Proteomic analysis of rose powdery mildew Podosphaera pannosa Wallr Fr de Bary interaction and mining of resistance mechanism

Abstract

Rose is amongst the most important ornamental crops worldwide and powdery newlinemildew (Podosphaera pannosa (Wallr.: Fr.) de Bary) is the major disease of rose when newlinegrown in polyhouse or open field. Employing host plant resistance is the best approach to newlinemanage this disease. Identification of resistant genes (R genes) and related resistance gene newlineanalogues (RGAs) helps in selecting specific rose lines in breeding program. Resistance gene newlineanalogues (RGAs) were identified in rose genotypes maintained at ICAR-Indian Institute of newlineHorticultural Research (IIHR). Eleven RGAs (IIHRR13-4R1, IIHRR13-4R2, IIHRR13-4R3, newlineIIHRR13-4R4, IIHRR13-4R5, IIHRR13-4R6, IIHRR13-4R7, IIHRR13-4R8, IIHRR13-4R9 newlineand IIHRR13-4R10) were identified from powdery mildew resistant germplasm line, newlineIIHRR13-4 of ICAR-IIHR.Major defense related genes identified were RPP13, TFs, MAP kinases, GLPs, newlineperoxidase, chitinase, glucan endo-1, 3-beta-glucosidase 2, RLKs and R genes from newlineIIHRR13-4. Gene Ontology (GO) term enrichment and pathway analyses revealed that the newlinetranscriptome of IIHRR13-4 was enriched more with transcripts coding for plant hormone newlinesignal transduction, plant-pathogen interaction, starch and sucrose metabolism, serine and newlinethreonine metabolism, compared to that of susceptible cultivar Konfetti. The proteome newlineprofiles of IIHRR13-4 and Konfetti at 0 and 36 hai of powdery mildew were studied by 2- newlinedimensional electrophoresis and MALDI-TOF-MS.The results confirm the expression of a disease resistance newlineprotein during early stages of powdery mildew infection at IIHRR13-4 and that was not newlineobserved in Konfetti. This also confirms that lack of defense gene expression leads to newlinepowdery mildew susceptibilty in Konfetti. The mechanism of resistance in IIHRR13-4 was newlineconfirmed with the expression of RPP13 and disease resistance protein At1g61300 and newlinethereby R gene mediated response to powdery mildew.