Effect of Culture Filtrate of Sinorhizobium Frediisneb183 on the Activity and Behavior of Soybean Cyst Nematode (Heterodera Glycines Ichinohe, 1952)

Rhizobium species and the soybean cyst nematode (SCN, Heterodera glycines) are attracted by the root exudates of soybean and colonize its roots. There is complicated relationship between the soybean, Rhizobium species, and SCN. This study intended to discover the effect of Sinorhizobium fredii Sneb183 culture filtrate on SCN second-stage larvae (J2), egg hatching and J2 chemotaxis. The mortality of J2 treated with S. fredii Sneb183 culture filtrate increased with the exposure duration. Additionally, S. fredii Sneb183 culture filtrate reduced egg hatching within cysts, neutralized the positive effect of a susceptible soybean cultivar root exudate on hatching, and postponed the peak of hatching, thereby revealing other mechanisms for reducing nematode infection and J2 numbers. Heterodera glycines J2 were repelled by the culture supernatant of S. fredii Sneb183, the movement of J2 towards the susceptible cultivar root exudate and soybean roots was disrupted by a mixture of susceptible cultivar root exudate with S. fredii Sneb183 culture filtrate or by dipping the root into culture filtrate. These results indicate that S. fredii Sneb183 may be a potential economic, eco-friendly and effective biocontrol microorganism against SCN.