Explorando a variação genética natural das espécies selvagens relacionadas ao tomateiro no modelo Micro-Tom (Solanum lycopersicum L. cv Micro-Tom)

Abstract

Exploring natural genetic variation from wild species related to tomato in the Micro-Tom model (Solanum lycopersicum L. cv Micro-Tom) Tomato wild species evolved in a wide range of latitudes, from the south of Ecuador to the north of Chile, which comprise different habitats and are a source of natural genetic variation. This diversity is commonly used in tomato breeding, especially for the introgression of genes for resistance to pathogens and, recently, for fruit quality. Although natural genetic variation usually has an adaptive significance, which means that it may have evolutionary implications, it is still poorly explored in basic research. For the intensive utilization of this resource, it is necessary to perform large scale crosses and backcrosses between wild species and cultivated tomato. Aiming to this purpose, we used the miniature tomato cultivar, cv Micro-Tom (MT), which can growth in the same minimum requirements of the Arabidopsis thaliana model. Using MT one can adequately explore the natural genetic variation of wild species with less time and space requirements. In addiction, phenotypical alterations are more evident in MT, since one can easily visualize the whole plant. Thus, alleles hitherto unknown were isolated from tomato wild related species, leading to distinct phenotypes, such as pink-salmon fruits from S. neorickii, opaque fruit surface from S. chmielewskii and dark green fruits from S. galapagense. The MT model seems to be particularly adequate for the isolation of major genes and QTLs of great effects. Thereby, we had isolated a S. pimpinellifolium locus that increases the number of flowers per inflorescence, from 7 to 11, in MT. Being the tomato a cultivated plant, the alleles obtained in the wild species, besides to be useful for genetic and physiological studies, can be used in pre-breeding programs.

Estudo da variação genética natural em tomateiro (Solanum lycopersicum) para o processo de absorção de nitrogênio

“…Espécies de tomateiro selvagens apresentam uma grande diversidade genética, especialmente aquelas espécies auto-incompatíveis, como S. chilense e S. peruvianum (RICK, 1988). A variação genética presente nas espécies silvestres tem sido investigada intensivamente para identificação de características específicas a serem exploradas no melhoramento genético da cultura (RICK, 1988;PIOTTO, 2007).…”