Two Kinds Of Different Biotypes Of Brown Planthopper Gene Expression Differences

Brown Planthopper (Nilaparvata lugens Stal)(BPH) has long been one of the most devastating pests to rice crop in Asia, and the susceptible rice cultivars often suffer severe yield loss up to 60% from its damaging. The estimated average annual yield loss from BPH is approximately 20% nationwide in China in recent years. Breeding resistant cultivars has proven to be the most efficient way to control this pest. However, the occurrence of new BPH biotype is a great threat to the application of resistant varieties.In order to verify the molecular mechanism of virulence differentiation of brown planthopper, we analyzed the genes which are differentially expressed in two different Brown planthopper Biotypes or Biotype I and Biotype II by means of fluorescent differential display (FDD). And we applied real-time PCR to validate the results of FDD. We constructed the recombinant plasmids, pET28a-cae-M and Htb-cae-M, and they were respectively expressed in E.coli BL21 (DE3) and Tn5 cell. The following results were obtained:1) Thirty differentially expressed cDNA fragments were obtained from twenty DD-PCR reactions.2) Twenty-two differentially expressed cDNA fragments were amplified in reamplificatinon reactions. About 1/4 of the thirty differentially expressed cDNA fragments could not be reamplified, which might be false positive.3) We cloned and sequenced the differentially expressed cDNA fragments and got the result that 6-2-2 was 543-bp long, 6-1-5 was 517-bp long, 6-4 was 499-bp long, 7-1-1 was 233-bp long, 14-8 was 400-bp long, 6-1-1 was 277-bp long, 15-1-2 was 279-bp long, 2-1-4 was 266-bp long, 3-3-11 was 290-bp long and 8-1-6 was 420-bp long. Among the ten genes, 6-2-2, 6-4, 3-3-11 andl5-l-2 were expressed higher in Biotype II BPH than in Biotype I one while the others were expressed higher in Biotype I BPH. The alignment of these sequences through NCBI BLAST database revealed that 6-2-2 had high homology (Identities =...