Morris PF, Bone E, Tyler BM
Department of Biological Sciences, Bowling Green State University, Bowling Green, Ohio 43403 (P.F.M., E.B.).
Plant Physiol. 1998 Aug;117(4):1171-8. doi: 10.1104/pp.117.4.1171.
We have investigated the role of the isoflavones daidzein and genistein on the chemotropic behavior of germinating cysts of Phytophthora sojae. Hyphal germlings were shown to respond chemotropically to daidzein and genistein, suggesting that hyphal tips from zoospores that have encysted adjacent to the root may use specific host isoflavones to locate their host. Observations of the contact response of hyphal germlings were made on several different substrates in the presence and absence of isoflavones. Hyphal tips of germlings detected and penetrated pores in membranes and produced multiple appressoria on smooth, impenetrable surfaces. Hyphae that successfully penetrated the synthetic membrane were observed to grow away from the membrane surface. The presence of isoflavones in the medium surrounding the hyphal germlings did not appear to alter any of those habits. Daidzein and genistein did not inhibit germination or initial hyphal growth at concentrations up to 20 &mgr;M.
我们研究了异黄酮大豆苷元和染料木黄酮对大豆疫霉萌发囊肿趋化行为的作用。结果表明，菌丝幼体对大豆苷元和染料木黄酮有趋化反应，这表明在根部附近形成囊肿的游动孢子产生的菌丝尖端可能利用特定的宿主异黄酮来定位其宿主。在有和没有异黄酮存在的情况下，在几种不同的底物上观察了菌丝幼体的接触反应。菌丝幼体的菌丝尖端检测并穿透了膜上的小孔，并在光滑、不可穿透的表面上产生了多个附着胞。观察到成功穿透合成膜的菌丝从膜表面生长离开。菌丝幼体周围培养基中异黄酮的存在似乎并未改变这些习性中的任何一种。在浓度高达20μM时，大豆苷元和染料木黄酮均未抑制萌发或初始菌丝生长。
