Approaches to the expression of mel gene in Pseudomonas sp.

• Main Authors: Yang,Shi Yu, 楊適宇
• Other Authors: Hsu,Yuan Hsun;Liu,Yu Tien
• Format: Others
• Language: zh-TW
• Published: 1995
• Online Access: http://ndltd.ncl.edu.tw/handle/77890005990408273953

碩士 === 文化大學 === 生物科技研究所 === 83 === Pseudomonas sp. are aggressive colnizers of the rhizophere of various crops and some of them have a broad spectrum of antagonistic activity against plant pathogens.Then production of antifungal compounds has been regarded of the main mechanisms involved in antagonism. One of the antifungal compounds, named pyrrolnitrin, has been proved to be the key antibiotic in controlling fungal pathogens in vitro and in soil environments. Pyrrolnitrin is a phenylpyrrole antibiotic with a wide range of antifungal activity. It causes mycelial deformities and inhibition of conidiation in phytopathogenic fungi. However it is readily decomposed by the U.V. irradiation because of the existence of such a chemically unstable moiety as pyrrol ring in its molecule. Based on the reasons mentioned above, we consider it is necessary to protect pyrrolnitrin from U.V. damage in developing a longer-lasting Pseudomonas-type biofungicide. Firstly, the coding sequence of mel gene was successfully subcloned to an Escherchia coli plasmid, pGEM-3Z, and the mel gene could express well by using the SP6 promoter of pGEM-3Z. When harboring the plasmid pYHL-694 bearing mel gene, E.coli JM109 can produce melanin pigment after 24 hours incoubated at 37℃ on TYT medium. Finally, we have successfully transferred the mel gene to the pseudomonads by using the brosd- host-range plasmid,RSF1010; however, the expression of mel gene in the microorganism did not observed yet.