Studies On Interactions Between Rhizobium, AMF And Ricebean (Vigna Umbellate L.) And Safety Of Releasing Marked Rhizobium To Surroundings

Three Rhizobium spp., Rhizobium sp. CYY3302, Rhizobium sp. HCY9101, Rhizobium sp. JMC1402, which isolated from nodules on ricebean (Vigna umbellate L.) were co-inoculated with Arbuscular Mycorrhizal Fungi(AMF) to ricebean. An alternative planting of inoculated ricebean and corn in field plots were carried out. Counting the nodulation rate, AMF infectivity and the yields of different treatments, the results showed that the nodulation rate of inoculated ricebean was 52% to 134% higher than that of non-inoculated treatment. The AMF infectivity of ricebean and corn increased by 43.1% to 80% and 46.8% to 97.6% respectively. A 54% to 67% increment in ricebean yields and 2.4% to 19.5% in corn yields were also observed.Some studies on colonization of Rhizobium sp. JMC1402P(marked with gfp-gusA gene) showed that how well the rhizobium colonized in the root surface was effected by surroundings . In the cuvette, the root tip of ricebean attracted the rhizobium strongly in early time after inodulation. In the sterilized soil, JMC1402P colonized the root tip less than the whole surface of the root. In the unsterilized soil, the colonization of JMC1402P was affected by the physical and chemical factors of soil, and the aboriginal microbe would compete with it.The safety of releasing JMC1402P to the surrounding was tested, the design was as follows: mixing JMC1402P and R. huakuii JS5A16L(marked with luxAB gene), JMC1402P and Pseudomonas fluorescens Pf.X16L2(marked with luxAB gene) in filterable membrane, sterilized soil and unsterilized soil. No GFP(green fluorescent protein encoded by gfp gene) and luminous clone (with X-GlucA )have been found both in JS5A16L and Pf.X16L2 . The results indicated that JMC1402P was safe when released to the soil.