TGA factors promote plant root growth by modulating redox homeostasis or response

Abstract

To identify novel regulators of stem cell renewal, we mined an existing but little explored cell type‐specific transcriptome dataset for the Arabidopsis root. A member of the TGA family of transcription factors, TGA8, was found to be specifically expressed in the quiescent center (QC). Mutation in TGA8 caused a subtle root growth phenotype, suggesting functional redundancy with other TGA members. Using a promoter::HGFP transgenic approach, we showed that all TGA factors were expressed in the root, albeit at different levels and with distinct spatial patterns. Mutant analyses revealed that all TGA factors examined contribute to root growth by promoting stem cell renewal, meristem activity, and cell elongation. Combining transcriptome analyses, histochemical assays, and physiological tests, we demonstrated that functional redundancy exists among members of clades II and V or those in clades I and III. These two groups of TGA factors act differently, however, as their mutants responded to oxidative stress differently and quantitative reverse transcription polymerase chain reaction assays showed they regulate different sets of genes that are involved in redox homeostasis. Our study has thus uncovered a previously unrecognized broad role and a mechanistic explanation for TGA factors in root growth and development.

The Grapevine Transcription Factor VvTGA8 Enhances Resistance to White Rot via the Salicylic Acid Signaling Pathway in Tomato

“…A study has shown that the overexpression of MaTGA8 from banana significantly enhances resistance to Fusarium oxysporum TR4 in A. thaliana [38]. In addition, TGA8 promotes root growth by promoting stem cell regeneration, meristem activity, and cell elongation in A. thaliana [27]. This study provides the first evidence for the role of VvTGA8 in resistance in grapevine.…”

“…The SA signaling pathway induced by pathogens activates the kinase activity of BIN2, which in turn promotes the phosphorylation of TGA3, forming a positive feedback mechanism and contributing to cascade activity related to immune signals and disease resistance in A. thaliana [24]. Nevertheless, a growing number of reports indicate that clades IV and V were also involved in the regulation of defense response [25][26][27]. For example, A. thaliana TGA2, 5, 6, and 8 were found to have a common role in defense responses [27].…”

“…Nevertheless, a growing number of reports indicate that clades IV and V were also involved in the regulation of defense response [25][26][27]. For example, A. thaliana TGA2, 5, 6, and 8 were found to have a common role in defense responses [27]. However, the mechanisms underlying the function of TGAs in white rot resistance in grapevines remain unclear.…”

Genome-Wide Identification of the TGA Gene Family and Expression Analysis under Drought Stress in Brassica napus L.

“…AtTGA09 , AtTGA10 , and AtPAN play an important role in regulating the development of flower organs [ 54 , 55 , 56 ]. Moreover, studies have indicated a correlation between AtPAN and root growth [ 57 ]. It is speculated that the remaining BnTGA genes belonging to the same subgroup as AtTGA09 , AtTGA10 , and AtPAN may be related to flower organ development.…”