FIRST REPORT OF CUCUMBER MOSAIC VIRUS INFECTING BOUGAINVILLEA SPECTABILIS COLEUS BLUMEI KALANCHOE BLOSSFELDIANA AND ZINNIA ELEGANS IN IRAN
N. Shahmohammadi, A. Dizadji, M. Koohi Habibi, M. Nateqi
Cucumber mosaic virus (CMV) is the causal agent of diseases in a wide range of host species, causing important economic losses. In 2012, during a survey in the main ornamental- growing areas of Iran, symptomatic leaf samples from different species of plants were collected and tested by DAS-ELISA using a CMV-specific antiserum. Four CMV isolates were obtained from Bougainvillea spectabilis (CMV-Bo1), Coleus blumei (CMV-Co1), Kalanchoe blossfeldiana (CMV-Ka16) and Zinnia elegans (CMV-Zin2). Mechanical inoculation single- lesion isolates from Chenopodium amaranticolor caused similar symptoms on test plants, except for Vigna unguiculata, in which pinpoint necrotic local lesions were induced by Zin2 and large necrotic lesions by the others. A differential local lesion size in V. unguiculata has previously been reported for CMV isolates of subgroup I or II (Palukaitis and García-Arenal, 2003). Zin2 was differentiated serologically using a set of 11 CMV-specific monoclonal antibodies (DSMZ, Germany). Total RNA extracted from infected Nicotiana benthamiana was used in RT-PCR with primers designed in the coat protein (CP) gene of subgroups I and II (Lin et al., 2004). A product of the expected size (638 bp) was amplified from Zin2A using subgroup II primers, while an amplicon of 657 bp was obtained with subgroup I-specific primers. Amplicons were cloned and sequenced. Multiple alignments of CP gene nucleotide sequences of CMV isolates verified that Zin2 (GenBank accession No. KP662628) belongs to subgroup II, while Bo1, Co1 and Ka16 (KP662629, KP662630, KP455737) belong to subgroup I. In Iran CMV subgroup II isolates have previously been reported from cucumber and hoary cress but, to our knowledge, not from four species presently investigated.