Sub-Lethal Effects of Partially Purified Protein Extracted from (Balsamo) and Its Presumptive Role in Tomato ( L.) Defense against Whitefly ( Genn.).

Plants rely on various physiological and molecular defense mechanisms against biotic stresses such as herbivore insects. Many entomopathogenic fungi synthesize protein molecules that can trigger these plant defenses. This laboratory study characterized the bioactivity of a partially purified protein derived from (ARSEF 2860) against whitefly, (Hemiptera: Aleyrodidae), which is an economically important pest of agricultural and horticultural crops worldwide. Different concentrations (i.e., 0.021, 0.042 and 0.063 μM) of fungal protein were bioassayed to determine their sub-lethal effect on the survival percentage and fecundity rate of on tomato () plants. In addition, the putative role of this partially purified protein in the defense mechanisms of plant was assessed through the expression analyses of important genes related to salicylic acid (SA)-and jasmonic acid (JA)-associated pathways using RT-qPCR. Results revealed a significant suppression of the survival percentage and fecundity rate of by the fungal protein. Lowest survival (41%) was recorded for the highest concentration of protein (0.063 μM), whereas mean survival for the other two protein concentrations (0.042 and 0.021 μM) were 62 and 71%, respectively. Likewise, the highest and lowest mean fecundity rates were observed for the control and the highest protein concentration (i.e., 3.3 and 1.8 eggs day female, respectively). Furthermore, the exogenous application of -derived protein on tomato plants strongly up-regulated the SA-related genes (PAL, PR1, BGL2 and EDS1) and slightly up-regulated the JA-related genes (AOC, AOS, OPR3 and LOX) as compared to the control plants. These findings demonstrate the putative role of this partially purified protein fraction in inducing systemic resistance in the tomato plants against , suggesting its further purification and characterization to be used as novel biological pest control tool against and other sap-sucking insect pests.