Effect of Light to Expression Control of Eucalyptus KORRIGAN Promoter in Tobacco

Abstract

Cellulose is the most important structural component of plant cell wall. Due to the enormous economic benefit of tree cellulose for paper, pulp, lumber and packaging industries, understanding the mechanism of cellulose biosynthesis is important for the sustainability of these industrial businesses. KORRIGAN gene (Kor) encodes a plasma membrane bound enzyme, endo–1, 4-D-glucanase, which is member of cellulose biosynthesis genes. This research focused on the analysis of the promoter region of the Kor gene, promoter structure and gene expression control under dark and light conditions. The Kor promoter region of E ucalyptus grandis, E. camaldulensis, and E. urophylla were cloned and sequenced. Sequences were analyzed by alignment against the E. glandis genome sequences using a ClustalW 2.1 program. The gene expression control of Kor promoter was tested, recombinant plant transformation plasmid, pCAMBIA1304, with the Kor promoter fused to the reporter gene,-glucuronidase (gusA) was transferred to tobacco (Nicotiana tabacum) and the gene expression controls were analyzed by real time PCR. Results revealed that Kor promoter nucleotide sequences from E. grandis, E. camaldulensis, and E. urophylla, are high similar to E. grandis  Kor promoter database at the percentages of 97, 95 and 96 respectively. Two transgenic tobacco lines,15k2 and 15K3, showed the specific expressions of the reporter gene, gusA, but limited only in the vascular tissues, and the levels of gene expression were regulated by light, Under lighting conditions of 8 and 16 hrs. expression reduction from those under dark condition of 29%, 36%, 36% and 31% respectively were observed.