Analysis Of PAMP Triggered Immunity Against Potato Late Blight Based On Proteomics Technology

Potato is the fourth largest crop in China,which plays an important role in the maintenance of food security in China.However,late blight caused by Phytophthora infestans seriously threatens the production of potato.Since pathogen associated molecular pattern(PAMP)is very conserved,PAMP triggered immunity(PTI)can provide more durable resistance to late blight for potato.INF1 is one of the most well characterized PAMPs in oomycete secreted by Phytophthora infestans.CF is a liquid culture filtrate of Phytophthora infestans,which mainly contains INF1 as well as other types of PAMPs.In this study,two proteomics techniques namely,isobaric tags for relative and absolute quantitation(iTRAQ)and sequential windowed acquisition of all theoretical fragment ions(SWATH),were used to quantify the protein in Nicotiana benthamiana after INF1 and CF induction,respectively.Then the data were collected for bioinformatics analysis to explore the mechanism of PAMP triggered immunity of potato late blight.The main results are as follows:1.A total of 2964 proteins have been identified in Nicotiana benthamiana at 8 h after INF1 induction by iTRAQ,of which 32 proteins were differentially expressed,with 15 up-regulated and 17 down-regulated.2.Then eight up-regulated proteins were selected for further study.By virus induced gene silencing(VIGS)assay and following agroinfiltration of INF1,it was found that the ATP dependent transporter(K4CBY0)and 60 S ribosomal protein(O24114)were essential to the immune response triggered by INF1.3.The SWATH technology was used to analyze proteins in Nicotiana benthamiana at 0h,8h,12 h,24h and 48 h after CF induction.A total of 4401 proteins have been identified,of which 1771 proteins were differentially expressed at least at one time point of 8h,12 h,24h and 48 h,compared with the protein expression at 0h after CF induction.As a result,984 proteins were up-regulated and 799 were down-regulated,among them 12 were both up-regulated and down-regulated at different time points.4.Then the identified 1771 differentially expressed proteins were annotated by gene ontology(GO).It was found that they were mainly located in plastids,followedprotein complexes,cytosol,cytoplasm and mitochondria.Through the activity of ion binding and redox,they were mainly involved in the intracellular biosynthesis,small molecule synthesis,nitrogen metabolism and stress response,as well as some proteins involved in cellular immunity and apoptosis,and other disease related biological processes.5.Through KEGG analysis,some differential proteins were possibly involved in plant-pathogen interaction,Ca2+ signal transduction and MAPK signal,oxidative phosphorylation,protein transport,phenylalanine metabolism and so on.Some of the important proteins known to be involved in PTI resistance,such as BSK1,SGT1,HSP90 and NtCDPK2,are identified.Other proteins newly identified in the related signaling pathways are likely to play an important role in plant PTI resistance.