Spatial and temporal distribution of ApMV and ApNMV associated with mosaic disease of apple (Malus domestica) to optimize tissue and time for real time detection

Abstract Background: Besides apple mosaic virus (ApMV), apple necrotic mosaic virus (ApNMV) has also been found associated with apple mosaic disease. Both viruses being labile in nature and their titer varies negatively with high temperatures, needs proper tissue as well as time for real time detection within the plants. The present study was carried out to understand the distribution and titre of ApMV and ApNMV in apple trees from different plant parts (spatial) during different seasons (temporal) for optimization of tissue and time for their timely detection.Methods and Results: The RT-PCR and RT-qPCR was carried out to detect and quantify both the viruses in various plant parts of apple trees during different seasons. Depending upon the availability of tissue, both ApMV and ApNMV were detected in all the plant parts during spring season using RT-PCR. During summer both the viruses were detected in only in seeds and fruits, whereas in leaves and pedicel during autumn season. The RT-qPCR results showed that during spring the ApMV and ApNMV expression was higher in leaves, where as in summer and autumn the titre was highest in seeds and leaves respectively. Conclusions: Leaves during spring and autumn, whereas seeds during summer season can be used as detection material via RT-PCR for early and rapid detection of ApMV and ApNMV. This study will help in accurate sampling to index the planting material well in time and will also aid in production of virus free planting material