The Arabidopsis thaliana E3 Ubiquitin Ligase BRIZ Functions in Abscisic Acid Response

Abstract

The ubiquitin system is essential for multiple hormone signaling pathways in plants. Here, we show that the Arabidopsis thaliana E3 ligase BRIZ, a heteromeric ligase that consists minimally of BRIZ1 and BRIZ2 proteins, functions in abscisic acid (ABA) signaling or response. briz1 and briz2 homozygous mutants either fail to germinate or emerge later than wild-type seedlings, with little cotyledon expansion or root elongation and no visible greening. Viability staining indicates that briz1 and briz2 embryos are alive but growth-arrested. Germination of briz mutants is improved by addition of the carotenoid biosynthetic inhibitor fluridone or gibberellic acid (GA3), and briz mutants have improved development in backgrounds deficient in ABA synthesis (gin1-3/aba2) or signaling (abi5-7). Endogenous ABA is not higher in briz2 seeds compared to wild-type seeds, and exogenous ABA does not affect BRIZ mRNAs in imbibed seeds. These results indicate that briz embryos are hypersensitive to ABA and that under normal growth conditions, BRIZ acts to suppress ABA signaling or response. ABA signaling and sugar signaling are linked, and we found that briz1 and briz2 mutants excised from seed coats are hypersensitive to sucrose. Although briz single mutants do not grow to maturity, we were able to generate mature briz2-3 abi5-7 double mutant plants that produced seeds. These seeds are more sensitive to exogenous sugar and are larger than seeds from sibling abi5-7 BRIZ2/briz2-3 plants, suggesting that BRIZ has a parental effect on seed development. From these data, we propose a model in which the BRIZ E3 ligase suppresses ABA responses during seed maturation and germination and early seedling establishment.

Global ubiquitinome analysis reveals the role of E3 ubiquitin ligase FaBRIZ in strawberry fruit ripening

“…Our study not only represents a strategy for discovering new E3 ligases in certain biological processes, but also provides insights into the role of E3 ligases in controlling strawberry fruit ripening. Recently, it was reported that the homolog of FaBRIZ in Arabidopsis, AtBRIZ2, was capable of combining with AtBRIZ1, a close ortholog of AtBRIZ2, to form a functional ubiquitin E3 ligase complex, and regulate seed germination and seeding growth ( Hsia and Callis, 2010 ; Linden et al , 2021 ). This modulation might be achieved through the regulation of ABA signalling and response by these two BRIZ proteins ( Linden et al , 2021 ).…”

“…Recently, it was reported that the homolog of FaBRIZ in Arabidopsis, AtBRIZ2, was capable of combining with AtBRIZ1, a close ortholog of AtBRIZ2, to form a functional ubiquitin E3 ligase complex, and regulate seed germination and seeding growth ( Hsia and Callis, 2010 ; Linden et al , 2021 ). This modulation might be achieved through the regulation of ABA signalling and response by these two BRIZ proteins ( Linden et al , 2021 ). Considering that ABA plays a key role in the regulation of strawberry fruit ripening ( Jia et al , 2011 ), it is conceivable that FaBRIZ might regulate fruit ripening through directly or indirectly affecting the ABA pathway, although the direct targets of FaBRIZ remain to be determined.…”

Expression Profiling of Salt-Responsive Genes and Transcription Factors in Leaf Transcriptome of Arabidopsis thaliana

“…Zinc finger (ZF) proteins, with their characteristic finger-like structure [57], are ubiquitously distributed in eukaryotes and encompass several RING zinc finger proteins within Arabidopsis thaliana [58]. These ZF proteins play an instrumental role in signaling cascades and plant adaptation to adverse environmental conditions, including drought, temperature, and salinity [59].…”

RING Zinc Finger Proteins in Plant Abiotic Stress Tolerance

“…Zinc finger proteins maintain a finger-like spatial configuration by binding to zinc ions through amino acids in the peptide chain, and are widely distributed in eukaryotes ( Han et al, 2020a ). RING zinc finger proteins have been identified in many plants, including Arabidopsis thaliana ( Linden et al, 2021 ; Liu et al, 2021 ; Van Nguyen et al, 2021 ), rice ( Oryza sativa ) ( Kim et al, 2020 ; Kim and Jang, 2021 ; Zhu et al, 2021 ), maize ( Zea mays ) ( Gao et al, 2012 ; Xia et al, 2012 ; Yang et al, 2018 ), pepper ( Capsicum annuum ) ( Liu et al, 2007 ; Joo et al, 2019a , 2020 ), wheat ( Triticum aestivum ) ( Agarwal and Khurana, 2018 ; Liu et al, 2018 ; Wang et al, 2020 ), potato ( Solanum tuberosum ) ( Guo et al, 2003 ; Ni et al, 2010 ; Qi et al, 2020 ), wild tomato ( Solanum pimpinellifolium ) ( Yang et al, 2016 ), wild Chinese grape ( Vitis pseudoreticulata ) ( Yu et al, 2013 ; Wang et al, 2017 ), soybean ( Glycine max ) ( Du et al, 2010 ; Biniek et al, 2017 ; Zhao et al, 2020 ), Brassica rapa ( Jung et al, 2013 ), tobacco ( Nicotiana benthamiana) ( Wu et al, 2014 ), and cassava ( Manihot esculenta Crantz) ( Dos Reis et al, 2012 ). RING zinc finger proteins have a characteristic RING zinc finger domain.…”