| Pepper {Capsicum annuum) is an important vegetable and industrial material crop. Pepper production has been recently an effective way for the agricultural production around our country. In the course of culture, however, several biotic and abiotic stresses have negative influence on production and quality of pepper. As the previous research shown, on the one hand plants may be harmed by UV-B, on the other hand, plants will be induced to produce several defense responses as the insects and diseases do. So far it is not completely be understanded about the molecular mechanism of plant defensive response, although there has been lots of researches and reports about the harmful mechanism of UV-B to plants. In this research, we are based on understanding the molecular mechanism of pepper response to UV-B stress, acquiring and analyzing its transcriptome by cDNA-AFLP technique, finding the differential genes that response to UV-B and proving it by using Real Time PCR. The main result is formulated in the following points:1, By using the cDNA-AFLP technique, we got the transcription mapping of pepper response to UV-B and found 208 differential transcript-derived fragments. From the statistical result and the functional classification, it can be found that there were 138 up-regulated TDFs and 70 down-regulated TDFs, and included 10% for Signal Transfermation related protein, 22% for Defense response related protein, 20% for Photosynthesis related Protein, 5% for Protein Metabolism related protein, 2% for Carbohydrate Metabolism related protein, 1% for Active oxygen Metabolism related protein, 11% and 29% for Other functional proteins and Unknown proteins.2, With the total RNA, a cDNA library was constructed with SMARTTM cDNA library kit. Titer of the cDNA library was more than 1×10~6 pfu/mL and the recombinating rate of the cDNA library was about 99%.3, By the PCR Based 96-hole screening method, the cDNA library was screened with designed primers from the sequencing fragments and two genes which might are closely related with the UV-B stress were acquired. The genes were: Chlorophyll a/b binding protein (EU401724) and Cyclophilin-like (EU401723). 4, The expression of two candidate genes was detected and analyzed under the stresses of UV-B,Phytophthora capsici, JA, SA, JA + SA, NaCl, 4℃, mechanical damage and so on by using Real Time PCR. The result was demonstrated that: A. The consequences of the expression and changes from the two genes in pepper under UV-B radiation were totally in accord with the cDNA-AFLP, which also verified the reliability from the consequence of cDNA-AFLP. B. The gene which encoded Cyclophilin-like protein in pepper under UV-B was expressed less than the one from contral pepper totally, however, obviously more than that under the treatment of NaCl and mechanical damage, which indicated that the Cyclophilin-like protein could response to the stress of salty and Phytophthora blight and be involved in related defensive response. The result of Real Time PCR was displayed that the expression of Chlorophyll a/b binding protein was ascending when treated in the 10 minutes and was gradually descending in compare to the contral one as the prolonged time. But it was srongly expressed when the UV-B was removed after 2 hours, and returned to the expression level of the contral gene as the following time, which suggested it may be involved in the molecular mechanicm of the defense and repair under UV-B stress. Obviously, the gene, which encoded Chlorophyll a/b binding protein, was inhibited due to the distinct descending expression under the treatment of Phytophthora blight, JA and the combination of JA and SA.
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