An abscisic acid (ABA) homeostasis regulated by its production, catabolism and transport in peanut leaves in response to drought stress

Abstract

ABA is an important messenger that acts as a signaling mediator for regulating the adaptive response of plants to drought stress. Two production pathways, de novo biosynthesis and hydrolysis of glucose-conjugated ABA by β-glucosidase (BG), increase cellular ABA levels in plants. ABA catabolism via hydroxylation by 8’-hydroxylase (CYP707A), or conjugation by uridine diphosphate glucosyltransferase (UGT), decreases cellular ABA levels. The transport of ABA through ATP-binding cassette (ABC)-containing transporter proteins, members of ABC transporter G family (ABCG), across plasma membrane (PM) is another important pathway to regulate cellular ABA levels. In this study, based on our previously constructed transcriptome of peanut leaves in response to drought stress, fourteen candidate genes involved in ABA production (including AhZEP , AhNCED1 and AhNCED3 , AhABA2 , AhAAO1 and AhAAO2 , AhABA3 , AhBG11 and AhBG24 ), catabolism (including AhCYP707A3 , AhUGT71K1 and AhUGT73B4 ) and transport (including AhABCG22-1 and AhABCG22-2 ), were identified homologously and phylogenetically, and further analyzed at the transcriptional level by real-time RT-PCR, simultaneously determining ABA levels in peanut leaves in response to drought. The high sequence identity and very similar subcellular localization of the proteins deduced from 14 identified genes involved in ABA production, catabolism and transport with the reported corresponding enzymes in databases suggest their similar roles in regulating cellular ABA levels. The expression analysis showed that the transcripts of AhZEP , AhNCED1 , AhAAO2 and AhABA3 instead of AhABA2 , AhNCED3 and AhAAO1 in peanut leaves increased significantly in response to drought stress; and that the AhBG11 and AhBG24 mRNA levels were rapidly and significantly up-regulated, with a 4.83- and 4.58-fold increase, respectively at 2-h of drought stress. The genes involved in ABA catabolism AhCYP707A3 , AhUGT71K1 instead of AhUGT73B4 were significantly induced in response to drought stress. The expression of two closely related peanut ABCG genes, AhABCG22 . 1 and AhABCG22 . 2 , was significantly up-regulated in response to drought stress. The ABA levels rapidly began to accumulate within 2 h (a 56.6-fold increase) from the start of drought stress, and peaked at 10 h of the stre...

Overexpression of the HDA15 Gene Confers Resistance to Salt Stress by the Induction of NCED3, an ABA Biosynthesis Enzyme

“…NCED genes catalyze the synthesis of xanthoxin, which is converted to abscisic aldehyde by short-chain alcohol dehydrogenase/reductase (SDR/ABA2) and then to ABA by abscisic aldehyde oxidase (AAO3). The molybdenum cofactor sulfurase/ABA3 is required by aldehyde oxidase for its activity (Long et al, 2019). However, as ABA2, ABA3, and AAO3 play only minor roles in ABA biosynthetic pathway (Ma et al, 2018), their transcript levels were not significantly increased in HDA15 OE plants (Figure 8).…”

“…However, as ABA2, ABA3, and AAO3 play only minor roles in ABA biosynthetic pathway (Ma et al, 2018), their transcript levels were not significantly increased in HDA15 OE plants (Figure 8). In addition, the higher accumulation of ABA in HDA15 OE plants may be due to BG2 upregulation, which catalyzes inactive ABA-GE to ABA in one-step hydrolysis (Long et al, 2019). Induction of BG2 also helps plants to quickly enhance internal ABA levels for stress adaptation.…”

Genome-Wide Identification and Characterization of Long Non-Coding RNAs in Peanut

“…Target gene LOC112730895 of hub lncRNA MSTRG.41333.1 encodes ABC transporter C family member 15 (Figure 6a). It was reported that ABA homeostasis contributes to drought tolerance through a balance between the production, catabolism and transport in peanut leaves [45]. Target gene LOC112726802 of hub lncRNA MSTRG.47603.1 encodes BON1-associated protein 2, which is a plasma membrane-localized protein, plays a negative role in regulating the expression of immune receptor genes, but has a positive regulation in stomatal closure [46].…”

Leaf Soluble Sugars and Free Amino Acids as Important Components of Abscisic Acid—Mediated Drought Response in Tomato

“…As a stress hormone, abscisic acid (ABA) is involved in the response to various adverse environmental factors, particularly to drought, through the regulation of specific signalling pathways and the modification of gene expression levels [ 7 , 8 , 9 , 10 , 11 ]. Under drought, ABA controls water loss through stomata closure, transpiration flux reduction, a decrease in water potential (ψ), and a reduction in leaf area [ 12 ].…”