| The brown planthopper (BPH) is an important rice pest, the adults possess wing dimorphism:long and short-winged. Under natural conditions, deterioration of host nutrition and high population density is inclined to yield long-winged worms; while rich host nutrition and low population density is inclined to yield short-winged. Long-winged adults is capable of migration and fertility is weak; short-winged adults have fast development, strong fertility, great harm, but can not migrate. Researching on molecular responses of BPH under deterioration of host nutrition and high population density condition, is of great significance to reveal the underlying causes of BPH disaster.Our study used the ripening rice and created a high population density environment, to establish a nutrition deteriorating stress condition (NDSC) to BPH; while used the tillering stage rice and created a low insect population density environment, to build a nutrition rich comfortable condition (NRCC). Compared the different expressed genes of BPH under two conditions, then got responsive genes in BPH by environmental stress. The main results obtained are as follows:1,Under NDSC (the host was the ripening rice, high population density) and NRCC (the host was the tillering stage rice, low population density), we got two kinds of worm samples, each worm samples included 8 period of larva from 2 to 5 instar.2,Transcriptome Sequencing of BPH:Sequenced transcriptome of BPH through Solexa and got a total number of 1,682,583,750 base pairs,76406 Unigene were obtained by assembling. After blastx comparison between Unigene sequences and NR, Swiss-Prot, KEGG, and COG database, we got the Unigene annotation and made the COG and GO functional classification. In addition, there also finished analysis of the KEGG pathway and predicted protein-coding frame (CDS). Transcriptome Sequencing of BPH completed a large-scale sequencing on transcription level of genes, and provided a reference sequence for Expression Profiles Sequencing of BPH.3,Differential Expression Profiles Sequencing analysis:We sequenced two libraries:the second day of 3rd instar nymphs under NDSC (ND3.2) and the second day of 3rd instar nymphs under NRCC (NR3.2). After sequencing, we respectively got 2.9 million and 3.0 million clean tag, among which there were respectively 71,672 and 83,592 differential clean tag. We compared clean tag with the reference gene database, annotated the only clean tag compared to just one gene, while obtained the standardization of gene expression. Resulting from the differential Expression Profiles Library ND3.2 and NR3.2, we selected 1203 up-regulated and 1341 down-regulated genes.4,We chose 6 categories of genes from differentially expressed genes which had close relationship to the environmental stress response of BPH, they were about lipid metabolism, carbohydrate metabolism, amino acid metabolism, wing and muscle development, hormone metabolism and ovarian development pathway, respectively accounted for 58,34,58,15,7 and 8 for a total of 180 genes, And statistics the differential express level of these genes in each category. We selected relatively higher differential and higher expression genes from these 6 categories:respectively accounted for 6,2,3,3,3 and 2,19 genes in total.5,Verified these 19 genes through real-time PCR, obtained the gene expression under NDSC and NRCC. The results showed differential Expression Profiles Analysis was consistent with the results of real-time PCR. |
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