DETECTION OF PRUNUS NECROTIC RINGSPOT VIRUS (PNRSV) IN APRICOT AND CHERRY AND ITS POTENTIAL ELIMINATION AT NURSERY STAGE

Abstract

Aims: Detection of prunus necrotic ringspot virus (PNRSV) in apricot and cherry and its potential elimination at nursery stage Study design:  Laboratory work Place and Duration of Study: Lab experiments were conducted at Plant Virology Lab, department of Plant Pathology, DR YS Parmar University of Horticulture and Forestry, Nauni, Solan (HP) during apricots and cherries active growing season of 2020–2021. Methodology: Leaf samples exhibiting typical symptoms were collected from the marked plants in the selected nurseries and carried to the laboratory in separate polythene bags in an ice box to keep the leaf samples fresh for serological detection of ilarviruses via alkaline phosphatase (ALP) based direct antigen coating (DAC) and double antibody sandwich-enzyme linked immune sorbent aasay DAS-ELISA Results: Apple mosaic virus (ApMV) and Prunus necrotic ringspot virus (PNRSV) were found to be associated with the majority of apricot and cherry cultivars' notably symptomatic plants, as confirmed by DAC-ELISA. Out of total 10 plants each of apricot and cherry, 6 plants of apricot and 8 plants of cherry were infected with Ilarviruses thus confirming the association of Ilarvirus. Additionally, DAS-ELISA provided conclusive evidence that among Ilarvirus, PNRSV was more common than ApMV in the infected apricot and cherries. Out of total 10 plants each of apricot and cherry, 6 plants of apricot and 8 plants of cherry were infected with PNRSV. Further, in order to select virus-free clones for apricot and cherry nurseries, serological indexing of evidently healthy plants of significant cultivars of major apricot and cherry cultivars was also carried out using DAS-ELISA. The results indicated that Harkot cultivar of apricot at Experimental Farm, Department of Fruit Science at Dr. YS. Parmar University of Horticulture and Forestry, Nauni, Krishi Vigyan Kendra, Kandaghat, PCDO Gaura and Kashyap nursery were found to be completely free from infection of PNRSV. Conclusion: Given that apricots and cherries are frequently used as seedling rootstock for commercial cultivation of apricots and cherries in India, serological indexing is extremely significant. Since PNRSV is a graft transmissible pathogen, it spreads from rootstock to scion. If either the scion or the stock has an infection with PNRSV, the virus will spread throughout the plant. Therefore, it is crucial to choose healthy seedling rootstock. The significance of serological methods in cultivating robust cherry and apricot cultivars in the nurseries has been emphasized by the DAS-ELISA tests carried out in these investigations.