Quantification of sugarcane yellow leaf virus in sugarcane following transmission through aphid vector, Melanaphis sacchari

Abstract

Yellow leaf (YL) caused by Sugarcane yellow leaf virus (SCYLV) is a serious constraint to sugarcane production in India and currently the disease epidemics occur on many of the susceptible varieties under field conditions. Detailed studies were conducted on the virus transmission by sugarcane aphid Melanaphis sacchari in sugarcane by inoculating virus-free meristem derived from micro- propagated plants of sugarcane cv Co 86032 with viruliferous aphids. Virus transmission was confirmed through RT-PCR assays and subsequently SCYLV population was established through RT-qPCR. A maximum of 22.3 x103, 3.16 x106 and 4.78 x106 copies of SCYLV-RNA targets was recorded in the plants after 7, 180 and 300 days respectively. This study showed that the aphid species Melanaphis sacchari acts as an effective vector to transmit SCYLV from one plant to another in sugarcane fields in India. The relative standard curve method in RT-qPCR efficiently detected the increment in SCYLV copy numbers in sugarcane after virus inoculation