Department of Biochemistry and Molecular Biology, Federal University of Parana, Curitiba, Paraná, Brazil.
Department of Cellular and Molecular Biology, Federal University of Parana, Curitiba, Paraná, Brazil.
Sci Rep. 2019 Mar 11;9(1):4041. doi: 10.1038/s41598-019-40600-y.
Three species of the β-Proteobacterial genus Herbaspirillum are able to fix nitrogen in endophytic associations with such important agricultural crops as maize, rice, sorghum, sugar-cane and wheat. In addition, Herbaspirillum rubrisubalbicans causes the mottled-stripe disease in susceptible sugar-cane cultivars as well as the red-stripe disease in some sorghum cultivars. The xylem of these cultivars exhibited a massive colonisation of mucus-producing bacteria leading to blocking the vessels. A cluster of eight genes (bcs) are involved in cellulose synthesis in Herbaspirillum rubrisubalbicans. Mutation of bcsZ, that encodes a 1,4-endoglucanase, impaired the exopolysaccharide production, the ability to form early biofilm and colonize sorghum when compared to the wild-type strain M1. This mutation also impaired the ability of Herbaspirillum rubrisubalbicans M1 to cause the red-stripe disease in Sorghum bicolor. We show cellulose synthesis is involved in the biofilm formation and as a consequence significantly modulates bacterial-plant interactions, indicating the importance of cellulose biosynthesis in this process.
三种β-变形菌属的 Herbaspirillum 能够与玉米、水稻、高粱、甘蔗和小麦等重要农作物形成内生共生关系固定氮。此外，Herbaspirillum rubrisubalbicans 可引起易感甘蔗品种的斑驳条纹病和某些高粱品种的红条纹病。这些品种的木质部大量定植产生粘液的细菌，导致血管堵塞。一组八个基因（bcs）参与 Herbaspirillum rubrisubalbicans 中的纤维素合成。与野生型菌株 M1 相比，bcsZ 基因突变（该基因编码 1,4-内切葡聚糖酶）削弱了外多糖的产生、早期生物膜形成和高粱定植的能力。这种突变还削弱了 Herbaspirillum rubrisubalbicans M1 引起 Sorghum bicolor 红条纹病的能力。我们表明纤维素合成参与生物膜的形成，因此显著调节细菌-植物相互作用，表明纤维素生物合成在该过程中的重要性。
