The viral infection dramatically affects plant physiology, including photosynthesis, respiration, carbohydrate levels and can contribute to genome instability, disturbances of the meiotic and mitotic processes, modification in gene expression. At the basis of genetic changes can by postulated that the infection may triggers various variations, which can later be inherited.
The impact of viral infection in progeny was assessed on the basis of four genotypes of tomato (local cultivar Elvira, spontaneous form S.pimpinellifolium, the varieties Craigella (Tm-22/Tm-22) and Craigella (Tm-1/Tm-1). For inducing pathogenesis the plants were infected mechanically at the stage of 3-4 leaves with tomato aspermy virus (TAV, isometric virions, RNA genomic nucleic acid component) or tobacco mosaic virus (TMV, rod-shaped particle, RNA genomic nucleic acid component). For the following investigation were used the generation obtained from seeds formed under viral pathogenesis. The tomato progenies were healthy and present absence of viral particles.
For evaluation the intrapopulational polymorphism was used PCR technique, based on the virtually universal presence of a tRNA complement as a reverse transcriptase primer binding site (PBS) in LTR retrotransposons. Total DNA was extracted from leaves by a modified CTAB method. PCR was performed according to the length of amplicons and specificity of primers. The products of amplification were divided into 1.5 % agarose gel by electrophoresis (5-8 V/cm) in a migration buffer of Tris/borate EDTA with ethidium bromide. In order to identify the efficient protocol, were screening as molecular markers 20 iPBS primers, been selected 2 that gave intragenomic polymorphism.
The product of amplification based on primers iPBS presented qualitative differences in molecular profile. The frequency of unique fragments with intragenomic specificity was dependent on viral infection, and also by morphological aspect described in frame of same experimental variant.
The evaluation of electrophoregrams of the amplification products with primers iPBS established monomorphic and polymorphic fragments with variable ratio in dependence of viral infection and induced modification. The higher number of fragments was identified using 17 iPBS primer in Craigella (Tm-1/Tm-1) presented in control 10 amplicons. In TAV variant has been show also 10 polymorphic fragments. The differences in profiles were find in TMV variants in dependence of morphological aspects of plants. The progenies derived from infected plants exhibited at different ontogenetic stages of some genotypes (S.pimpinellifolium infected with TAV, c.Elvira infected with TMV and TAV) modifications of stem, leaf distribution, shoot branching, conversion of components of flowers and the fruit shape or size. Such modification as regeneration (Rg1), fab2 (fascinated inflorescence), described in generation of the infected plants of the Craigella (Tm-22/Tm-22), were accompanied by unique polymorphic fragments. Similar results were described also between the plants with modification of locule number (lc) and fascinated (f) identified in progenies of S.pimpinellifolium descendants from TAV infected plants. Similar results had been described and for other evaluated tomato varieties. The molecular analysis with 20 iPBS primer exhibited less fragments (2-3 polymorphic and 1-7 monomorphic).
Must be notified, that in the progenies of TMV and TAV plants, complementary molecular differences were quantified values modifications of biometric traits, confirmed statistically for the most host-pathogen combinations.