Molecular charecterization of taro bacilliform virus (TaBV)
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Date
2017
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Department of Plant Biotechnology, College of Agriculture, Vellayani
Abstract
Taro is one of the world’s oldest food crop maintained by farmers for
millennia and it has continued to spread throughout the world, as an important crop in
Asia, Pacific, Africa and the Caribbean. Viral pathogens are one of the important
factors threatening production of this vegetatively propogated crop. Taro viruses are
poorly characterized, which is a hindrance to the safe movement of germplasm. The
overall aim of this study was to detect the Taro bacilliform virus infecting taro and to
characterize the virus at molecular level. Serological detection methods were not
employed for the detection of TaBV. Molecular analysis with specific primers (TaBV
like sequences) identified a new member among the badnavirus, Taro bacilliform
CH virus, which was not previously detected in India.
During the study 55 samples from different fields of CTCRI are selected to
identify the different symptoms of Taro bacilliform virus infection. The symptoms
and occurrence of TaBCHV is still not clear eventhough the samples shows different
type of infections with infections in non-symptomatic ones also. Molecular analysis
with badnavirus specific primers and further confirmation with PNG BadnaF/PNG
Badna R reveals the presence of Taro bacilliform CH virus. It reveals that the
RT/RNase H region was highly similar for Taro bacilliform and Taro bacilliform CH
virus with <80 % similarity. Sequence and phylogenetic analysis confirms the
sequences were more closely related to TaBCHV and exhibited 100 % similarity to
TaBCHV isolates TaBCHV-1 and TaBCHV-2. From the Seven pair of primers were
specifically designed inorder to characterize the whole genome of Taro bacilliform
CH virus three pair of primers were used to successfully characterize the virus
partially.
To identify the phylogenetic relationship of the sequenced samples with that
of available accessions, dendrograms were made using MEGA 5.0 software and the
tree showed that sequences has variability eventhough lies within the group. It s clear
from the study that the genome sizes of TaBCHV isolates, TaBCHV-1 and TaBCHV-
2 (Gen Bank Accession Nos: KP710178 and KP710177) were 7,641 bp, and it was
within the badnavirus genomic range. The two islates almost shared about 98%
genomic nucleotide identity. With other reported badnaviruses the genome sequence
of TaBCHV-1 and TaBCHV-2 showed similarity to RYNV (44.1 %) and Fig
Badnavirus (55.8 %)
Description
PG
Keywords
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