Overexpression ofPYL5in rice enhances drought tolerance, inhibits growth, and modulates gene expression

Abstract

Abscisic acid (ABA) is a phytohormone that plays important roles in the regulation of seed dormancy and adaptation to abiotic stresses. Previous work identified OsPYL/RCARs as functional ABA receptors regulating ABA-dependent gene expression in Oryza sativa. OsPYL/RCARs thus are considered to be good candidate genes for improvement of abiotic stress tolerance in crops. This work demonstrates that the cytosolic ABA receptor OsPYL/RCAR5 in O. sativa functions as a positive regulator of abiotic stress-responsive gene expression. The constitutive expression of OsPYL/RCAR5 in rice driven by the Zea mays ubiquitin promoter induced the expression of many stress-responsive genes even under normal growth conditions and resulted in improved drought and salt stress tolerance in rice. However, it slightly reduced plant height under paddy field conditions and severely reduced total seed yield. This suggests that, although exogenous expression of OsPYL/RCAR5 is able to improve abiotic stress tolerance in rice, fine regulation of its expression will be required to avoid deleterious effects on agricultural traits.

Evaluating the involvement and interaction of abscisic acid and miRNA156 in the induction of anthocyanin biosynthesis in drought-stressed plants

“…However, the (Risk et al 2009;Taiz and Zeiger 2010;Miyakawa et al 2013). By contrast, the action of PYR/RCAR as an ABA receptor is well supported by several studies (Kharenko et al 2013;Gonzalez-Guzman et al 2014;Kim et al 2014). Furthermore, a critical review of the current status of our understanding of ABA receptors supports the idea that only the PYR/RCAR can currently be referred to as a bona fide ABA receptor.…”

The impact of over-expression of NPK1 gene on growth and yield of sorghum under drought stress

“…Drought tolerance assay was applied as described in Kim et al (2014) with modifications. Briefly, T1 seeds from each transgenic line and non-transgenic lines were surface-sterilized and germinated for four days in the dark at 25°C on half-strength MS basal medium containing 1% sucrose with or without 5 mg/L bialaphos for transgenic and non-transgenic plants, respectively.…”

Fundamental and applied research in ABA signaling: Regulation by ABA of the chromatin remodeling ATPase BRAHMA and biotechnological use of the PP2CA promoter.

“…The acquired knowledge about the ABA inducibility of the PP2CA promoter prompted us to exploit this as a biotechnological tool. The use of ABA inducible promoters could potentially avoid the growth penalty observed in transgenic lines with a constitutive overexpression of ABA signaling core components observed before (Santiago et al, 2009b, Kim et al, 2014. Our results suggested this is a good strategy to direct the expression of ABA receptors only under stress conditions in order to enhance drought resistance in commercial crops.…”

“…Overexpression of monomeric ABA receptors confers drought tolerance (Santiago et al, 2009b, Gonzalez-Guzman et al, 2014, Yan & Chen, 2016, Yang et al, 2016b, but a penalty on growth under normal conditions has been described in some cases (Kim et al, 2014). Expression driven by an ABA-inducible promoter might solve this problem.…”

“…Reduced water availability, will induce ABA accumulation, which will activate PP2CA promoter leading to increased PYR/PYL expression. This could help the plant to tolerate the stress since plants overexpressing PYR/PYL receptors are drought tolerant (Santiago et al, 2009b, Kim et al, 2014, Yang et al, 2016a …”