S14 - Session P4 - Development of Pepper veinal mottle virus vaccines for cross protection in solanaceous crops by nitrous acid-induced mutagenesis

Authors: Tsung-Chi Chen*, Guan-Da Wang

Tomatoes ( Solanum lycopersicum L.) and peppers ( Capsicum annuun L.) are the most important vegetable and fruit solanaceous crops in the world, with a total planting area of about 7,000 ha in Taiwan. The cultivation of tomatoes and peppers in Taiwan is usually affected by virus diseases due to the lack of effective control measures, and the aphid-borne potyviruses, thrips-borne orthotospoviruses, and whitefly-borne begomoviruses are the main constraints. In this study, a severe strain of pepper veinal mottle virus (PVMV), a Potyvirus member, was used for attenuation by nitrous acid-induced mutagenesis. The expected mild virus strains were screened on the basis of the induction of inconspicuous spots on Chenopodium quinoa leaves and mild symptoms on Nicotiana benthamiana plants. Three stable attenuated mutants, denoted m4-8, m10-1 and m10-11, were obtained from 1769 local lesion selections in ten nitrous acid treatments. Among the mutants, m4-8 has a significant protective effect on wild-type (WT) PVMV in N. benthamiana and tomato plants in greenhouse trials. The accumulation of m4-8 (CP and RNA) in N. benthamiana and tomato plants was significantly lower than that of WT PVMV. Whole-genomic sequence analysis revealed that by comparison with WT PVMV genome, fourteen nucleotide substitutions lead to thirteen amino acid changes within m4-8 genome. Our results showed that m4-8 has great potential as a protector against PVMV in solanaceous crops. The protective effectiveness of m4-8 will be investigated in the field.