EXPRESSION ANALYSIS OF CYP82E GENES ASSOCIATED WITH TSNA IN N. ATTENUATA DATA HUB

Abstract

Tobacco is a high value commercial crop for varied traditional end uses smoking, chewing, hookah etc. apart from their medicinal values. Of late, the ill effects of tobacco use is becoming the major issue of concern. The health associated risks of tobacco consumption are majorly attributed to TSNAs, these are the nitrosated products of Nicotine and nornicotine, the major secondary metabolites reported in tobacco. The process of nitrosation is mediated by a key enzyme N-demethylase, which is encoded by CYP gene family. Among the various members of CYP family CYP82E genes are known to be the key functionaries in the regulation of TSNA. The expression these genes in the native state in various tissue and in response to various external cues will aid in understanding their regulation. In this regard an insilico expression analysis was carried out with the known CYP82E gene in the expression data base of Nicotiana attenuata, a close wild relative of N. tabacum. The NaDH currently hosts collections of predicted protein coding sequences of two recently sequenced Nicotiana species, and their functional annotations, 222 microarray datasets from 10 different experiments, a transcriptomic atlas based on 20 RNA-seq expression profiles and a metabolomic atlas. It provides a centralized platform for integrating and visualizing genomic, phylogenomic, transcriptomic and metabolomic data. The BLAST analysis of the candidate CYP genes with NaDH data hub revealed their corresponding gene identifiers which were further utilized for their expression analysis in transcriptome experiments. The CYP82E4 and E10 genes have identifier with more than 90% similarity (NIATv7_g20333.t1). In the micro array data, it was shown that the expression of CYP82E Id got slightly reduced in response to coronatine spray in treated plants compared to control. When plants were challenged with M.sexta neonates a lepidopteran pest the CYP82E Id expression got reduced in wild type. In herbivore attack it has shown strong expression in roots compared to leaves. The transcriptomic data in RNA sequencing experiments also suggests the prominent expression of genes in roots compare to other parts of the plants. In other expression datasets the CYP82E Id genes have shown differential expression. It indicates that CYP82E Id genes of TSNA shows tissue specific expression and the external cues like chemicals and microbes have relatively low effect on the regulation of these genes.