OsTGA2 confers disease resistance to rice against leaf blight by regulating expression levels of disease related genes via interaction with NH1

Abstract

How plants defend themselves from microbial infection is one of the most critical issues for sustainable crop production. Some TGA transcription factors belonging to bZIP superfamily can regulate disease resistance through NPR1-mediated immunity mechanisms in Arabidopsis. Here, we examined biological roles of OsTGA2 (grouped into the same subclade as Arabidopsis TGAs) in bacterial leaf blight resistance. Transcriptional level of OsTGA2 was accumulated after treatment with salicylic acid, methyl jasmonate, and Xathomonas oryzae pv. Oryzae (Xoo), a bacterium causing serious blight of rice. OsTGA2 formed homo- and hetero-dimer with OsTGA3 and OsTGA5 and interacted with rice NPR1 homologs 1 (NH1) in rice. Results of quadruple 9-mer protein-binding microarray analysis indicated that OsTGA2 could bind to TGACGT DNA sequence. Overexpression of OsTGA2 increased resistance of rice to bacterial leaf blight, although overexpression of OsTGA3 resulted in disease symptoms similar to wild type plant upon Xoo infection. Overexpression of OsTGA2 enhanced the expression of defense related genes containing TGA binding cis-element in the promoter such as AP2/EREBP 129, ERD1, and HOP1. These results suggest that OsTGA2 can directly regulate the expression of defense related genes and increase the resistance of rice against bacterial leaf blight disease.

Expression Analysis of MaTGA8 Transcription Factor in Banana and Its Defence Functional Analysis by Overexpression in Arabidopsis

“…Among rice bZIP transcription factors, OsTGA2 could interact with rice NPR1-homolog proteins (NHs). Overexpression of OsTGA2 increased the resistance of rice to bacterial leaf blight [10]. Studies have shown that VvTGA1 can provide the DNA binding capacity required by VvNPR1 to activate the VvPR gene, and the interaction between VvNPR1 and VvTGA1 may be the cause of the effective disease resistance induced by β-aminobutyric acid (BABA) [42].…”

“…For example, ten TGA transcription factors have been isolated and identified from Arabidopsis, which can be divided into five categories; members of groups I, II, and III are widely involved in the disease resistance of plants [3][4][5], and members of groups IV and V play a role in floral organ development [6][7][8]. To date, the TGA transcription factor has been isolated and identified in many plants, including papaya, rice, soybean, and strawberry [9][10][11][12]. It has been confirmed that the TGA transcription factor is involved in the process of drought resistance, salt tolerance, and detoxification, and promotes root nitrate absorption [13][14][15][16][17].…”

OsbZIP81, A Homologue of Arabidopsis VIP1, May Positively Regulate JA Levels by Directly Targetting the Genes in JA Signaling and Metabolism Pathway in Rice

“…JAs are lipid-derived compounds that act as key signals in plant stress responses and development [9,65]. Some bZIP members in plants are also involved in herbivore and pathogen resistance through JA signaling and the metabolism pathway [65,66,67]. JA and related compounds ubiquitously exist in land plants and function in plant development and responses to numerous stresses [5,9,68,69].…”

A mini-TGA protein, lacking a functional DNA-binding domain, modulates gene expression through heterogeneous association with transcription factors

“…Although the results obtained in Arabidopsis provide a molecular framework for understanding the role of TGAs in plant immunity, we know much less about their function in crops. The involvement of TGAs in biotic stress response has been reported in several species, including rice 17 , soybean 18 , strawberry 19 , tobacco 9 , and tomato 20 . Potato ( Solanum tuberosum L.) is one of the most widely grown crops 21 and tuber production is severely threatened by pathogen infections.…”