“…first time identified the two codons, at positions 1756 and 1798, under positive selection. Similar results were observed for the cp genes of apple stem pitting virus (Komorowska et al, 2011), grapevine rupestris stem pitting-associated virus (Alabi et al, 2010), sweet potato mild mottle virus (SPMMV) (Tugume et al, 2010), and the P1 proteinase of SPMMV (Tugume et al, 2010), where several codons were under positive selection whereas purifying selection acted on the other sites. Purifying selection could occur by functional constraints during the virus life cycle when interacting with hosts (Schneider and Roossinck, 2000;French and Stenger, 2003), and it is the main evolutionary force (García-Arenal et al, 2001).…”