Host-targeted salt stress affects fitness and vector performance of bird cherry-oat aphid (Rhopalosiphum padi L.) on wheat

Abstract

Salinity is becoming a limiting factor for crop production, particularly in arid and semiarid areas all around the world. This phenomenon can adversely affect both plant integrity and herbivorous insects. Herein, we assessed the bottom-up effects of four salinity levels (3.1 [control], 6.0, 10 and 12.0 dS/m) on the life parameters of viruliferous bird cherry-oat aphid (Rhopalosiphum padi L.) and the aphid transmission of Barley yellow dwarf virus-PAV (BYDV-PAV) to wheat host. The results revealed that nymph longevity and adult pre-oviposition period of the aphids fed on salinity-stressed plants were significantly increased, while adult longevity, gross reproductive rate, net reproductive rate, intrinsic rate of increase and finite rate of increase of the aphids on plants challenged with salinity levels of 10 and 12.0 dS/m were significantly reduced. Also, survival rate and life expectancy of viruliferous R. padi remarkably decreased on wheat plants under 10 and 12.0 dS/m salinity. The R. padi-mediated transmission of BYDV-PAV to salinity-stressed (10 and 12.0 dS/m) wheat plants was significantly reduced. Moreover, the biochemical assays showed a significant increase in biosynthesis of phenolics and free proline within wheat plants challenged with salinity stress. Based on these findings, it can be concluded that salinity stress negatively influences life parameters of viruliferous R. padi, possibly through induction of phenolics and free proline within the salinity-stressed plants, and the aphid transmission of BYDV-PAV to wheat host.