AUTHOR=Tian Zaimin , Zhang Zhiwei , Kang Liru , Li Min , Zhang Jian , Feng Yan , Yin Jiang , Gong Xuechen , Zhao Jun 

TITLE=Small G Protein StRab5b positively regulates potato resistance to Phytophthora infestans

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.1065627

DOI=10.3389/fpls.2022.1065627

ISSN=1664-462X

ABSTRACT=<p>Rabproteins are the largest members of the small G protein family and are widely distributed in eukaryotes. It comprises eight subfamilies and is responsible for regulating vesicle transport, plant growth and development, and biotic and abiotic stress responses. In this study, the small G protein gene <italic>StRab5b</italic> was cloned from potato, and its biological information, expression profile and induced expression level, overexpression and gene silencing were examined on regulating potato resistance to <italic>Phytophthora infestans</italic> using PCR, qPCR and Virus-induced gene silencing (VIGS). Our results indicate that the amino acid of StRab5b shows the highest and lowest homology with NbRab5b in <italic>N. benthamiana</italic> and StRab in potato respectively. <italic>StRab5b</italic> expression varied among different potato tissues and varieties, and was induced by <italic>P. infestans</italic> infection. Transiently ectopic expression of <italic>StRab5b</italic> in <italic>N. benthamiana</italic> enhanced its resistance to <italic>P. infestans</italic>, whereas, silencing of <italic>StRab5b</italic> and its homologous gene facilitated pathogen infection in potato and <italic>N. benthamiana</italic> respectively. Furthermore, stable expression of the <italic>StRab5b</italic> gene in potatoes enhanced its redox-stress response capacity, as manifested by the accumulation of H<sub>2</sub>O<sub>2</sub> in infected leaves and subsequent increase in the activity and expression of ROS scavenging enzymes, thereby attenuating the development of <italic>P. infestans</italic> and ultimately reducing the lesions on infected potato leaves. In addition, the <italic>LOX</italic> gene transcripts and JA level were upregulated rapidly after inoculation with <italic>P. infestans</italic>. Collectively, our results suggest that <italic>StRab5b</italic> positively regulates the resistance against potato late blight (PLB) <italic>via</italic> JA-mediated defense signaling pathway.</p>