生物拌种剂防治大豆根腐病效果和机制

Efficacy and Mechanism of Biological Seed Coating Agent Against Soybean Root Rot Disease Caused by Fusarium oxysporum f.sp.vedolens

大豆根腐病是黑龙江大豆产区的主要根部病害,其病原菌主要为Fusarium.oxysporumf.sp.vedolens。枯草芽孢杆菌B29对大豆根腐病菌具有较强的抑制作用,将枯草芽孢杆菌B29菌液和一些营养因子等复配成生物拌种剂,通过室内抑菌试验、田间小区试验和PCR-DGGE技术对生物拌种剂对大豆根腐病菌F.oxysporumf.sp.vedolens的抑菌活性和生防机理进行了研究。结果表明:生物拌种剂对大豆根腐病菌孢子萌发和菌丝生长具有较强的抑制作用,抑制率与拌种剂浓度呈正相关,原液和10倍稀释液抑制率均达93%以上,1000倍稀释液的抑制率为75%;拌种剂处理大豆后大豆苗期体内与抗性反应相关的苯丙氨酸解氨酶(PAL)、过氧化物酶(POD)和多酚氧化酶(PPO)活性明显增强;拌种剂中的生防菌能够在大豆根际土壤中定殖,对根际土壤微生物种群数量未造成影响。田间小区试验显示生物拌种剂对大豆根腐病的苗期防效达60%以上。

The soybean root rot is a kind of main fungal disease in Heilongjiang province. It was mainly caused by F. oxysporum f. sp. Vedolens. Bacillus subtilis B29 could inhibit the growth of F. oxysporum f. sp. vedolens. In this study,we researched the efficacy and mechanism of biological seed coating agent against soybean root rot disease caused by F. oxysporum f. sp. vedoleus by the method of mycelia growth, dual culture, spore germination, microscope inspection, field trail and PCR- DGGE. The results indicated that biological seed coating agent could inhibit the growth of F. oxysporum f. sp. vedolens, distort the mycelia and spore and enhance the enzyme activities of POD, PPO and PAL in soybean root. The biocontrol bacteria could reside in rhizosphere of soybean and did not effect on the population of soil microbes. The efficacy of seed coating agent against soybean root rot disease was over 60% in field trail.