产harpin的成团泛菌工程菌308R(pCPP430)遗传稳定性的研究

GENETIC STABILITY OF A RECOMBINANT PANTOEA AGGLOMERANS STRAIN 308R(pCPP430) CAPABLE OF PRODUCING PLANT RESISTANCE INDUCING PROTEIN HARPIN

成团泛菌工程菌３０８Ｒ（ｐＣＰＰ４３０）带有梨火疫欧文氏杆菌的与过敏反应和致病性有关的基因簇 （ｈｒｐ），可以产生能诱导植物抗病性的蛋白质ｈａｒｐｉｎ。该工程菌在ＬＢ液体培养基中生长５０代后，带有重 组质粒ｐＣＰＰ４３０的细胞占总菌量的 １％，带有载体ｐＣＰＰ９的细胞为４６％。工程菌喷雾到番茄叶面，保湿条 件下叶面菌量维持在 １０５ｃｆｕ／ｃｍ２以上，其中带有 ｐＣＰＰ４３０质粒的菌维持在 ４０％以上，带有 ｐＣＰＰ９载体的 菌维持在８０％以上。因此，携带ｈｒｐ基因簇的质粒ｐＣＰＰ４３０在宿主菌中是不稳定的。文中讨论了改进工 程菌遗传稳定性的途径。

The genetic stability of Pantoea agglomerans 308R(pCPP430), a recombinant strain capable of producing the plant resistance inducing protein harpin, was studied both in medium and in plant under antibiotic-free conditions. After successive growth in LB medium for 50 generations, only 1% of the cells still retained the plasmid pCPP430, in comparison with 46% of the vector pCPP9. After sprayed onto the leaves of tomato, the recombinant strain maintained a population density of 10~5cfu /cm2 when kept under high humidity. 40% cells of this population contained the plasmid pCPP430. It was shown that plasmid pCPP430 was unstable due to inadequate partition. Strategies for improving its genetic stability were discussed.