OsJAZ1 Attenuates Drought Resistance by Regulating JA and ABA Signaling in Rice

Abstract

Jasmonates (JAs) and abscisic acid (ABA) are phytohormones known play important roles in plant response and adaptation to various abiotic stresses including salinity, drought, wounding, and cold. JAZ (JASMONATE ZIM-domain) proteins have been reported to play negative roles in JA signaling. However, direct evidence is still lacking that JAZ proteins regulate drought resistance. In this study, OsJAZ1 was investigated for its role in drought resistance in rice. Expression of OsJAZ1 was strongly responsive to JA treatment, and it was slightly responsive to ABA, salicylic acid, and abiotic stresses including drought, salinity, and cold. The OsJAZ1-overexpression rice plants were more sensitive to drought stress treatment than the wild-type (WT) rice Zhonghua 11 (ZH11) at both the seedling and reproductive stages, while the jaz1 T-DNA insertion mutant plants showed increased drought tolerance compared to the WT plants. The OsJAZ1-overexpression plants were hyposensitive to MeJA and ABA, whereas the jaz1 mutant plants were hypersensitive to MeJA and ABA. In addition, there were significant differences in shoot and root length between the OsJAZ1 transgenic and WT plants under the MeJA and ABA treatments. A subcellular localization assay indicated that OsJAZ1 was localized in both the nucleus and cytoplasm. Transcriptome profiling analysis by RNA-seq revealed that the expression levels of many genes in the ABA and JA signaling pathways exhibited significant differences between the OsJAZ1-overexpression plants and WT ZH11 under drought stress treatment. Quantitative real-time PCR confirmed the expression profiles of some of the differentially expressed genes, including OsNCED4, OsLEA3, RAB21, OsbHLH006, OsbHLH148, OsDREB1A, OsDREB1B, SNAC1, and OsCCD1. These results together suggest that OsJAZ1 plays a role in regulating the drought resistance of rice partially via the ABA and JA pathways.

Functions of Jasmonic Acid in Plant Regulation and Response to Abiotic Stress

“…Jasmonate ZIM-domain proteins (JAZ) are regulators, typically repressors, in the JA signaling pathway. Fu et al [33] demonstrated that OsJAZ1 plays a negative regulatory role in rice drought stress tolerance, particularly in relation to the ABA and JA signaling pathways. In addition, Seo et al [18] found that OsbHLH148, a basic helix-loop-helix protein, acts as a transcriptional regulator and up regulates OsDREB1 and OsJAZ, which are involved in drought stress responses and the JA signaling pathway, respectively.…”

Jasmonic Acid Signaling Pathway in Response to Abiotic Stresses in Plants

“…The increase in the endogenous JA content was rapid and transient in A. thaliana [21] and citrus (Citrus paradisi × Poncirus trifoliata) [115] immediately after drought stress, but the content decreased to the basal level with prolongation of the stress. MeJA treatment could improve the drought resistance in peanut (Arachis hypogaea) [116], rice (Oryza sativa) [117], soybean (Glycine max) [118], and broccoli (Brassica oleracea) plants [119]. The application of exogenous MeJA not only increased the total carbohydrate, polysaccharide, total soluble sugar, free amino acid, total proline, and protein contents, but also the activities of catalase (CAT), POD, and SOD in maize plants (Zea mays) [120].…”

A point‐to‐point protein–protein interaction assay reveals the signaling interplays among plant hormones and environmental cues

“…The result is consistent with the data showing that JAZ1 is involved in the crosstalk between the JA and ABA signaling pathways though JAZ1-PYL interactions. The expression of OsJAZ1 not only responds to JA but also induced by ABA (Fu et al, 2017). The different ABA responses of JAZ1 and OsJAZ1 may be derived from their species.…”

“…A reasonable hypothesis is that ABA and JA co-regulate plant growth and development and that JAZ1 is involved in this process. In addition, these interactions may explain the JA-hypersensitive phenotype of pyl4 mutant and the ABA-hypersensitive phenotype of osjaz1 mutant (Fu et al, 2017;Lackman et al, 2011).…”

“…JAZ12 stability is modulated by the E3 ubiquitin ligase KEG (Pauwels et al, 2015). In addition, OsJAZ1, whose mutant plants are hypersensitive to MeJA and ABA, plays a role in the drought resistance of rice partially via the ABA and JA signaling pathways (Fu et al, 2017). The pyl4 mutant plants are hypersensitive to a JA treatment, and the expression levels of this subgroup of ABA receptors change upon JA treatment (Lackman et al, 2011).…”