Research And Control Effect On Novel Microbial Complex Seed-Coating Agent SN102 Of Soybean

Based on the theory of Microbial diversity and induced resistance,a new novel microbial complex seed-coating agent SN102 against both soybean cyst nematode and root rot diseases was developed.And its efficacy was proved in soybean fields in order to solve the problem of multiple infection of soybean root diseases.SN102 was made by 4 biocontrol strains Bacillus megaterium Sneb 482,Bacillus simplex Sneb 545,Sinorhizobium fredii Sneb 183 and Penicillium chrysogenum Snef 805.They were mixed in proportion and additives were added into the mixed fermentation broth.It was tested at Kangping of Shenyang in Liaoning province and Daqing in Heilongjiang province in 2015 and 2016.The detail results were as follows:1.The development of biological seed coating agent SN102.The biocontrol strains which have good efficacy to soybean cyst nematode(SCN)and root rot disease were screened and mixed in proportion by plate confrontation experiments,germination tests after seeds coating by fermentation liquids,testing the fatality rate of different mixed fermentation liquids on nematode and pot experiments.The proportion of the best mixed fermentation liquids was Sneb 545:Sneb 482:Sneb 183:Snef 805=(3×109):109:109:(0.5×108).The results showed that the final mixed liquid in proportion had good efficacy against SCN and root rot disease and it could promote the germination and seedling growth of soybean.2.Efficacy of SN102 against soybean root diseases of seedling stage.The inhibition of SN102 on SCN were 46.36%in 2015 and 39.35%in 2016 at Kangping,while 28.55%in 2015 and 29.33%in 2016 at Daqing.The average inhibition for two years were 37.80%and 28.95%at Kangping and Daqing,respectively.The inhibition of SN102 on root rot disease were 18.15%in 2015 and 14.47%in 2016 at Kangping,while 17.09%in 2015 and 41.49%in 2016 at Daqing.The inhibition at average for two years were 16.31%and 29.57%at Kangping and Daqing,respectively.It indicated that SN102 had efficacy to SCN and root rot disease.3.Promotion of SN102 on soybean growth and production.The results of two places showed that SN102 could promote the growth of soybean in seedling stage compared with CK.SN102 could promote main root length significantly at two places in two years.SN102 could improve plant height and root fresh weight observably at Daqing in 2016.And it had evidently promotion of shoot fresh weight at two places in 2016.As to soybean theoretical production,there were,respectively,21.10%and 12.36%promotion coated by SN102.As well as the measured production in yield of 2016,there was 16.26%promotion at Kangping.At Daqing,although there was waterlogging caused by excessive rain,SN102 had a good seedling emergence to defense the disaster,and also had 72.73%promotion in yield.4.Effect of SN102 on the expression of PR genes from soybean roots.PR genes including PR1,PR2,PR3a,PR3b and PR9 were selected to be tested by QPCR.The results showed that the expression of PR1,PR2,PR3b and PR9 had increased compared with CK after inoculated by SCN J2.And the main increasing time of these genes was different.It may indicate that coating by SN102 probably induced the expression of PR proteins such as chitinase,?-1,3-aglucanase and peroxidase which may join in the process of resisting the infection of SCN.SN102 could not only resist the infection of SCN,but also inhibit root rot disease of soybean at two test locations during two years.In the meantime,SN102 could promote the growth and production of soybean.The results provide certain theoretical value and practical significance for soybean diseases control in Northeast China.