Small G Protein StRab5b positively regulates potato resistance to Phytophthora infestans

Abstract

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 StRab5b 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 Phytophthora infestans 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 N. benthamiana and StRab in potato respectively. StRab5b expression varied among different potato tissues and varieties, and was induced by P. infestans infection. Transiently ectopic expression of StRab5b in N. benthamiana enhanced its resistance to P. infestans, whereas, silencing of StRab5b and its homologous gene facilitated pathogen infection in potato and N. benthamiana respectively. Furthermore, stable expression of the StRab5b gene in potatoes enhanced its redox-stress response capacity, as manifested by the accumulation of H2O2 in infected leaves and subsequent increase in the activity and expression of ROS scavenging enzymes, thereby attenuating the development of P. infestans and ultimately reducing the lesions on infected potato leaves. In addition, the LOX gene transcripts and JA level were upregulated rapidly after inoculation with P. infestans. Collectively, our results suggest that StRab5b positively regulates the resistance against potato late blight (PLB) via JA-mediated defense signaling pathway.

The beneficial endophytic microbes enhanced tobacco defense system to resist bacterial wilt disease

“…Besides, our results also showed that defense enzymes of SOD, PPO, POD, PAL, CAT and β-1,3-GA exhibited high activities in diseased roots and stems (Fig. 6), which indicated that defense enzymes participated in the signaling pathway of the plant-pathogen interactions [56]. When plants were invaded by pathogens, reactive oxygen species (ROS) rapidly accumulated and caused programmed cell death and hypersensitive response of plants.…”

Secondary Metabolites, Other Prospective Substances, and Alternative Approaches That Could Promote Resistance against Phytophthora infestans

“…However, most of these candidates for MAS need to be validated in dedicated mechanistic studies. A recent study showed that an accumulation of Small G protein StRab5b reduced the lesions on infected potato leaves [205], but it remains to be seen how this alteration impacts the yield and other economically important traits. The most interesting part of the proteome resides in post-translational modifications.…”

“…The effectiveness of these endogenous S. tuberosum peptides against P. infestans is unclear, and further research is needed. However, foreign or synthetic antimicrobial peptides have been found to provide resistance against P. infestans, including syringomycin E and syringopeptin 25A from Pseudomonas syringae [205], Stellaria media hevein [215], and the synthetic peptide NoPv1 [216].…”