PCR Based Diagnosis of Rice Tungro Bacilliform and Spherical Virus from Infected Plants and Insect Vectors

Rice tungro disease, one of the major constraints for rice production in South and Southeast Asia, is caused by a combination of two viruses: Rice tungro spherical virus (RTSV) and Rice tungro bacilliform virus (RTBV). The disease is characterized by typical symptoms produced in rice plants; however, reliance on symptoms for the detection of disease and presence of viral particles is not always correct. The present study was undertaken to utilize the polymerase chain reaction (PCR) and RT-PCR techniques to diagnose the RTBV and RTSV particles, respectively. Primers were designed from highly conserved regions of viral genomes to amplify the ORF-I and ORF-IV regions of RTBV and CP3 genetic region of RTSV. The detection method was standardized and validated using tungro-infected leaf samples collected from Cuttack (Odisha), Puducherry UT, Coimbatore, Kanyakumari (TN), Patancheru and Rajendranagar (Andhra Pradesh). Insect vectors (green leaf hopper, Nephotettix spp.) were collected from virus infected plants maintained in glass house. All the three primers used in PCR and RT-PCR were found reliable in detecting the virus particles in insects also.