title: Biotic and abiotic stress tolerance in transgenic tomatoes by constitutive expression of S-adenosylmethionine decarboxylase gene.
abstract: Recent findings have implicated the role of polyamines (putrescine, spermidine and spermine) in stress tolerance. Therefore, the present work was carried out with the goal of generating transgenic tomato plants with human S-adenosylmethionine decarboxylase (samdc) gene, a key gene involved in biosynthesis of polyamines, viz. spermidine and spermine and evaluating the transgenic plants for tolerance to both biotic and abiotic stresses. Several putative transgenic tomato plants with normal phenotype were obtained, and the transgene integration and expression was validated by PCR, Southern blot analysis and RT-PCR analysis, respectively. The transgenic plants exhibited high levels of polyamines as compared to the untransformed control plants. They also showed increased resistance against two important fungal pathogens of tomato, the wilt causing Fusarium oxysporum and the early blight causing Alternaria solani and tolerance to multiple abiotic stresses such as salinity, drought, cold and high temperature. These results suggest that engineering polyamine accumulation can confer tolerance to both biotic and abiotic stresses in plants.
authors.affiliation: Plant Polyamine and Transgenic Research Laboratory, Department of Genetics, University of Delhi, South Campus, Benito Juarez Road, New Delhi, 110021 India.
authors.forename: Pranjal
authors.initials: P
authors.lastname: Hazarika
authors.forename: Manchikatla Venkat
authors.initials: MV
authors.lastname: Rajam
keywords: Abiotic stress; Biotic stress; Polyamines; S-adenosylmethionine decarboxylase; Solanum lycopersicum; Spermidine; Transgenic plants