Influence of different SAR elicitors on induction and expression of PR-proteins in Potato and Muskmelon against Oomycete pathogens

Abstract

Two cultivars each of potato namely; Kufri Badshah, Kufri Jyoti and muskmelon namely; Kajri and Punjab Hybrid were treated with varying concentrations of four different elicitors for induction of systemic acquired resistance (SAR) against Phytophthora infestans causing late blight in potato and Pseudoperonospora cubensis causing downy mildew in muskmelon. Attempts were made to induce SAR with application of various SAR elicitors as spray i.e. Jasmonic acid (JA), Salicylic acid (SA), Benzothiadiazole (BTH) and Beta Amino butyric acid (BABA). These elicitors were sprayed on 3-week-old sprouts and effect on defence related proteins along with late blight and downy mildew severity was studied. Leaf samples were collected up to 7 days post treatment and used for estimation of total proteins. Sporangial solution (4.0 × 104 sporangia per ml) was sprayed after 1 week of elicitors spray. Per cent disease severity was recorded at 14 days post inoculation. SA, JA, BTH and BABA caused statistically significant (at 5% level) increase in total soluble protein in leaf samples. The best treatments for maximum induction of proteins were 500 μM each of SA, JA, and BTH and 50 mM for BABA. SDS–PAGE electrophoresis confirmed that exogenous application of JA, SA, BABA and BTH resulted in the induction of PR proteins of low molecular size along with some other proteins in both potato and muskmelon, which helped in induction of SAR against oomycete pathogens.