The rhizosphere regulation mechanism and use of root exudates to inhibit continuous monocropping barrier by nematode disease

Long term continuous monocropping easily results in the continuous monocropping barrier (replant disease) to most crops. The continuous monocropping barrier phenomenon, such as Xinjiang cotton, Heilongjiang soybean, Henan peanut, Shandong horticultural vegetables and Guangdong and Guangxi bananas caused by traditional farming patterns and farmer habit happened all over China. Continuous monocropping barrier was dominated by economic crops in each province and classified into five levels according to the agricultural area, among which three provinces in North China and Heilongjiang Province in Northeast China had the highest level. Based on the minimum and normal yields comparison of bananas, soybeans (economic crops), cucumbers (horticultural vegetables) and pseudo-ginseng (traditional Chinese medicine) in continuous cropping years, the continuous monocropping barrier occurrence regularity was drawn as parabola. The accumulation of single root exudate of replant crops could significantly not only decrease soil microbial diversity but also promote pathogen and nematode damage and soil salinization which led to crop development and yield losses. More importantly, the plant parasitic nematode disease was a global pest that affected many crops, particularly in greenhouse. The interaction between plants and nematodes, was typically regulated by exudate compounds released from different roots in rhizospheres during evolution process. For the nematode diseases induced by root exudates-nematodes interaction, the rhizosphere regulation was put forward on the biological mechanisms of susceptible crops and resistant/non-host plants root exudates to nematode hatching and infection. Regulate Mi-16D10, Mi-flp-18 gene of root knot nematode and Hg-rbp-2 gene of cyst nematode expression in root rhizosphere by using root exudates of resistant/non-host plants to control the hatching, infection and chemistry of nematode in J2 period. These results enhanced our understanding of the regulatory mechanism of bioactive compounds from against plant parasitic nematodes. In the future, biofunctional fertilizers will be deployed on the basis of screening and identification of the resistant/non-host plant specific root exudates regulation on nematode infection. Novel ecofriendly biofunctional fertilizers directionally regulate plant rhizosphere biological process and promote sustainable production in greenhouse environments based on bioactive compounds from plant would be a hot research topic. This paper will provide a theoretical basis for further study of root exudate-nematode interaction and overcoming continuous monocropping barrier, so as to promote soil health and high-yield and high-efficiency of crops. It has important theoretical and practical guiding significance for achieving green agriculture and sustainable development.