Oligo-dT anchored cDNA-SCoT: a novel differential display method for analyzing differential gene expression in response to several stress treatments in mango (Mangifera indica L.).

Abstract

Differential display is a powerful technique for analyzing differences in gene expression. Oligo-dT cDNAstart codon targeted marker (cDNA-SCoT) technique is a novel, simple, cheap, rapid, and efficient method for differential gene expression research. In the present study, the oligo-dT anchored cDNA-SCoT technique was exploited to identify differentially expressed genes during several stress treatments in mango. A total of 37 primers combined with oligo-dT anchor primers 3side amplified approximately 150 fragments of 150 bp to 1500 bp in length. Up to 100 fragments were differentially expressed among the stress treatments and control samples, among which 92 were obtained and sequenced. Out of the 92 transcript derived fragments (TDFs), 70% were highly homologous to known genes, and 30% encoded unclassified proteins with unknown functions. The expression pattern of nine genes with known functions involved in several abiotic stresses in other species was confirmed by quantitative reverse transcription polymerase chain reaction (qRT-PCR) under cold (4 °C), salinity (NaCl), polyethylene glycol (PEG, MW 6000), and heavy metal treatments in leaves and stems at different time points (0, 24, 48, and 72 h). The expression patterns of the genes (TDF4, TDF7, TDF23, TDF45, TDF49, TDF50, TDF57, TDF91 and TDF92) that had direct or indirect relationships with cold, salinity, drought and heavy metal stress response were analyzed through qRT-PCR. The possible roles of these genes are discussed. This study suggests that the oligo-dT anchored cDNA-SCoT differential display method is a useful tool to serve as an initial step for characterizing transcriptional changes induced by abiotic stresses and provide gene information for further study and application in genetic improvement and breeding in mango.