iTRAQ-Based Analysis of Proteins Co-Regulated by Brassinosteroids and Gibberellins in Rice Embryos during Seed Germination

Abstract

Seed germination, a pivotal process in higher plants, is precisely regulated by various external and internal stimuli, including brassinosteroid (BR) and gibberellin (GA) phytohormones. The molecular mechanisms of crosstalk between BRs and GAs in regulating plant growth are well established. However, whether BRs interact with GAs to coordinate seed germination remains unknown, as do their common downstream targets. In the present study, 45 differentially expressed proteins responding to both BR and GA deficiency were identified using isobaric tags for relative and absolute quantification (iTRAQ) proteomic analysis during seed germination. The results indicate that crosstalk between BRs and GAs participates in seed germination, at least in part, by modulating the same set of responsive proteins. Moreover, most targets exhibited concordant changes in response to BR and GA deficiency, and gene ontology (GO) indicated that most possess catalytic activity and are involved in various metabolic processes. Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) analysis was used to construct a regulatory network of downstream proteins mediating BR- and GA-regulated seed germination. The mutation of GRP, one representative target, notably suppressed seed germination. Our findings not only provide critical clues for validating BR–GA crosstalk during rice seed germination, but also help to optimise molecular regulatory networks.

A transcriptional hub integrating gibberellin–brassinosteroid signals to promote seed germination in Arabidopsis

“…BR and GA are principal plant growth regulators that function redundantly to control many important physiological functions, including seed germinations and cell elongation ( Steber and McCourt, 2001 ; Hu and Yu, 2014 ; Li et al , 2018 ; Zhao et al , 2019 ). Physical interactions between BZR1/BES1 and DELLAs mediate the crosstalk between BRs and GAs during cell elongation in Arabidopsis ( Bai et al , 2012b ; Gallego-Bartolome et al ., 2012; Li et al , 2012 ); however, the molecular mechanism underlying GA–BR crosstalk during seed germination is not well studied.…”

“…These observations indicate that BRs play an auxiliary role in the GA-promoted regulation of seed germination and can reverse the inhibitory effect of ABA ( Steber and McCourt, 2001 ). A recent study using iTRAQ (isobaric tag for relative and absolute quantification) proteomic analysis has revealed that GAs and BRs coordinately regulate rice seed germination and embryo development by modulating the expression of several common targets ( Li et al , 2018 ). However, the molecular mechanisms underlying GA- and BR-induced seed germination have not been thoroughly investigated.…”

Co-expression network analysis reveals PbTGA4 and PbAPRR2 as core transcription factors of drought response in an important timber species Phoebe bournei

“…When water is insufficient, water from different tissues of the plant converges toward mature tissues, resulting in a lack of water in young tissues and retarded growth ( Wakamori and Mineno, 2019 ). To reduce water loss under drought stress, plants reduce stomatal opening and transpiration rates, which restrict the entry of carbon dioxide into the leaves and inhibit photosynthesis to impair biomass accumulation ( Zhang et al., 2009 ; Li et al., 2018 ). At the same time, the reduced transpiration rate also leads to the obstruction of mineral transport in plants, which further aggravates physiological and metabolic disorders in plant cells, leading to the destruction of the cell membrane structure and impaired cell growth ( Lu et al., 2018 ; Lin et al., 2022 ).…”

Comparative Physiological and Proteomic Analyses Reveal the Mechanisms of Brassinolide-Mediated Tolerance to Calcium Nitrate Stress in Tomato

“…Importantly, exogenous BR influences protein biosynthesis as well as the degradation of damaged proteins. For instance, BR alters the accumulation of heat shock proteins, proteases, and antioxidant enzymes in plants ( Li et al, 2013 ; An et al, 2016 ; Li et al, 2018 ). However, the effect of BR and Ca(NO 3 ) 2 on plant proteome and the potential mechanism of stress mitigation remain elusive.…”