First Report of the Association of a Nanovirus with Foorkey Disease of Large Cardamom in India

Abstract

Large cardamom (Amomum subulatum Roxb.) is affected by the serious disease ‘foorkey’, which is of unknown etiology (1). Excessive sprouting and formation of bushy dwarf clumps at the base of mother plants that gradually die, characterize the disease. In surveys in the Sikkim-Darjeeling Hill area during 2002 and 2003, as much as 27% of plants were found to be affected. Electron microscopy of negatively stained, partially purified preparations from field-infected large cardamom plants showed the presence of isometric particles measuring 17 to 20 nm. The causal agent was successfully transmitted by the aphid Micromyzus kalimpongensis Basu, in a persistent manner. Ten randomly selected field samples gave A405 0.1 to 0.23 compared with 0.57 with positive control with enzyme-linked immunosorbent assay using antiserum to an Indian isolate of Banana bunchy top virus (BBTV). A fragment of approximately 850 bp was amplified from the diseased plants using polymerase chain reaction (PCR) with primers 5′-ATGGCGCGATATGTGGTATGC-3′ and 5′-TCAGCAAGAAAACCAACTTTATTC-3′, designed to amplify the putative Rep gene based on the sequences of DNA1 of BBTV. The PCR product was cloned and sequenced (GenBank Accession No. AY 485960) and showed 80 to 82% identity with the corresponding region of DNA1 of BBTV and 47.6 to 48.5% with other recognized nanoviruses. These findings indicate that a nanovirus is associated with ‘foorkey’ disease of large cardamom, which is tentatively named as Cardamom bushy dwarf virus. Reference: (1) P. M. Varma and S. P. Capoor. Indian J. Agric. Sci. 34:56, 1964.

Reconstitution of Authentic Nanovirus from Multiple Cloned DNAs

“…and is present in banana-growing countries in the Asia-Pacific region and Africa (24,52). Recently, abacá bunchy top virus (ABTV) from Southeast Asia has been molecularly characterized (50), and also a single DNA component of cardamom bushy dwarf virus from India was described (41). These two viruses have been proposed as members of the genus Babuvirus (www .ictvonline.org).…”

Technology, Chemistry and Bioactive Properties of Large Cardamom (Amomum subulatum Roxb.): An Overview

“…The primary spread of disease from one area to another is through infected rhizomes and further spread within a plantation by aphids (Raychaudhuri and Chatterjee, 1958). Nano virus is associated with foorkey (Mandal et al, 2004) and the aphid, Micromyzus kalimpongensis is a transmitting vector for virus from the diseased to a healthy plant thereby leading to spread of the disease (Adhikari and Sigdel, 2015). The budget for the improvement on treatment and control over diseases is very high and hence not significantly noticeable to overcome the amount of loss because of foorkey (Mandal et al, 2004).…”

Advances in Small Isometric Multicomponent ssDNA Viruses Infecting Plants

“…The genus Babuvirus included only, Banana bunchy top virus (BBTV). Recently, Abaca bunchy top virus (ABTV) and Cardamom bushy dwarf virus (CBDV) have been reported as new virus species under Babuvirus [60,84,87]. There is only one unassigned species, Coconut foliar decay virus (CFDV).…”

“…ABTV is distributed in Abaca growing regions of the Philippines [87]. CBDV affecting large cardamom is distributed in eastern sub-Himalayan mountains of India [60]. SCSV and MDV occur in Australia and Japan, respectively.…”

“…Nucleotide sequence of Rep gene showed 80-82% identity with that of BBTV and 47.6-48.5% identity with the nanoviruses. Based on this information along with the available biological properties, association of a new Nanovirus, Cardamom bushy dwarf virus (CBDV) was identified with the foorkey disease of large cardamom [60]. Six distinct full-length DNA components encoding putative master-Rep (M-Rep), non-master-Rep, coat protein and three DNA components of unknown function (FrU1, FrU2 and FrU3) were cloned and sequenced, which showed phylogenetic affinity with babuviruses [61,84].…”