First report of potato leaf roll virus (PLRV) naturally occurring on jute (Corchorus olitorius) in India.

Abstract

Jute (Corchorus olitorius L.) is an important bast fiber crop that is mainly grown in the Southeast Asian countries like India, Bangladesh, Nepal, China, Indonesia, Thailand, Myanmar, and a few South American countries. In June 2013, symptoms suggestive of a viral disease were noticed on jute (cv. JRO524) in an experimental field of the CRIJAF research farm, Barrackpore, India, and the incidence of the disease was less than 2%. The infected plants showed stunted growth and short height. Mostly the upper leaves elongated with curling and coiling of lamina. Puckering and shoe string effect were also noticed. Petioles and stipules of the affected leaves were exceptionally longer. Although initially the incidence was low, it may spread to larger areas in subsequent years. Because the jute fiber is extracted from the stem, stunted growth and short height would badly affect the fiber yield and quality. Ten symptomatic and ten asymptomatic healthy looking samples were collected from the field. Corchorus golden mosaic begomovirus is common in jute; therefore, all the samples were tested by PCR using JMFL-AF/JMFL-AR, DNA-A component specific primer pair and JMFL-BF/JMFL-BR, DNA-B component specific primer pairs (1). However, there was no amplification. Because the aphid Aphis gossypii was often noticed in the jute field, all the samples were tested by double-antibody sandwich (DAS)-ELISA for common aphid transmitted viruses, e.g., Cucumber mosaic virus, Bean common mosaic virus, Cowpea mosaic virus, Papaya ring spot virus, Potato leaf roll virus (PLRV), Potato virus Y, and Watermelon mosaic virus using commercial diagnostic kits (Agdia). The symptomatic samples showed positive reaction only for PLRV. Five ELISA-positive samples and five asymptomatic healthy samples were used for RNA extraction. Total RNA was extracted by using QIAGEN RNeasy mini kit. RT-PCR was carried out with PLRV CP gene specific primer pair (3) which generated a cDNA amplicon of 627 bp in all ELISA-positive symptomatic samples. PLRV was not detected in symptomless samples. The five purified cDNA products were cloned in a pGEM-T Easy vector (Promega) and were sequenced. One of the five identical sequences was deposited in GenBank (Accession No. KF233880). The consensus sequence was analyzed by NCBI BLAST and found to share 99% similarity with the coat protein sequence of PLRV reference strain (S77421). Nucleotide span and ORF finder (NCBI) analysis indicated the 627-bp PCR amplicon coded part of a coat protein gene that had 100% identity with translated gene product (Protein ID AAB33483). PLRV is a small isometric RNA virus with worldwide distribution belonging to the family Luteoviridae whose natural host range is mainly restricted to solanaceous plants and few plants of other families (2,4). To the best of our knowledge, this is the first report of PLRV naturally occurring on jute (C. olitorius).