Transgenic resistance by N gene of a Peanut bud necrosis virus isolate of characteristic phylogeny

• Published in: Virus genes 2009-06, Vol.38 (3), p.445-454
• Main Authors: Venkatesan, S., Raja, J. A. J., Maruthasalam, S., Kumar, K. K., Ramanathan, A., Sudhakar, D., Balasubramanian, P.
• Format: Article
• Language: English
• Subjects: Arachis hypogaea; Biomedical and Life Sciences; Biomedicine; Immunity, Innate; Lycopersicon esculentum; Medical Microbiology; Nicotiana - genetics; Nicotiana tabacum; Nucleocapsid Proteins - biosynthesis; Nucleocapsid Proteins - genetics; Phylogeny; Plant Diseases - immunology; Plant Diseases - virology; Plant Sciences; Plants, Genetically Modified - genetics; Plants, Genetically Modified - immunology; Plants, Genetically Modified - virology; RNA Interference; RNA, Viral - genetics; Sequence Analysis, DNA; Sequence Homology; Solanum lycopersicum - virology; Tospovirus; Tospovirus - genetics; Tospovirus - isolation & purification; Virology; Wisconsin
• ISSN: 0920-8569; 1572-994X
• DOI: 10.1007/s11262-009-0342-5

The nucleocapsid protein ( N ) gene of a Tospovirus devastating tomato crop in the south Indian state of Tamil Nadu was cloned and characterized. The high identity of the cloned sequence to a Peanut bud necrosis virus (PBNV) tomato isolate (97.8/99.6% nucleotide/amino acid) and a PBNV peanut isolate (94.4/96.3% nucleotide/amino acid) identified the Tospovirus as an isolate of PBNV, designated PBNV Coimbatore tomato (PBNV CT) isolate. Phylogenetic analysis of PBNV CT N gene provided useful insights into the movement and evolution of PBNV within Indian Territory. The characteristic phylogeny of PBNV CT N gene implied its potential to be an efficient transgene to confer effective PBNV resistance on crop plants. The efficacy of PBNV CT N gene in conferring PBNV resistance was studied by generating tobacco ( Nicotiana tabacum L. cv Wisconsin) lines transgenic to the sense or antisense version of the gene. Several transgenic lines showed transgenic mRNA and/or protein accumulation, ranging from very high to undetectable levels, accompanied by different degrees of PBNV resistance. The undetectable or very low levels of transgene transcripts in certain PBNV-resistant sense or antisense N gene transgenic lines suggested RNA-mediated resistance by post-transcriptional gene silencing (PTGS) mechanism. However, PBNV resistance of certain transgenic lines with high levels of N gene transcripts was suggestive of possible operation of RNA-mediated non-PTGS mechanism(s) of resistance in those lines. Moreover, the high levels of N protein in certain PBNV-resistant sense N gene transgenic lines suggested protein-mediated resistance. The results predict the potential of PBNV CT N gene to confer effective PBNV resistance on tomato and other economically important crops.