Abstract
With global climate change, plants are frequently being exposed to various stresses, such as pathogen attack, drought, and extreme temperatures. Transcription factors (TFs) play crucial roles in numerous plant biological processes; however, the functions of many tomato (Solanum lycopersicum L.) TFs that regulate plant responses to multiple stresses are largely unknown. Here, using an RNA-seq approach, we identified SlNAP1, a NAC TF-encoding gene, which was strongly induced by various stresses. By generating SlNAP1 transgenic lines and evaluating their responses to biotic and abiotic stresses in tomato, we found that SlNAP1-overexpressing plants showed significantly enhanced defense against two widespread bacterial diseases, leaf speck disease, caused by Pseudomonas syringae pv. tomato (Pst) DC3000, and root-borne bacterial wilt disease, caused by Ralstonia solanacearum. In addition, SlNAP1 overexpression dramatically improved drought tolerance in tomato. Although the SlNAP1-overexpressing plants were shorter than the wild-type plants during the early vegetative stage, eventually, their fruit yield increased by 10.7%. Analysis of different hormone contents revealed a reduced level of physiologically active gibberellins (GAs) and an increased level of salicylic acid (SA) and abscisic acid (ABA) in the SlNAP1-overexpressing plants. Moreover, EMSAs and ChIP-qPCR assays showed that SlNAP1 directly activated the transcription of multiple genes involved in GA deactivation and both SA and ABA biosynthesis. Our findings reveal that SlNAP1 is a positive regulator of the tomato defense response against multiple stresses and thus may be a potential breeding target for improving crop yield and stress resistance.
Highlights
IntroductionVarious stresses, such as pathogen attack, drought, and extreme temperatures, are occurring more frequently across the world
With global climate change, various stresses, such as pathogen attack, drought, and extreme temperatures, are occurring more frequently across the world
We found that SlNAP1-GFP localized to the plasma membrane and nucleus (Fig. 1c)
Summary
Various stresses, such as pathogen attack, drought, and extreme temperatures, are occurring more frequently across the world. Tomato (Pst) DC3000, Botrytis cinerea (B. cinerea) and Alternaria brassicicola in Arabidopsis[12,13], while the ATAF1 homolog in rice, OsNAC6, plays a positive role in plant defense, as transgenic plants overexpressing OsNAC6 show enhanced resistance to Magnaporthe grisea[14]. Two closely related NAC TFs in tomato, jasmonic acid 2 (JA2) and JA2-like (JA2L), play opposite roles in immunity against Pst DC3000 by differentially regulating stomatal closure and reopening[15]. Solanum lycopersicum stress-related NAC1 (SlSRN1) functions positively in the defense against Pst DC3000 and B. cinerea, while SlSRN1 acts as a negative regulator of drought tolerance in tomato[16]. The functions of NAC proteins in response to different stresses are complex and still obscure
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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.
