Abstract
The nucleotide-binding domain leucine-rich repeat (NLR) immune receptors play important roles in innate plant immunity. The activation of NLRs is specifically induced by their cognate effectors released from pathogens. Autoactive NLRs are expected to confer broad-spectrum resistance because they do not need cognate effectors to activate their immune responses. In this study, we demonstrated that the NLR genes RPS2 and RPM1(D505V) from Arabidopsis were autoactive in Oryza sativa and conferred broad-spectrum resistance to fungal pathogen Magnaporthe oryzae, bacterial pathogen Xanthomonas oryzae pv. oryzae (Xoo), and pest brown planthopper (BPH, Nilaparvata lugens Stål). These results revealed that interfamily transfer of dicot NLRs to monocot species could be functional. The transgenic plants displayed early and strong induction of reactive oxygen species (ROS), callose deposition, and expression of defense-related genes after challenged with M. oryzae. The transcriptome analysis showed that the expressions of some defense-related genes were primed to adapt the transformed autoactive NLRs in the transgenic plants. This study indicates that autoactive NLRs are a promising resource for breeding crops with broad-spectrum resistance and provides new insights for engineering disease resistance.
Highlights
Plants are constantly threatened by a wide range of pathogens in nature, and plants have evolved a complicated and multifaceted innate immune system to combat pathogen attacks
Since the autoactive nucleotide-binding domain leucine-rich repeat (NLR) usually result in broad-spectrum disease resistance, AtRPS2 and AtRPM1(D505V) transgenic rice plants under the control of ZmUbi promoter were generated to determine the function of AtRPS2 and AtRPM1(D505V) in rice
The significant high lethal ratio and the dwarf growth of the transgenic plants indicate the autoactivation of AtRPS2 and AtRPM1(D505V) in rice
Summary
Plants are constantly threatened by a wide range of pathogens in nature, and plants have evolved a complicated and multifaceted innate immune system to combat pathogen attacks. PTI contributes a basal immunity during pathogen infection (Jones and Dangl, 2006; Couto and Zipfel, 2016; RPS2 and RPM1(D505V) Confer Broad-Spectrum Resistance. RIN4 is guarded by NLR proteins RPM1 and RPS2 in Arabidopsis and is targeted by effectors AvrRpm, AvrB, and AvrRpt. Transfer of NLR genes such as RPS2 to the plant species without their suppressive genes such as RIN4 can obtain autoactive NLRs. NLRs have conserved domains to regulate the switch between inactive and active states. The results suggest that NLRs share conserved signal pathways among different species, and it is possible that NLR proteins from Arabidopsis can be used in rice to confer resistance. The results showed that these transgenic rice plants increased resistance against fungal pathogen M. oryzae, bacterial pathogen Xoo and insect pest BPH. Our observations revealed that interfamily transfer NLR genes will broaden the resources for breeding multi-resistance crops
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
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 call
