Abstract
BackgroundThe NAC (NAM, AFAT, and CUC) transcription factors play critical roles in rice (Oryza sativa) development and stress regulation. Overexpressing a microRNA (miR164b)-resistant OsNAC2 mutant gene, which generates transcripts that cannot be targeted by miR164b, improves rice plant architecture and yield; however, the performance of these mOsNAC2-overexpressing lines, named ZUOErN3 and ZUOErN4, under abiotic stress conditions such as drought have not yet been fully characterized.ResultsIn this study, we showed that the germination of ZUOErN3 and ZUOErN4 seeds was delayed in comparison with the wild-type (WT) seeds, although the final germination rates of all lines were over 95%. The quantification of the endogenous ABA levels revealed that the germinating mOsNAC2-overexpressing seeds had elevated ABA levels, which resulted in their slower germination. The mOsNAC2-overexpressing plants were significantly more drought tolerance than the WT plants, with the survival rate increasing from 11.2% in the WT to nearly 70% in ZUOErN3 and ZUOErN4 plants after a drought treatment. Salt (NaCl) tolerance was also increased in the ZUOErN3 and ZUOErN4 plants due to significantly increased ABA levels. A reverse transcription quantitative PCR (RT-qPCR) analysis showed a significant increase in the expression of the ABA biosynthesis genes OsNCED1 and OsNCED3 in the mOsNAC2-overexpressing lines, and the expression levels of the stress-responsive genes OsP5CS1, OsLEA3, and OsRab16 were significantly increased in these plants. Moreover, OsNAC2 directly interacted with the promoters of OsLEA3 and OsNCED3 in yeast one-hybrid assays.ConclusionsTaken together, our results show that OsNAC2 plays a positive regulatory role in drought and salt tolerance in rice through ABA-mediated pathways.
Highlights
The NAC (NAM, AFAT, and CUC) transcription factors play critical roles in rice (Oryza sativa) development and stress regulation
abscisic acid (ABA) biosynthesis and the resulting endogenous ABA levels are increased under abiotic stresses, with drought and salt stresses representing the most important environmental signals upregulating the transcription of the ABA biosynthesis genes (Xiong et al, 2003)
The overexpression of OsNAC2 slows down germination In our previous study, we showed the miR164b-resistant mOsNAC2-overexpressing lines, ZUOErN3 and ZUOErN4, had a significant high-yield potential (Jiang et al, 2018)
Summary
The NAC (NAM, AFAT, and CUC) transcription factors play critical roles in rice (Oryza sativa) development and stress regulation. Rice (Oryza sativa L.) is a major food crop worldwide, and as the population increases, so does the demand for this crop; rice is often exposed to drought, salt, and other stresses, which may severely affect its yield (Valliyodan and Nguyen, 2006). ABA biosynthesis and the resulting endogenous ABA levels are increased under abiotic stresses, with drought and salt stresses representing the most important environmental signals upregulating the transcription of the ABA biosynthesis genes (Xiong et al, 2003). The NAC (NAM, AFAT, and CUC) family of transcription factors (TFs) are plant-specific, and 151 of them have been detected in rice (Nuruzzaman et al, 2010).
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
