R. Selvarajan, V. Balasubramanian, B. Mandal
doi: 10.4454/JPP.V97I3.011
Alpinia galanga (family Zingiberaceae), commonly called greater galangal or blue ginger, is a rhizomatous herb distributed in various parts of India and throughout Southeast Asia. In a garden of the Indian Agricultural Research Institute (New Delhi), 90% of the plants exhibited spindle-shaped yellow or light green streaks in the interveinal tissues and midribs. Based on symptoms and leaf dip preparations that revealed flexuous filamentous particle of ca. 750×12 nm, infection by the potyvirus Banana bract mosaic virus (BBrMV) was suspected. Antigen- coated plate (ACP)-ELISA with a general potyvirus antiserum (DSMZ, Germany) reacted positively, whereas there was no reaction with an antiserum to BBrMV raised at ICAR-National Research Centre for Banana (Tiruchirappalli). Total RNA extracted from symptomatic and healthy leaf tissues using a RNeasy plant mini kit (Qiagen, USA) was tested by RT-PCR, using Chen et al. (2001) degenerate potyvirus-specific primers that amplify a ca.1.7 kb fragment from the 3' genome end (FP: 5' GGNAAYAAYAGYGGNCARCC 3; RP: 5' GTTTTCCCAGTCACGAC(T)15 3’). A product of 1.649 kb was amplified from symptomatic but not from healthy plants, which was cloned and sequenced (GenBank accession No. KM198742), revealing 87-94% and 91-94% identity at the nucleotide and amino acid level, respectively, with Bean yellow mosaic virus (BYMV) isolates from various crops. In ACP- ELISA using a polyclonal antiserum to BYMV (NBPGR, New Delhi), 10 infected leaf samples tested positive, whereas healthy sample were negative. Thus, the symptoms observed in A. galanga, which resemble those elicited by BBrMV in A. purpurata in Hawaii (Wang et al., 2010) are caused by BYMV. To the best of our knowledge this is the first report of the natural occurrence of BYMV in A. galanga in India.