Regulation of expression of 3-hydroxy-3-methylglutaryl coenzymeA (HMG-CoA) synthase in Hevea brasiliensis
การแสดงออกของยีน HMG-CoA Synthase ในยางพารา

Pluang Suwanmanee, D. of Biochemistry, F. of Sci., PSU.
Wallie Suvachittanont, Assoc. Prof., D. of Biochemistry, F. of Sci., PSU.
Nualpun Sirinupong, D. of Biochemistry, F. of Sci., PSU.
Corresponding e-mail : swallie@ratree.psu.ac.th

Grant : NSTDA, IDP, Government budget
Presented : The 18th International Congress of Biochemistry and Molecular Biology Beyond the Genome, Birmingham, UK, 16-20 July 2000
Key words : HMG-CoA Synthase, Hevea brasiliensis, rubber tree

A cDNA clone encoding 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) synthase was isolated form a cDNA library which was prepared form the C-serum of rubber latex of Hevea brasiliensis using Arabidopsis thaliana cDNA encoding HMG-CoA synthase as a probe. The nucleotide sequence analysis revealed an open reading frame of 1392 nucleotides which encoded a protein of 464 amino acids with a predicted molecular mass of 5128 Da. The deduced amino acid sequence exhibited strong similarities with plant and mammalian HMG-CoA synthase sequence. Analysis of RNA samples from different tissues of seedling rubber trees showed a higher mRNA level in stem, root, and petiole than in the leaf. In mature rubber trees, a mRNA level higher in latex and petiole than in the leaf was also obtained. The mRNA, activity levels of HMG-CoA synthase and rubber yield were correlated reasonably well. These parameter were higher in RRIM600 clone than in the wild type. Ethylene, used as a stimulant of latex production in rubber trees can induce mRNA and activity level of HMG-CoA synthase in rubber latex. Diurnal variation in mRNA and activity of HMG-CoA synthase in C-serum of rubber latex were observed. Southern analysis sug-gested that there were more than one gene in Hevea brasiliensis. The Hevea gene isolated and char-acterized may be involved in rubber biosynthesis.

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