Wheat F-box Protein TaFBA1 Positively Regulates Plant Drought Tolerance but Negatively Regulates Stomatal Closure

Abstract

The phytohormone abscisic acid (ABA) regulates plant growth and development, as well as responses to various stresses, such as salt and drought. The wheat TaFBA1 gene, which encodes an F-box protein, was previously identified in our laboratory by homologous cloning. We previously found that TaFBA1 expression was induced by ABA and drought stress. In this study, wild-type (WT), TaFBA1 over-expressing (OEs), TaFBA1 homologous gene mutants, and TaFBA1 recovery (Rs) Arabidopsis plants were used. We found that the germination rate, the cotyledon greening rate, the root length, and the photosynthetic performance of TaFBA1 OE plants were better than those of WT under drought and ABA conditions, but mutant plants showed the opposite trend, and overexpression of TaFBA1 in mutants can recover their phenotype. In addition, TaFBA1 was found to be a negative regulator of ABA-induced stoma movement; mRNA transcription of certain ABA signaling-related genes was lower in TaFBA1 OE plants than in WT plants following ABA treatment. Further, we found that TaFBA1 can interact with RCAR1 (an ABA receptor) and ABI5. BiFC assay showed that TaFBA1 may interact with RCAR1 in the plasma membrane. In addition, accumulation of ROS and MDA in TaFBA1 OE plants was lower than that in the WT plants after ABA and drought treatments. Based on these results, we suggest that TaFBA1-regulated ABA insensitivity may be dependent on regulating ABA-mediated gene expression through interacting with RCAR1 and ABI5. Increased antioxidant competence and decreased ROS accumulation may be an important mechanism that underlies improved drought tolerance in TaFBA1 OE plants.

A comprehensive phenotypic and genomic characterization of Ethiopian sorghum germplasm defines core collection and reveals rich genetic potential in adaptive traits

“…The top most significantly associated SNP (S8_60346825), on chromosome 8, was located 2 kb from Srp40 (Serine/Arginine‐rich proteins ) which was previously reported to contribute to plant‐specific forms of developmental regulation and environmental adaptation (Califice, Baurain, Hanikenne, & Motte, 2012). Four other candidate genes encoding F‐box proteins , Auxin response factor 22, Pyrophosphate‐energized vacuolar membrane proton pump (EC 3.6.1.1) , and Ferritin 2 proteins were reported to mediate auxin action in biotic and abiotic stress responses, regulation of salt and drought stress tolerance and protection against oxidative stress (An et al., 2019; Bouzroud et al., 2018; Briat et al., 2010; Fukuda, Chiba, Maeda, Nakamura, & Maeshima, 2004).…”

F-Box Genes in the Wheat Genome and Expression Profiling in Wheat at Different Developmental Stages

“…F-box proteins play regulatory roles in protein degradation through the proteolytic mechanism of multi-protein E3 ubiquitin ligase in response to cellular signals during plant development and growth, hormone responses, and biotic/abiotic stress responses [ 2 ]. For example, in wheat, the TaFBA1 F-box protein with a FBA domain has been implicated in drought tolerance [ 37 ], whereas the F-box protein TaJAZ1 regulates resistance against powdery mildew [ 38 ], and the cyclin F-box domain TaCFBD gene is involved in inflorescence development and cold stress responses [ 39 ]. To date, however, a functional analysis of wheat F-box genes was conducted at the single gene level despite the important roles in several aspects of plant abiotic/biotic stress and development.…”

Identification of Candidate Genes for Root Traits Using Genotype–Phenotype Association Analysis of Near-Isogenic Lines in Hexaploid Wheat (Triticum aestivum L.)

“…An F-box gene, TaFBA1 , was identified in wheat organs, including roots [ 57 ]. In other few studies, overexpression of the gene showed drought tolerance, oxidative stress tolerance, heat tolerance, and longer root lengths relative to wild-genotype transgenic tobacco and Arabidopsis [ 56 , 57 , 58 , 59 ]. In rice, overexpression of MAIF1 improved abiotic stress tolerance and helped to control root growth through multiple signal pathways, including negative signaling with abscisic acid (ABA), auxin, and ABA interactions, and the sucrose signaling pathway [ 62 ].…”