Document Type : Research Article
Authors
1
Aassistant Professor of Plant Pathology, Plant Protection Research Department, Yazd Agricultural and Natural Re-sources Research and Education Center, AREEO, Yazd, Iran
2
Professor of Plant Pathology, Plant Protection Department, Bu-Ali Sina University, Hamedan, Iran
3
Associate Professor of Plant Pathology, Plant Protection Research Department, Fars Agricultural and Natural Re-sources Research and Education Center, AREEO, Zarghan, Iran
4
Professor of Plant Pathology, Department of Agricultural Sciences, Plant Pathology, Alma Mater Studiorum, Univer-sity of Bologna, Italy
Abstract
Alfalfa witches’ broom (AWB) is a limiting factor for alfalfa growth and production in Iran, especially in the tropical regions of the country. AWB phytoplasma strains from two severely affected areas, Chahgeer (Abarkooh, Yazd province) and Juyom (Larestan, Fars province), were compared for main biologic, serologic and molecular characteristics. Based on disease symptoms in alfalfa farms, Chahgeer and Juyom AWB (CAWB and JAWB, respectively) strains were not differentiable. In dodder inoculated periwinkle and tomato plants JAWB phytoplasma induced stronger little leaf compared to the one induced by CAWB phytoplasma. In these experiments the two JAWB and CAWB phytoplasma strains are confirmed as vectored by different leafhopper species, Orosius albicinctus and Circulifer haematoceps respectively. Based on 16S rRNA gene and 16S-23S intergenic spacer region sequences, CAWB and JAWB were not differentiable, however no serologic relationship was observed between the two phytoplasmas in ELISA and DIBA tests using polyclonal antibodies prepared against each of them. Due to the lack of serological relationship, different insect vectors and induction of different symptoms in common host plants, CAWB and JAWB phytoplasmas should be considered as two different AWB strains both belonging to 16SrII-C subgroup.
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