Differential Responses of Phytophthora sojae to Seed Exudates of Host Soybean and Non-host Maize

In order to clarify the differential response of Phytophthora sojae to the seed exudates of host soybean and non-host maize and understand the relationship between seed exudates and host selectivity of Phytophthora sojae, non-host maize Suiyu 23 and susceptible host soybean Sloan seed exudates were collected to measure their influence on mycelial growth, formation and germination of oospores, chemotaxis, encystment and germination of zoospores of Phytophthora sojae. The results showed that nonhost maize seed exudates exhibited repellency to zoospores of Phytophthora sojae, it also could significantly inhibited Phytophthora sojae mycelial growth, formation of oospores compared with the control;compared with host soybean, non-host maize seed exudates could significantly inhibited Phytophthora sojae mycelial growth, formation and germination of oospores, germination of cysts, which indicated that the seed exudates was the critical factor to host selectivity of Phytophthora sojae and the maize seed exudates was closely related to its non-host resistance.