The Control Mechanism Of Sinorhizobium Fredii Sneb183Against Soybean Cyst Nematode

The action mechanisms of Sinorhizobium fredii Sneb183against soybean cyst nematode were researched in this paper systematically, and the interaction relationship was revealed among Snebl83, soybean cyst nematodes (SCN) and soybeans. Through the effect of Sneb183on nematode activity, mortality rate, hatching rate, respiration and so on, the action mode of Sneb183on nematode was understood. The ability of Sneb183to systemically repress SCN was tested, and study revealed Sneb去83induced systemic resistance in soybean and also could inhibit nematode development in soybean root. The differential proteome was used to reveal the change of proteome in the soybean root under nematode infection condition when inoculated with Sneb183; through the differential proteome we could understand the relationship among these three and the mechanism of induced systemic resistance in soybean by Sneb183. The main results were as follows:1. To make clear the effect mode of Snebl83on soybean cyst nematode juvenile two (J2). When nematode were treated with Sneb183fermentation liquid, action capability was inhibited significantly, and72h mortality rate was84.3%. The hatching rate reduced62.4%when the egg treated with fermentation liquid. Meanwhile Sneb183could inhibit J2breathing and cause fluid leakage, and ultimately suppress nematode activity or even death.2. Verified the Sneb183inhibit soybean cyst nematode on the soybean root through greenhouse and field experiments. In greenhouse experiment, the inhibition rate of J2and cyst in soybean root treated with Sneb183was40.13%and37.8%respectively. In field experiment, the inhibition rate of cyst was46.2%after inoculation of Sneb183. Meanwhile, Sneb183also showed growth-promoting effect on soybean seedling growth. In soybean maturity period, the numbers of pods and beans of soybeans treated with Sneb183were both increased significantly, which were1.34and1.34times respectively compared with control treatment.3. Verify the induced systemic resistance of soybean by Sneb183. Through split-root method, we proved Sneb183could induce systemic resistance of soybean, thereby inhibit J2infection, the inhibit rate was38.8%. Frozen technique was used to observe changes of plant root organization, and observed that Sneb183could induce epidermal thickening, and increase pericycle dencity. The structure of root changed more compact and thus resisted nematode infestation and limited development. By measuring the disease related enzymatic activity, showed that Sneb183could stimulate the resistance related enzyme activity, which also determined Sneb183could induce systemic resistance.4. Proved Sneb183could inhibit nematode development in soybean root, and made nematode juvenile growing slowly. The root exudates of soybean inoculated with Sneb183was toxic to nematode, this improved that Snebl83could change the root exudates of soybean, and had lethal effect on J2. By measuring the root exudates effects of different distances from the root nodule to nematode, and the number of J2infestation in different parts of the root system, there was no significant difference between the Sneb183treatment and control, thus improved Sneb183induced nematode suppression effect of soybean is a system resistance.5. iTRAQ technology was used to test the differential proteome in soybean root when inoculated with Sneb183. The Sneb183treatment and control treatment were both under stress of nematode inoculation. By this way, revealed the effect of Sneb183induced soybean against nematode at proteomic perspective. A total of456differential proteome were identified, in which244proteins were increased and212proteins were reduced. These proteins are involved in the biological process, molecular function, cellular component and so on.6. On the basis of differential proteome result, BLAST2GO was use to note protein function, and then used KEGG bioinformatics method to identify the pathway which these proteins involved in, and obtain the biological map. In these differential proteome,118kinds of metabolic pathways was identified, including calcium signaling pathway, flavonoid biosynthesis, pentose phosphate pathway, glutathione metabolism and so on. These pathways were all involved in energy metabolism and systemic resistance of plant, so the soybean resistance to nematode was increased by Sneb183.