Micro-array Analysis of Cold Tolerant Tomato Expressing Nicotiana tabacum Osmotin

Our earlier studies have established improved cold tolerance in the transgenic tomato ( Solanum lycopersicum cv. Pusa Ruby) developed through constitutive over expression of Nicotiana tabacum Osmotin gene. To understand the molecular responses, micro-array analysis was performed in the transgenic and the wild type on cold (4.0 °C) treatment for 2 and 24 h using Affymetrix GeneChip ® Tomato Genome Array. The principal component analysis plots placed the wild type and transgenic in different regions, indicating differential transcript regulation on cold exposure. The differential gene expression analysis performed using pairwise comparison for transgenic and wild type indicated modulation of 307 out of 3770 genes, by 10 or higher fold on cold treatment. Sugar and amino acid metabolism together constituted the maximum of the annotated products of the differentially expressed genes. The results revealed modulation of expression of responsive genes involved in various functions in the transgenic tomato on cold treatment.