Molecular basis of plant viral virulence; the complete nucleotide sequence of an attenuated strain of tobacco mosaic virus

Abstract

The total genome sequence of L₁₁A, an attenuated strain of tobacco mosaic virus (TMV), has been determinea. This strain is able to multiply in tomato plants without inducing any remarkable symptoms, but to protect them from later infection with virulent TMV strains. When compared with the recently published total genome sequence of TMV L (the virulent ancestrastrain of L₁₁A) ten base substitutions were found in the L₁₁A genome. Seven of these occurred in the third letters of in-phase codons and did not influence amino acids. Only three, which were in the common reading frame for both the 130K and 180K proteins, resulted in amino acid changes. Together with the result of the partial sequence of RNA of L₁₁, an intermediate strain in sequential isolation from L to L₁₁A, it is observed that one base at the nucleotide position 1117 is changed from L to L₁₁ and two bases at the positions 2349 and 2754 are changed from L₁₁ to L A.