Role of Leaf Epicuticular Wax Load and Composition against Whitefly Population and Cotton Leaf Curl Virus in Different Cotton Varieties

Abstract—Current experiment was conducted on existing cotton varieties against Cotton Leaf Curl Virus (CLCuV) and whitefly infection. The objective of this study was to determine the difference in leaf epicuticular wax load and composition of CLCuV resistant and susceptible cotton varieties. Settling behaviour of whitefly in previous studies showed more whitefly population on CLCuV susceptible whereas less on CLCuV resistant cotton plants. Correlation analysis of CLCuV infection with whitefly population and leaf epicuticular wax load was performed. CLCuV infection has significant positive correlation with whitefly population and significant negative correlation with leaf epicuticular wax load. These results depicted more leaf epicuticular wax load and less whitefly attack on G. arboreum as compared to G. hirsutum varieties. It was also hypothesized that resistant cotton varieties may have different wax composition than susceptible varieties. For this purpose, GC-MS analysis of leaf epicuticular wax of both types of varieties was performed. GC-MS results of CLCuV resistant and susceptible cotton plants also showed differences in quantity and composition of leaf epicuticular wax. Based on these results, we can conclude that leaf epicuticular wax acts as a barrier against CLCuV and whitefly infection. Different biochemical compounds present in leaf epicuticular wax along with their quantity, are also responsible for the resistance and susceptibility of G. arboreum and G. hirsutum varieties.