LAUSR

Potato late blight, caused by the oomycete pathogen, Phytophthora infestans de Bary, is one of the most devastating plant diseases in the world. It is of great importance to screen disease resistance germplasms and elucidate the molecular mechanisms underlying the resistance. In a previous study, Huasong 7, a tetraploid potato variety, was identified to possess resistance to multiple P. infestans races at various levels. In the present study, Huasong 7 was inoculated with an incompatible isolate 428–2 and a compatible P. infestans isolate T30–4, and gene expression was profiled at 0, 24, 48, and 72 h post inoculation. The results showed that more gene expression differentiation was observed in the compatible interaction induced by T30–4 than that in the incompatible interaction induced by 428–2. The differentially expressed genes induced by 428–2 were significantly enriched in GO terms associated with immune responses and the regulation of defense responses, as well as KEGG pathways related to antioxidant activities, for example, the glutathione metabolism. In contrast, differentially expressed genes induced by T30–4 were significantly enriched in GO terms associated with transcription, translation, and biosynthesis of macromolecules, as well as disease resistance related KEGG pathways, such as phosphoinositide metabolism, phospholipid signaling system, and receptor-mediated endocytosis. Our findings indicated that Huasong 7 responds to incompatible P. infestans isolate through disease resistance and host defense related pathways; while it responds to compatible isolate T30–4 with basic responses. It is also possible that T30–4 contains other unknown Avr genes. In summary, our study could provide an important reference for a better understanding of potato late blight resistance mechanisms of both compatible and incompatible interactions.