A novel membrane‐bound E3 ubiquitin ligase enhances the thermal resistance in plants

Abstract

SummaryHigh temperature stress disturbs cellular homoeostasis and results in a severe retardation in crop growth and development. Thus, it is important to reveal the mechanism of plants coping with heat stress. In this study, a novel gene that we identified from Brassica napus, referred to as BnTR1, was found to play a key role in heat stress response in planta. BnTR1 is a membranebound RINGv (C 4 HC 3 ) protein that displays E3 ligase activity in vitro. We demonstrated that modest expression of BnTR1 is sufficient to minimize adverse environmental influence and confers thermal resistance on development without any detrimental effects in B. napus and Oryza sativa. Our investigation into the action mechanism indicates that BnTR1 is likely to be involved in mediating Ca 2+ dynamics by regulating the activity of calcium channels, which further alters the transcripts of heat shock factors and heat shock proteins contributing to plant thermotolerance. Hence, our study identified BnTR1 as a novel key factor underlying a conserved mechanism conferring thermal resistance in plants.

The RING Finger Ubiquitin E3 Ligase OsHTAS Enhances Heat Tolerance by Promoting H2O2-Induced Stomatal Closure in Rice

“…The rice RING finger E3 ligase HEAT AND COLD INDUCED1 drives the nuclear export of multiple substrate proteins, and its heterogenous overexpression enhances acquired thermotolerance (Lim et al, 2013a). A novel membranebound RING-V (C4HC3) protein from Brassica napus, BnTR1, is likely to be involved in mediating Ca 2+ dynamics by regulating the activity of calcium channels, which further alters the transcription of heat shock factors and heat shock proteins contributing to plant thermotolerance (Liu et al, 2014).…”

Natural variation in PTB1 regulates rice seed setting rate by controlling pollen tube growth

“…We cloned and expressed the intact RING functional region of PTB1 in Escherichia coli and then used the GST-tagged GST-RING to verify its activity in vitro using Brassica BnTR1 (ref. 36) as a positive control. In the presence of ubiquitin, E1 and E2 (UbcH5b), BnTR1 or GST-RING could carry out selfubiquitination, whereas in the absence of any of the E1, E2 or E3 enzymes, no clear protein ubiquitination was detected (Fig.…”

“…The fusion protein was then prepared for ubiquitination analysis according to the manufacturer's protocol. Assays for in vitro ubiquitination were carried out according to the protocols of Song et al 4 and Liu et al 36 Brassica napus E3 ubiquitin ligase BnTR1 (ref. 36) was used as a positive control, and GST was used as a negative control.…”

“…Assays for in vitro ubiquitination were carried out according to the protocols of Song et al 4 and Liu et al 36 Brassica napus E3 ubiquitin ligase BnTR1 (ref. 36) was used as a positive control, and GST was used as a negative control. Ubiquitinated proteins were detected by protein blot analysis using an ubiquitin antibody (Cell Signaling Technology, 1/1,000(v/v)).…”

Ubiquitination pathway as a target to develop abiotic stress tolerance in rice

“…BnTR1 acts in the regulation of Ca 2C channels, activating transcription factors and heat shock proteins that contribute to plant thermal tolerance. 39 Another study revealed that OsHCI1 (Heat and Cold Induced 1) gene, which presents E3-ubiquitin ligase activity and is mainly associated to the Golgi apparatus, interacts with several proteins, mediating their transportation from the nucleus to the cytoplasm through mono-ubiquitination.…”