TaRPM1 positively regulates wheat high-temperature seedling-plant resistance to Puccinia striiformis f. sp. tritici

Authors: WANG, JIAHUI - Northwest A&f University; TIAN, WEI - Northwest A&f University; TAO, FEI - Northwest A&f University; WANG, JINGJING - Northwest A&f University; SHANG, HONGSHENG - Northwest A&f University; Chen, Xianming; XU, XIANGMING - East Malling Research; HU, XIAOPING - Northwest A&f University

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/18/2019
Publication Date: 1/15/2020
Citation: Wang, J., Tian, W., Tao, F., Wang, J., Shang, H., Chen, X., Xu, X., Hu, X. 2020. TaRPM1 positively regulates wheat high-temperature seedling-plant resistance to Puccinia striiformis f. sp. tritici. Frontiers in Plant Science. 10(1). https://doi.org/10.3389/fpls.2019.01679.
DOI: https://doi.org/10.3389/fpls.2019.01679

Interpretive Summary: RPM1 is a coiled coil, nuceotide-binding site and leucine-rich repeat (CC-NBS-LRR) domain-containing protein that was first reported to be required for resistance to bacteria in Arabidopsis plants. Our previous study showed that TaRPM1 gene in wheat was up-regulated about six times following infection by the stripe rust pathogen under high temperature, compared with normal temperature. To study the function of TaRPM1 in wheat high-temperature seedling-plant (HTSP) resistance to stripe rust, the full length of TaRPM1 was cloned, with three copies each located on wheat chromosomes 1A, 1B and 1D. Transient expression of the TaRPM1-GFP fusion protein in tobacco indicated that TaRPM1 proteins localize in the cytoplasm and nucleus. The TaRPM1 transcription in wheat leaves was rapidly up-regulated upon inoculation with the stripe rust pathogen under high temperature. In addition, TaRPM1 was induced by exogenous salicylic acid hormone application. Silencing TaRPM1 in wheat cultivar Xiaoyan 6 resulted in reduced HTSP resistance to stripe rust in terms of reduced number of necrotic cells and increased uredinial length, whereas no obvious phenotypic changes were observed in TaRPM1-silenced leaves under normal temperature. Defense related protein genes TaPR1 and TaPR2 were down-regulated in TaRPM1-silenced plants under high temperature. Thus, we conclude that TaRPM1 is involved in HTSP resistance to stripe rust.

Technical Abstract: RPM1 is a CC-NBS-LRR protein that was first shown to be required for resistance to Pseudomonas syringae pv. maculicola in Arabidopsis thaliana. Our previous study showed that TaRPM1 gene in wheat was up-regulated about six times following infection by Puccinia striiformis f. sp. tritici (Pst) under high temperature, compared with normal temperature. To study the function of TaRPM1 in wheat high-temperature seedling-plant (HTSP) resistance to Pst, the full length of TaRPM1 was cloned, with three copies each located on chromosomes 1A, 1B and 1D. Transient expression of the TaRPM1-GFP fusion protein in Nicotiana benthamiana indicated that TaRPM1 localizes in the cytoplasm and nucleus. Profiling TaRPM1 expression indicated that TaRPM1 transcription was rapidly up-regulated upon Pst inoculation under high temperature. In addition, TaRPM1 was induced by exogenous salicylic acid hormone application. Silencing TaRPM1 in wheat cultivar Xiaoyan 6 (XY 6) resulted in reduced HTSP resistance to Pst in terms of reduced number of necrotic cells and increased uredinial length, whereas no obvious phenotypic changes were observed in TaRPM1-silenced leaves under normal temperature. Related defense genes TaPR1 and TaPR2 were down-regulated in TaRPM1-silenced plants under high temperature. We conclude that TaRPM1 is involved in HTSP resistance to Pst in XY 6.