Internal quality characterization and isolation of lycopene specific genes from tomato

Abstract: Tomato (L. esculentum Mill), a popular vegetable in tropics is an excellent source for vitamin A, C, carotenoids and other health related components. It tops the list of industrial crops because of its outstanding processing qualities. It is valued for both its fresh and processed forms. Biochemical analysis in different wild species, varieties and hybrids of tomato showed the wild species, Lycopersicon pimpinellifolium LA 1593 to be a rich source for lycopene specific genes. Partial cDNA of lycopene specific Phytoene desaturase gene TNAU P was isolated from L. pimpinellifolium LA 1593 by RT-PCR technique. Sequence analysis of the partial cDNA showed 99.6% similarity with already available Phytoene desaturase gene from L. esculentum. Also, the sequence showed considerable homology with Phytoene dehydrogenase, Zeta carotene desaturase and Phytoene desaturase genes from Gentian, Oryza, Momardica, citrus and pea. The high intensity of the amplified product in L. pimpinellifolium coupled with 99.6 % homology to L. esculentum inferred that the level of expression of Phytoene desaturase is more in L. pimpinellifolium. Isolation of Phytoene desaturase genes can be further exploited to produce transgenic plants with increased content of lycopene by transferring the genes from wild species to cultivars.