不同品种小麦与蚕豆间作对蚕豆枯萎病的防治及其机理

Faba bean fusarium wilt( Fusarium oxysporum) control and its mechanism in different wheat varieties and faba bean intercropping system

通过田间小区试验和水培试验,研究了3个品种小麦(云麦42、云麦47和绵阳29)与蚕豆间作对蚕豆地上部生物量、枯萎病发生、根际微生物代谢功能多样性和枯萎病病原菌尖孢镰刀菌数量的影响,分析了3个不同小麦品种低分子量根系分泌物组分(糖、氨基酸和有机酸)的差异.结果表明:云麦42与蚕豆间作(YM42/B)和云麦47与蚕豆间作(YM47/B)使蚕豆地上部生物量分别增加16.6%和13.4%,使蚕豆枯萎病病情指数分别降低47.6%和23.3%,绵阳29与蚕豆间作(MY29/B)对蚕豆地上部生物量和枯萎病病情指数均无显著影响.与单作蚕豆相比,YM42/B和YM47/B处理均显著提高了蚕豆根际微生物的平均颜色变化率(AWCD)及对碳源的总利用强度和Biolog ECO板中各种碳源的利用,明显改变了蚕豆根际微生物群落结构,并显著降低了蚕豆根际的尖孢镰刀菌数量;MY29/B处理对AWCD值、碳源总利用强度和Biolog ECO板中各种碳源的利用及蚕豆根际尖孢镰刀菌数量均无显著影响,也未明显改变蚕豆根际的微生物群落结构.3个小麦品种根系分泌物中可溶性糖、游离氨基酸总量和有机酸总量均表现为MY29>YM47>YM42.MY29根系分泌物中丝氨酸、谷氨酸、甘氨酸、缬氨酸、蛋氨酸、苯丙氨酸、赖氨酸的含量均显著高于YM42和YM47;精氨酸为YM42、YM47所特有,而亮氨酸为MY29所特有.MY29和YM47根系分泌物中检出酒石酸、苹果酸、柠檬酸、琥珀酸、延胡索酸和顺乌头酸6种有机酸,而YM42根系分泌物中检出洒石酸、苹果酸、柠檬酸和延胡索酸4种有机酸,且MY29和YM47根系分泌物中苹果酸含量显著高于YM42.小麦与蚕豆间作提高了蚕豆根际微生物的活性和碳源利用强度,改变了根际微生物的群落结构,降低了蚕豆根际尖孢镰刀菌的数量,促进了蚕豆生长,抑制了蚕豆枯萎病的发生,但小麦与蚕豆间作控病效果受小麦品种的影响,表明间作系统中非寄主作物根系分泌物的差异是影响间作对土传病害控制的重要因素.

Field experiment and hydroponic culture were conducted to investigate effects of three wheat varieties （Yunmai 42, Yunmai 47 and Mianyang 29 ） and faba bean intercropping on the shoot biomass, disease index of fusarium wilt, functional diversity of microbial community and the amount of Fusarium oxysporum in rhizosphere of faba bean. Contents and components of the soluble sugars, free amino acids and organic acids in the root exudates were also examined. Results showed that, compared with monocropped faba bean, shoot biomass of faba bean significantly increased by 16.6% and 13.4%, disease index of faba bean fusarium wilt significantly decreased by 47.6% and 23.3 % as intercropped with Yunmai 42 and shoot biomass and disease index were found as Yunmai 47, but no significant differences of both intercropped with Mianyang 29. Compared with monocropped faba bean, the average well color development （AWCD value） and total utilization ability of carbon sources of faba bean significantly increased, the amount of Fusarium oxysporum of faba bean rhizosphere significantly decreased, and the microbial community structures of faba bean rhizosphere changed as intercropped with YM42 and YM47, while no significant effects as inter- cropped with MY29. Total contents of soluble sugar, free amino acids and organic acids in root exu- dates were in the trend of MY29〉YM47 〉YM42. Contents of serine, glutamic, glycine, valine, me- thionine, phenylalanine, lysine in root exudates of MY29 were significantly higher than that in YM42 and YM47. The arginine was detected only in the root exudates of YM42 and YM47, and leucine was detected only in the root exudates of MY29. Six organic acids of tartaric acid, malic acid, citric acid, succinic acid, fumaric acid, t-aconitic acid were detected in root exudates of MY29 and YM47, and four organic acids of tartaric acid, malic acid, citric acid, fumaric acid were detected in root exudates of YM42. Malic acid content in root exudates of YM47 and MY29 was sig- nificantly higher than that of YM42. In conclusion, intercropping influenced the microbial activity and substrate utilization of soil microorganisms, altered the microbial community diversity in rhizo- sphere of faba bean, reduced the amount of F. oxysporum and disease index of faba bean fusarium wilt, and promoted faba bean growth. Effects of intercropping on disease control were influenced by the intercropped wheat variety, suggesting that the differences of root exudates of wheat were impor- tant factors that affected soil-borne diseases control in intercropping.