Characterization of rice yellow mottle virus in north-eastern Tanzania
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Date
2015
Journal Title
Journal ISSN
Volume Title
Publisher
The University of Tokyo
Abstract
Rice (Oryza sativa L.) is an important cereal-grain in some African countries and known to be
attacked by Rice yellow mottle virus (RYMV). Rice plants with virus like symptoms were collected from
lower Moshi and other areas in the north-eastern region of Tanzania. RYMV was detected by DAS-
ELISA, RT-PCR and/or electron microscopy from almost all collected samples. Some RYMV isolates
were sequenced and identified as strain S4. Also, three of them, Tz-12-20, Tz-12-22 and Tz-10-36, were
clustered as a new group named S4-mk (Mt. Kilimanjaro). Cluster of S4-mk formed a monophyletic group
of isolates in strain S4-lv reported from the Tanzanian side of the Lake Victoria. However, S4-mk and S4-lv
lineages are separated from each other and S4-mk has the characteristic three amino acid substitutions.
The isolates of S4-mk were also closely related to that of strain S4-mg. Amino acid sequences of the coat
protein of the isolates in group S4-mk showed over 96% identity with those in other strain S4 varieties,
S4-lv, S4-mg and S4-lm. The phylogenetic tree also indicated the possibility of strain S4-mk to have
dispersed from south-western Kenya to north eastern Tanzania. As for the serotyping, followed by
Fargette et al. (2002), these three isolates in S4-mk were classified into serotype 4.
Description
Journal article
Keywords
Phylogenetic analysis, Rice, Rice yellow mottle virus (RYMV), Serotype, Tanzania