Investigation, molecular and biological identification of Citrivirus citri [Citrus leaf blotch virus (CLBV)] in satsuma mandarin and kumquat plants in the Çukurova region

A member of the Citrivirus genus in the Betaflexiviridae family, Citrus leaf blotch virus (CLBV) has a 41 kDa coat protein (CP) and a single-stranded, positive-sense RNA genome with 8747 nucleotides. CLBV causes graft incompatibility, especially in Nagami kumquat and calamondin plants grafted on citrange rootstocks. This study investigated graft incompatibility symptoms observed in kumquat and Satsuma mandarin trees from the Çukurova region, with 143 samples analyzed for CLBV presence. In the collected samples was determined using RT-PCR, transmission electron microscopy (TEM) and biological indexing. RT-PCR analyses targeted code protein (CP), movement protein (MP), and RNA-dependent RNA polymerase (RdRp) regions, yielding amplicons of 438 bp, 675 bp and 456 bp respectively, on 1.5% agarose gels. The rate of infection was 37.14%. TEM confirmed CLBV by visualizing 960 nm virion particles in kumquat, Etrog citron, and Nicotiana spp. Biological indexing exhibited chlorotic blotching on Dweet tangor leaves, stem pitting in Etrog citron, and stunting with internode shortening in Nicotiana spp. seedlings. Sequencing of ten isolates deposited in GenBank under accession numbers OQ718432, PP726108, PP726109, OQ718433, PQ818280, PP726107, OQ718434, PQ818276, PQ818283, PQ818277, PQ818284, PQ034506, PQ818285, PQ818278, PQ818286, PQ818279, PQ818287, PQ818280, PQ818288, PQ818281, PQ818289 and showed 96–99% similarity to NCBI others CLBV sequences. The isolates identified in this study were reported as the first report for Türkiye. Key Words: CLBV, Nagami kumquat, Satsuma, Cukurova, Türkiye