Genetics, Mechanism, and Regulation of Cellulose Synthesis in A. tumefaciens

根癌农杆菌与宿主细胞的孵育导致细菌合成纤维素纤维。这些纤维将细菌牢牢地固定在宿主细胞表面。利用不能合成纤维素的转座子突变体，纤维素合成所需的基因正在被鉴定和鉴定。正在确定这些基因产物的亚细胞定位和参与纤维素合成的步骤，并研究宿主细胞对细菌纤维素合成的调节。虽然有一些关于纤维素合成机制的信息，但对任何生物体中参与其合成的基因和基因产物知之甚少。此外，根癌农杆菌中的纤维素合成是一个有趣的例子，它通过与细菌结合的宿主细胞的存在来调节参与细菌黏附的胞外多糖的合成。纤维素是高等植物细胞壁中含量最丰富的聚合物，在全球范围内具有巨大的重要性。其他生物(除高等植物外)也能合成纤维素，更易于生物化学和分子操作。植物病原菌根癌农杆菌能合成纤维素，而纤维素似乎在其与寄主的相互作用中起着重要作用。关于任何系统中纤维素合成的机制，可获得的信息很少，几乎对所涉及的基因或它们的调节一无所知。根癌农杆菌提供了一个很好的系统来研究纤维素合成所需的机制和基因，不仅在这种有机体中，而且在高等植物中也是如此。

Incubation of Agrobacterium tumefaciens with host cells results in synthesis by the bacteria of cellulose fibrils. These fibrils serve to anchor the bacteria firmly to the host cell surface. Using transposon mutants which are unable to synthesize cellulose, the genes required for cellulose synthesis are being identified and characterized. The subcellular localization of these gene products and the steps involved in cellulose synthesis are being determined and the regulation of bacterial cellulose synthesis by the presence of host cells examined. Although there is some information available on the mechanism of cellulose synthesis, there is little knowledge of the genes and gene products involved in its synthesis in any organism. In addition, cellulose synthesis in A. tumefaciens is an interesting example of the regulation of the synthesis of an exopolysaccharide involved in bacterial adhesion by the presence of the host cells to which the bacteria bind. Cellulose is the most abundant polymer in the cell walls of higher plants and is of enormous importance globally. Other organisms (besides higher plants) are also capable of synthesizing cellulose and are more amendable to biochemical and molecular manipulation. The plant pathogen, Agrobacterium tumefaciens, synthesizes cellulose which appears to play an important role in its interaction with its host. There is very little information available about the mechanism of cellulose synthesis in any system and almost nothing is known of the genes involved or their regulation. A. tumefaciens provides a good system in which to examine the mechanisms and genes required for cellulose synthesis not only in this organism, but higher plants as well.