Molecular Characterization And Expression Analysis Of A Strictosidine Synthase Gene From Ophiorrhiza Japonica And A Mannose-binding Lectin Gene From Monstera Deliciosa

Camptothecin (CPT) is a monoterpene indole alkaloid isolated from the deciduous Chinese happy tree. Now, it has become one of the anticancer and antiviral drugs from plant. Camptotheca.acuminata grows very slowly and the CPT was isolated from the original plant source which is very limited, while the demand for CPT is rapidly increasing in recent years. It was very excited that the CPT had been reported in O.japonica in recent. In this work, it is the first time to report the cloning and characterization of the STR gene from the Rubiaceae plant Ophiorrhizajaponica. And the expression, regulation and effects of the inductor were also carried out.The homoptera insect is one of the important factor to the breakdown of crops, had a great variety and also a wide disoperation. During the last few years great progress has been made in the plant anti-insect gene engineering, which provide a new way to control the plant diseases and insect pests. Nowadays a great of the researchs indicates that the lectin has a great effect on the anti-insect, especially to the homoptera insects. This is the firstly report to emphasized the molecular cloning, sequencing and partially characterisation of a lectin from leaves of an ornamental plant Monstera deliciosa. The major experiments from this work were as the following:1 A new full-length cDNA encoding strictosidine synthase, which catalyzes a committed step in camptothecin biosynthetic pathway, was isolated from young leaves of Ophiorrhiza japonica for the first time. The full length of OjSTR was 1258 bp and contained a 1062 bp open reading frame (ORF) encoding a deduced protein of 353 amino acid residues. Sequence analyses showed that OjSTR had high homology with other STRs from some plants which produce TIAs. Phylogenetic tree analysis showed that OjSTR had closest relationship with STR from O.pumila. Tissue expression pattern analysis revealed that OjSTR constitutively expressed in all the tested tissues at different levels, which was high in flower, moderate in leaf and root, low in stem. Expression profiles under plant defense signals such as methyl jasmonate (MeJa) and salicylic acid (SA) were investigated, and the results revealed that expression of OjSTR was all induced, implying that OjSTR was high elicitor responsive.2 Construction of plant expression vector. Based on the cloning of Ophiorrhiza japonica strictosidine synthase, a pCABIA 1304~+ plant expression vector contained OjSTR gene had been made which was driven by the CaMV35S promoter. The vector was transferred into Agribacterium tumefaciens C58C1.3 This is the first time to clone a monocot mannose-binding lectin from Monstera deliciosa in Arceae. The full-length cDNA of Monstera deliciosa agglutinin (MDA) consisted of 1186bp and contained a 852bp ORF encoding a 283 amino acid protein. Bioinformatics analysis results clearly indicated that MDA belongs to the monocot mannose-binding lectin family, which contains 2 putative mannose-binding sites (QDNVY) per subunit. RT-PCR analysis results indicate that MDA expression was tissue-specific which is only expressed in the leaves, not in stems and roots.4 A pCABIA 1304~+ plant expression vector contained MDA gene, which was driven by the CaMV35S promoter, was constructed and transferred into Agribacterium tumefaciens EHA105.