Differential Gene Expression In Melon (Cucumis Melo L.) Induced By Salicylic Acid (SA)

Salicylic acid is an endogenous small phenolic compound. As a signal molecular, it plays an important role in the metabolic process of regulation. Salicylic acid has been found to induce a variety of plant biotechnology category (viruses, fungal and bacterial diseases) and non-biological category (high and low temperature, high salinity and drought) resistant. Some melon (Cucumis melon.L) with 3 leaves was treated with 1mmol/L SA. After four days of treatment, it was compared with the melon without treated by SA. It investigated the variation of resistance-related genes induced by SA using mRNA Differential Display technology and lay a solid foundation for establishing expressed sequence tags (ESTs) and studies their function in future.1 Both Trizal and RNA Extracted Kit can extract high-quality RNA from the melon leaves. Trizal method is simple, fast, inexpensive and high quality RNA extraction. The disadvantage of the RNA Extraction Kit is the high prices, and compared with Trizal it spends a long time. However, the quality of RNA extracted by RNA Extraction Kit is higher than Trizal.2 In this test, Because of polymorphisms, band uniform distribution, etc, a total of 27 random primers had been chosen. Then both random and anchored primers were used to DDRT-PCR amplification in melon cDNA. Altogether 19 differential bands of four days after treatment were observed and recovered from the agarose gel, among them 8 differential bands were cloned.3 Sequence analyses showed:cDNA3-4-1: has the 83% identity with the putative heat shock factor protein (hsf8) mRNA. hsf8 induced by SA, which might have an impact on the expression of heat shock protein hsp70. hsp70 is good for the maintenance of protein structure, stability and which has played a positive role in intracellular environment.CDNA1-23-1: has a TGACG sequence. A large number of studies about PR-1 gene regulatory sequences found that there was a SA inducible factor in Arabidopsis: TGACG is a conserved sequence, which is necessary for the PR-1 gene expression. TGA protein belongs to bZIP transcription factor. It can be integrated into the downstream PR-1 TGACG promoter sequence, also can be combined with the upstream NPR1, and thus provide a direct link between PR-1 and NPR1gene expression.Other Cloned gene sequence did not show the high homology with known Stress-related or other disease-related genes. Through reverse Northern blotting, positive fragments were obtained; the full-length gene should be obtained by RACE technology.