木麻黄青枯菌的根表吸附及根内增殖与其致病性关系

对 3个不同致病的青枯菌菌株和 7个不同抗病性的木麻黄无性系苗的研究得出 ,各菌株对寄主根表吸附量具有显著差异 ,吸附量与致病性呈负相关 :各菌株在寄主根内的增殖量差别明显 ,增殖量与致病性呈正相关。病菌脂多糖 (LPS)对幼苗根的预处理 ,可使其供体菌的吸附量减少5 8.5 %　 97.3% ,但胞外多糖 (EPS)对供体菌的吸附量无明显影响。洗去EPS和LPS的菌体较完整菌体对根表的吸附量减少 6 3.3%　 74 .2 %。而仅洗去EPS的菌体对根表的吸附有所增加 ,最高达19.1%。各菌体SDS PAGE电泳图谱显示出一定差异 ,其中强毒菌株 6 0 1B具有Rf=0 .35的特异谱带。结果表明青枯菌对木麻黄的致病性与其在寄主根表的吸附情况和在根内的快速增殖具有密切关系。LPS在此病理系统中 ,起着细菌识别因子的作用 ,EPS对LPS进行掩盖 ,二者都是病菌致病性的重要因子

The Relationship between Pathogenicity of Pseudomonas solanacearum and Its Adsorption on the Root Surfaces and Propagation inside the Roots of Casuarina Clone Seedling

The experiments conducted on 3 isolates of P.solanacearum and 7 Casurina clones revealed that the adsorption of bacterial isolates to the host root surfaces differed significantly, a negative correlation between the adsorption amount and the pathogenicity existed; The propagation of 3 isolates within the roots also varied greatly, and a strongly positive correlation existed between the propagation amount and pathogenicity. The pretreated Casuarina ramets with LPS sharply reduced the adsorption of subsequently inoculated bacteria by 58 5% 97 3%, but EPS pretreated ramets did not show any apparent change. The bactcrial cells free of both EPS and LPS lost their adsorption amount by 63.3% 74.2%in comparison to the intact bacteria. However, the EPS free only bacteria slightly increased their adsorption up to 19.1%. Electrophoresis pattern of 3 isolates through SDS PAGE also showed difference with a special Rf=0.35 band occurred for the most virulent isolate 601B. It is concluded that the pathogenicity of P. solanaearum to Casuarina is associated with its adsorption amount on the host root surfaces and especially the rapid propagation capacity inside the roots. LPS plays a role of bacterial cognon in the recognition between the pathogen and host while EPS covers or inhibites this process of LPS. Both LPS and EPS are all important factors that affect the pathogenicity of P. solanacearum.