MRNA Expresseion Profile Of Brassica Parachinensis In Response To Plutella Xylostella Feeding And Gene Cloning

Plants have evolved complex responses to phytophagous insects that can be either constitutive or induced upon herbivore attack during the long period of coevolution with pests. The molecular mechanism of the induced response has gained increasing popularity in recent years. But seldom have efforts investigated the the characteristics of genes related to insect feeding in vegetable crops.To better understand the molecular mechanisms of vegetable crop–insect interactions, we employed a novel approach - Solexa sequencing system - to examine the differentially expressed gene profile of Brassica parachinensis Bailey subjected to Plutella xylostella feeding by sequencing all of the mRNAs. We finally obtained 7,773 short tags that represented the differentially expressed genes induced by P. xylostella. Alignment of the 7,773 tags was then performed with all the unigenes of Brassica in GenBank as reference genes, and 125 tags were found to have matched results. Analysis with BLAST nr revealed that these 125 genes encode for serine/threonine protein kinase, MYB transcription factor, zinc-finger protein, universal stress protein, copper/zinc superoxide dismutase precursor, heat shock protein, chlorophyll a/b-binding protein, photosystem II protein, s-adenosylmethionine synthetase, glyceraldehyde-3-phosphate dehydrogenase, ADP-glucose pyrophosphorylase, pectinesterase-like protein, plasma membrane aquaporin, sulfotransferase family protein, histone H3, etc., expected 17 unknown function and 12 without any significant similarity genes. Many of these genes have been previously shown to be induced during plant responses to certain stresses.These genes are related to plant photosynthesis, energy metabolism, signal transduction, gene expressed regulation, stress response, carbon and fatty acid metabolism, protein metabolism, growth and development, cellular component, membrance and transport, according to gene ontology and pathway analysis.We also attempted to clone some important genes induced via RACE and two nucleotide fragments were obtained. Sequencing analysis and homology searches determined that these two nucleotide fragments represented a metallothionein-like protein and a photosystem II polypeptide protein.