Dettection of Viral and Vroid Diseases Associated with Citrus ( Citrus spp) Cultivations inKurunagala District, Sri Lanka

Abstract

Citrus refers to a group of trees and shrubs belonging to the Rutaceae family, which is rich in nutrients and bioactive compounds. Some economically important citrus species are grown in various regions in Sri Lanka. Viral and viroid diseases are the major challenges for citrus production in Sri Lanka. Information on citrus viruses and viroids is scanty and outdated in Sri Lanka. No proper survey has been carried out to identify the different viruses present. This study aims to identify the viral and viroid diseases associated with citrus cultivations and chatacteize the viruses associated with citrus cultivations in Kurunegala district, Sri Lanka. For the detection of viral and viroid diseases, symptomatic leaf samples exhibiting symptoms of yellowing, leaf curling, vein clearing and stunted growth were tested by serological and molecular based techniques. Triple Antibody Sandwich ELISA (Compound ELISA) was performed for the detection of Cinus tristeza virus (CTY) and 76 positive samples were detected out of 100 samples in Kurunegala district. Furthermore, their identity was confirmed by RT-PCR using specific primers (CTV -ARl8F and CTV -AR18R) and expected band size at 51 1 bp. Molecular detection by RT- PCR was conducted for detection of Citrus tristeza virus (CTY), Citrus vein enation virus (CVEV), Cinus yellow mosaic virus (CYMY), Citrus yellow vein clearing virus (CWCV), Cinus bent leaf viroid (CBLYd), Hop stunt viroid (HSVd), and Citrus viroid 1(CVd I LSS). Presence of the CTV was confirmed and amplified PCR products of CBLVd, and CVd I LSS were obtained for further confirmation. For the molecular charactertzation of viral and viroid diseases, Citrus tristezs vlrzs sequence was confirmed with 99% of sequence identity over 464 base pairs and phylogenetic analysis reveatred genetic variations among the Citrus tristeza virus pIS gene sequences and Citrus vein enation virus. These findings demonstrated the urgent need for continuous surveillance and effective disease management strategies to mitigate the impact of viral and viroid infections on citrus crops. Furthermore, the study offered crucial insight into the molecular detection of citrus pathogens in Kurunegala district to contribute to the development of sustainable disease control strategies for enhancing citrus productivity.