An Investigation of Apple Chlorotic Leaf Spot (ACLSV) and Tomato Ring Spot (ToRSV) in Some Iranian Pear Gardens

Background and Aims: In spite of a long tradition of fruit-tree growing in all provinces of Iran, information on pear (Pyrus communis) tree viruses is scant. In order to identify of the nature of the virus like symptoms and decline in pear trees, we carried out a survey for the occurrence of four important viruses. Materials and Methods: Leaf samples of pear showing virus like symptoms were collected in three provinces, Iran, in 2013 and 2014 and tested for Apple chlorotic leaf spot (ACLSV), Apple stem pitting virus (ASPV), Apple stem grooving virus (ASGV) and Tomato ring spot (ToRSV) infection by ELISA, using specific antibodies. Results: 39 out of 112 leaf samples were found to be infected by at least ToRSV and ACLSV. ToRSV was detected in the symptomatic samples from all surveyed provinces with infection ranging from 32.4% up to 35.0%; however, the infection of ACLSV was differed between 9.9 to 18.2 %. Infections of ELISA positive samples were confirmed by biological assay. DNA fragments of 580 and 700 bp in size were RT-PCR amplified using specific primers designed according to RdRp and CP genes of ToRSV and ACLSV, respectively which indicated 96 and 92 % highest identities with available sequences of ToRSV and ACLSV isolates in GenBank, respectively. Conclusion: This analysis provides, to our knowledge, the first demonstration of pear trees infection with ACLSV and ToRSV in Iran. Early detection of viral pathogens and accurate diagnosis, are undoubtedly essential for controlling the spread of virus and ensuring production of healthy plant reproductive material for further cultivation.