Detection and identification of Bean common mosaic virus resistant germplasm in mungbean (Vigna radiata (L.) Wilczek) using serological and molecular diagnostics
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Date
2019
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DIVISION OF PLANT GENETIC RESOURCES ICARāINDIAN AGRICULTURAL RESEARCH INSTITUTE NEW DELHI
Abstract
Mungbean is one of the important pulse crops of India supplies high quality protein
especially for vegetarian population and low socio economic strata of the country. Viral
diseases are the important limiting factors among biotic stresses for successful pulses
production. Bean common mosaic virus (BCMV) is a major threat for successful
production of BCMV. It has wide host range and causes economic yield losses up to
35-98% in common bean. Host plant resistance is the reliable and economic practice of
BCMV management. Germplasm serves as a source of resistant gene, screening of
germplasm for BCMV resistance will provide resistance source which can be used
further used in breeding programmes to develop new cultivars.
A total of 65 mungbean germplasm along with two susceptible and one resistant
check were screened against BCMV both under natural conditions in the field and after
artificial inoculation in controlled conditions. For detection of BCMV, electron
microscopy, Direct antigen coating- Enzyme-linked immunosorbent assay (DACELISA) and reverse transcription-polymerase chain reaction (RT-PCR) were used.
Electron microscopy (EM) revealed the flexuous rod viral particles of 823nm. RT-PCR
protocol was standardized for the detection of BCMV. RT-PCR was standardized with
newly designed three primers pairs (BCMV1, BCMV2 and BCMV3) and annealing
temperature for all the three primers were standardized and amplified PCR products
were sequenced. The PCR products showed 98.9%, 99.3% and 98.9% nucleotide
similarity with BCMV.
Accessions showed various symptoms like mosaic, vein clearing, vein banding,
puckering, leaf curling, and reduction in the lamina of trifoliate leaves. Among the 65
accessions screened for resistance to BCMV in the field under natural conditions and
after artificial inoculation, 50 accessions were found to be immune, four accessions
were resistant, two accessions were moderately resistant, three accessions were
susceptible and six accessions were highly susceptible. Among them accession
IC0148525 and IC568946 were identified as highly susceptible with 83.33% disease
incidence. A total of 50 accessions were found to be immune to the BCMV, which did
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not show any symptoms and EM, ELISA and RT-PCR also did not reveal the presence
of BCMV. Further, DAC-ELISA of seed coat and embryo of 65 accessions revealed
the presence of BCMV in seed coat (27) and embryo (6) including 21 accessions found
immune in the field and after artificial inoculation indicating that these 21 accessions
are also susceptible to BCMV. Therefore, 29 accessions are found to be immune to
BCMV in the present study. State-wise analysis of accessions revealed that accessions
from Andaman & Nicobar Island, Arunachal Pradesh, Assam, Bangladesh, Kerala and
Rajasthan immune/ resistant to BCMV. Accessions from Andhra Pradesh, Bihar,
Himachal Pradesh, Jammu & Kashmir, Jharkhand, Maharashtra and Odisha showed
varied amount of susceptibility to BCMV. Identified resistant accessions can be utilized
in crop improvement programme for breeding resistant cultivars. Standardized RT-PCR
protocol can be used for the detection of BCMV during identification of resistant source
in other legume crops, conservation of BCMV-free germplasm in National Genbank
and during quarantine processing of germplasm imported into the country.
Key words: BCMV, Germplasm, Screening, Resistance, TEM, ELISA, RT-PCR
Description
T-10158
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