Cinnamoyl coA: NADP oxidoreductase-like 1 regulates abscisic acid response by modulating phaseic acid homeostasis in Arabidopsis thaliana

Abstract

Phaseic acid (PA), a main catabolite of abscisic acid (ABA), is structurally related to ABA and possesses ABA-like hormonal activity. However, the comprehensive metabolism pathway and roles of PA is not well understood. Here, we identified the previously named CRL1 (Cinnamoyl coA:NADP oxidoreductase like 1) as a PA reductase that catalyzes PA to dihydrophaseic acid (DPA) via a homologous alignment and expression pattern analysis strategy in Arabidopsis. The function of CRL1 and the potential role of PA were studied in the genetically transgenic material of CRL1. Overexpression of CRL1 (OE) resulted in decreased ABA sensitivity in seed germination and attenuated drought tolerance. In contrast, increased ABA sensitivity and elevated drought tolerance was observed in down-regulated and loss-of-function crl1 mutants. The Tyr162 residues in the conserved motif of CRL1 is key to the PA catalytic activity. Accelerated seed germination and earlier flowering phenotype was also observed in OE lines, while retarded seed germination and delayed flowering time in crl1 mutants which accumulated more PA while less DPA than the wildtype (WT). This study demonstrates that PA plays diverse functions in plant including drought tolerance, seed germination and flowering in an ABA-like manner, which may expand the plant adaptive plasticity.

Neophaseic acid catabolism in the 9′-hydroxylation pathway of abscisic acid in Arabidopsis thaliana

“…The 8′-hydroxylation pathway is the main route of ABA hydroxylation, in which catabolite structures, related enzymes, and biological functions have been extensively studied ( Kushiro et al., 2004 ; Mizutani and Todoroki, 2006 ; Nambara and Marionpoll, 2005 ; Weng et al., 2016 ; Yin et al., 2022 ). In this pathway, ABA is initially catalyzed by 8′-hydroxylase and converted into the unstable intermediate 8′-hydroxy ABA (8′-OH ABA) ( Milborrow, 1969 ) ( Figure 1 ).…”

“…CYP707A genes play a key role in seed development and germination through the hydroxylation of ABA ( Kushiro et al., 2004 ). Recently, the two PARs ABH2 (ABA hypersensitive 2) and CRL1 (cinnamoyl coA:NADP oxidoreductase like 1) from the NAD(P)-binding Rossmann-fold protein superfamily were identified and confirmed to participate in seed germination and drought tolerance in Arabidopsis ( Weng et al., 2016 ; Yin et al., 2022 ).…”

A Genome-Wide Association Study Coupled With a Transcriptomic Analysis Reveals the Genetic Loci and Candidate Genes Governing the Flowering Time in Alfalfa (Medicago sativa L.)

“…Phaseic acid (PA), the main catabolite of ABA, is structurally related to ABA and exhibits ABA-like hormone activity ( Nambara and Marion-Poll, 2005 ). In A. thaliana plants overexpressing Cinnamoyl-coA: NADP oxidoreductase-like 1 (CRL1), which encodes a PA reductase that catalyses the formation of dihydrophaseic acid from PA, both the seed germination rate and flowering time were increased ( Yin et al, 2022 ). Msa0344630 also encodes cinnamoyl-coA, and its expression was significantly increased according to the RNA-seq data.…”

The phytomelatonin receptor PMTR1 regulates seed development and germination by modulating abscisic acid homeostasis in Arabidopsis thaliana

“…After 2 days of stratification at 4°C in the dark, the seeds were transferred to a growth chamber with a 16‐h light/8‐h dark photoperiod, at 23°C. Seeds with an emerging radicle were considered to be germinated seeds 41 …”

“…The extraction and determination of ABA, phaseic acid (PA), and dihydrophaseic acid (DPA) were performed by following the protocol described in our previous reports. 41,44 Briefly, [ 2 H 6 ] ABA (Olomouc), [ 2 H 3 ] PA (National Research Council Plant Biotechnology Institute), and [ 2 H 3 ] DPA (National Research Council Plant Biotechnology Institute) were used as internal standards. Plant tissues of 50 mg were frozen in liquid nitrogen and ground into fine powder.…”