Nucleotide Sequence of the 3'-Terminal Region of Bean Yellow Mosaic Virus RNA and Resistance to Viral Infection in Transgenic Nicotiana benthamiana Expressing Its Coat Protein Gene.

Abstract

The sequence of 4, 306 nucleotides from the 3'-poly(A) tract of bean yellow mosaic virus (BYMV) RNA has been determined. This sequence contained a single, long open reading frame (ORF), that when compared with amino acid sequences of other potyviruses was expected to encode carboxyl terminus of CI, 6K, NIa, NIb and coat protein (CP). The CP-coding sequence was predicted to be 819 nucleotides in length, encoding a protein of 273 amino acids. To produce transgenic plants resistant to viral infections, the BYMV CP gene was fused to a high expression promoter cassette containing a duplicated enhancer sequence of cauliflower mosaic virus 35S promoter followed by the 5'-untranslated sequence of tobacco mosaic virus RNA. The chimeric gene was introduced into Nicotiana benthamiana by Agrobacterium-mediated gene transfer, and the expression of CP gene was verified by Western blot analysis. Self-fertilized R1 progeny expressing detectable levels of CP showed significant delay in symptom development, as well as an attenuation of the symptoms.