Impact of biorational pesticides and response of annexin gene expression in tomato (Solanum lycopersicum) and capsicum (Capsicum annum L.) in biotic stress management under greenhouse condition

Abstract

Protected cultivation of high value cash crops such as capsicum and tomato is gaining momentum
in recent times. Among various diseases and pests; bacterial wilt, thrips and root knot nematodes
are recurrent threats to its production. Biorational pesticides such as agricultural spray oil and
azadirachtin are more acceptable than conventional insecticides as they are known to be sufficiently
active against pest populations and are relatively safer to beneficial organisms. The experiment was
conducted on relative efficacy of agricultural spray oil, azadirachtin and combination of both (1%)
for the management of these three different types of biotic stresses on tomato and capsicum under
protected cultivation. Results revealed that in all the tested insecticides, the integrated treatments
were most effective in comparison to the individual interventions. To investigate common signaling
mechanism of response towards these stressors, we carried out RNA expression analysis of an
annexin gene. Annexins belong to a family of membrane and calcium (Ca2+) binding proteins which
can characteristically bind membrane phospholipids in a reversible, Ca2+-dependent and independent
manner. Here we report that the expression of annexin is induced in response to three biotic stress
treatments of the crops viz bacterial wilt, thrip infestation and root knot nematode infection. Results
show potential evidence that modulation of a single signaling protein can be useful in management
of three different and common biotic stressors in tomato and capsicum.