…The expression of TaMYB29 was significantly upregulated by Pst infection, salicylic acid, jasmonic acid, ethylene and abscisic acid treatment, indicating its involvement in wheat defense response to Pst (Zhu et al, 2021). Compared to non-silenced plants, knockdown of TaMYB29 gene enhanced hyphal growth, substantially downregulated expression of pathogenesis-related genes and significantly reduced wheat resistance to Pst (Zhu et al, 2021). Therefore, these findings demonstrated that TaMYB29 serves an indispensable role in wheat defense response to Pst through the regulation of crosstalk between multiple signaling pathways.…”

“…There are roughly 52 amino acid residues in total in the MYB domain, which adopts a helix-turn-helix conformation and intercalates into the primary groove of DNA (Dubos et al, 2010;Al-Attala et al, 2014). Members of the R2R3-MYB transcription factor superfamily were speculated to play a vital role in plant development, defense responses to abiotic and biotic stresses as well as enhanced disease resistance (Zhu et al, 2021). A member of the R2R3-MYB superfamily, TaMYB29 have two highly conserved MYB domains and it regulates crosstalk across signaling pathways in wheat's response to stripe rust.…”

The Pathogen-Induced MATE Gene TaPIMA1 Is Required for Defense Responses to Rhizoctonia cerealis in Wheat

“…For example, heightened expression of the defense-associated genes, such as TaSTT3b-2B , TaRCR1 , and Ta PIE1 , confer enhanced resistance to R. cerealis in transgenic wheat [ 6 , 11 , 23 , 24 ]. Conversely, silencing of these genes down-regulated the expression of defense genes and weakened resistance of wheat to sharp eyespot disease [ 10 , 24 , 36 ]. Herein, the transcriptional levels of PR1.2 , PR10 , Defensin , and Chitinase3 were significantly decreased in TaPIMA1 -silenced wheat plants, which is consistent with the performance of wheat to sharp eyespot ( Figure 5 ).…”

“…Similarly, TaPIMP1 positively regulates defense responses to Bipolaris sorokiniana and drought stress through the ABA–SA signaling pathway in wheat [ 35 ]. TaMYB29 overexpression enhances resistance to stripe rust by boosting H 2 O 2 accumulation, PR genes expression, and SA signaling in wheat [ 36 ]. Therefore, various defense-associated genes perform their functions in a highly coordinated manner through complex phytohormone signaling networks in plants.…”