Abstract
Adverse environmental conditions such as high temperature and drought stress greatly limit the growth and production of crops worldwide. Several NAC (NAM, ATAF1/2, and CUC2) proteins have been documented as important regulators in stress responses, but the molecular mechanisms are largely unknown. Here, a stress-responsive NAC gene, SNAC3 (ONAC003, LOC_Os01g09550), conferring drought and heat tolerance in rice is reported. SNAC3 was ubiquitously expressed and its transcript level was induced by drought, high temperature, salinity stress, and abscisic acid (ABA) treatment. Overexpression (OE) of SNAC3 in rice resulted in enhanced tolerance to high temperature, drought, and oxidative stress caused by methyl viologen (MV), whereas suppression of SNAC3 by RNAi resulted in increased sensitivity to these stresses. The SNAC3-OE transgenic plants exhibited significantly lower levels of H2O2, malondiadehyde (MDA), and relative electrolyte leakage than the wild-type control under heat stress conditions, implying that SNAC3 may confer stress tolerance by modulating reactive oxygen species (ROS) homeostasis. Quantitative PCR experiments showed that the expression of a large number of ROS-scavenging genes was dramatically increased in the SNAC3-OE plants, but significantly decreased in the SNAC3-RNAi transgenic plants. Five ROS-associated genes which were up-regulated in SNAC3-OE plants showed co-expression patterns with SNAC3, and three of the co-expressed ROS-associated enzyme genes were verified to be direct target genes of SNAC3. These results suggest that SNAC3 plays important roles in stress responses, and it is likely to be useful for engineering crops with improved tolerance to heat and drought stress.
Highlights
Plants frequently encounter diverse environmental cues which restrict their growth and development
Overexpression (OE) of SNAC3 in rice resulted in enhanced tolerance to high temperature, drought, and oxidative stress caused by methyl viologen (MV), whereas suppression of SNAC3 by RNAi resulted in increased sensitivity to these stresses
In the systematic analysis of the NAC family in rice, a significant portion of the family genes were found to be responsive to various abiotic stresses (Fang et al, 2008), and one of them, designated as SNAC3 or ONAC003 (LOC_Os01g09550), which belongs to subfamily II, including the closest Arabidopsis homologue At4g29230 with unknown function, was subjected to further functional characterization in this study
Summary
Plants frequently encounter diverse environmental cues which restrict their growth and development. Among the adverse external stimuli, extreme temperature and water deficit are two major factors that plants frequently confront. To compensate for their sessile lifestyle, plants have evolved a series of sophisticated but efficient strategies to cope with stress conditions. Among these strategies, plants respond to the stresses through stress-specific signalling pathways, which. Plants perceive the external signals through sensors, and trigger changes in expression of numerous stressresponsive genes and the synthesis of diverse functional proteins to enable them to survive. Various transcription factors function as central regulators and molecular switches for gene expression control in the stress signalling and adaptation networks (Zhang et al, 2011)
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.
