Cloning And Function Identification Of Hmg1 Promoter For Rate Limiting Enzyme Gene Of Natural Rubber Biosynthesis From Hevea Brasiliensis

Natural rubber is very important not only for the national defense but also for the industry. The yield of natural rubber is not keeping up with its demand in our country, and depending on the import. However, the rubber tree needs special clime for its plantation, and there is not enough area to enlarge plantation in our country, so it is urgency to increase the unit yield of natural rubber. Among the three factors (latex production, latex flow and laticifer differentiation) for relation to latex production of rubber trees, latex production namely natural rubber biosynthesis has important impact for increasing the unit yield of natural rubber, and the 3-Hydroxy-3-Methylglutaryl Coenzyme A Reductase is one of the rate limiting enzymes in the pathway of natural rubber biosynthesis. HMGR is encoded by a small gene family comprised of three members: Hmg1, Hmg2 and Hmg3. It is reported by Chye that in comparison to Hmg1 which is more highly expressed in laticifer than in leaf, inducing by ethene, the level of Hmg3 mRNA level is equally abundant in laticifer and leaf, like the promoters of most house keeping genes, lacking TATA box, while the Hmg2 is constitutive expression. So, to study the promoter of Hmg1 is important for theory significance and application value.For identification the expression of Hmg1 gene between latex and leaf, we extract the total RNA of latex and leaf from the rubber tree cultivars RY7-20-59, 7-33-97, then the northern blot analysis shows that the Hmg1 gene is more highly expressed in laticifer, not expression in the leaf. The result is not accordant with what is Chye reported.The 882bp of 5'regulation sequence for Hmg1 is obtained using Genomic Walking from the leaf genome DNA of rubber tree cultivar RY7-33-97, and the core promoters (-49～+1, -236～-186) are predicted by the internethttp://www.fruitfly.org/seq_tools/promoter.html, Besides several typical eukaryotic cis-regulatory elements TATA-motif and CAAT-motif are found in the 5'regulation region, some other important cis-regulatory elements, such as ERE, HSE, CGTCA-motif, WUN-motif and...