Department of Plant Pathology and Microbiology, University of California, Riverside, CA, USA.
Mol Plant Microbe Interact. 2013 Jun;26(6):676-85. doi: 10.1094/MPMI-12-12-0283-R.
Xylella fastidiosa is a gram-negative, xylem-limited bacterium that causes a lethal disease of grapevine called Pierce's disease. Lipopolysaccharide (LPS) composes approximately 75% of the outer membrane of gram-negative bacteria and, because it is largely displayed on the cell surface, it mediates interactions between the bacterial cell and its surrounding environment. LPS is composed of a conserved lipid A-core oligosaccharide component and a variable O-antigen portion. By targeting a key O-antigen biosynthetic gene, we demonstrate the contribution of the rhamnose-rich O-antigen to surface attachment, cell-cell aggregation, and biofilm maturation: critical steps for successful infection of the host xylem tissue. Moreover, we have demonstrated that a fully formed O-antigen moiety is an important virulence factor for Pierce's disease development in grape and that depletion of the O-antigen compromises its ability to colonize the host. It has long been speculated that cell-surface polysaccharides play a role in X. fastidiosa virulence and this study confirms that LPS is a major virulence factor for this important agricultural pathogen.
韧皮部坏死菌是一种革兰氏阴性、木质部局限的细菌，它会引起一种致命的葡萄藤疾病，称为皮尔氏病。脂多糖（LPS）构成了大约 75%的革兰氏阴性菌的外膜，并且由于它主要显示在细胞表面，因此它介导了细菌细胞与其周围环境之间的相互作用。LPS 由保守的脂 A-核心寡糖成分和可变的 O-抗原部分组成。通过靶向一个关键的 O-抗原生物合成基因，我们证明了富含鼠李糖的 O-抗原对表面附着、细胞-细胞聚集和生物膜成熟的贡献：这些是成功感染宿主木质部组织的关键步骤。此外，我们已经证明，完全形成的 O-抗原部分是导致葡萄皮尔氏病发展的重要毒力因子，并且 O-抗原的耗尽会削弱其在宿主中定植的能力。长期以来，人们一直推测细胞表面多糖在韧皮部坏死菌的毒力中起作用，本研究证实 LPS 是这种重要农业病原体的主要毒力因子。
