解淀粉芽胞杆菌菌株HRH317对感染串珠镰孢菌玉米幼苗伏马毒素B1含量及相关防御酶活性的影响

为探讨解淀粉芽胞杆菌Bacillus amyloliquefaciens菌株HRH317对感染串珠镰孢菌Fusarium moniliforme玉米幼苗产生伏马毒素B_1(FB_1)的影响,采用牛津杯法测定菌株HRH317对串珠镰孢菌的抑制活性,并通过浸种处理进行盆栽试验,应用高效液相色谱技术对生长至3叶期后不同时间玉米幼苗叶片中FB_1含量进行测定,同时于室内测定玉米幼苗叶片防御酶超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、苯丙氨酸解氨酶(PAL)和过氧化物酶(POD)的活性。结果表明:解淀粉芽胞杆菌菌株HRH317能明显抑制串珠镰孢菌生长,抑菌圈直径平均可达33.31 mm;玉米幼苗生长至3叶期后1～6 d,菌株HRH317能有效抑制玉米植株体内FB_1含量,经串珠镰孢菌分生孢子悬浮液与菌株HRH317菌悬液1∶1混合液处理玉米种子后,对幼苗中FB_1的抑制率为59.20%～75.70%;而玉米种子先接种菌株HRH317菌悬液后接种串珠镰孢菌分生孢子悬浮液处理对幼苗中FB_1的抑制率为76.77%～88.10%。且这2种处理中幼苗叶片的SOD、CAT、PAL和POD活性均较对照有不同程度提高,其峰值是对照的1.24～5.45倍。表明解淀粉芽胞杆菌菌株HRH317可通过抑制FB_1产生来降低串珠镰孢菌对玉米幼苗的侵害,同时能诱导玉米植株体内防御酶活性的表达而增强其系统抗性,在防治玉米穗腐病方面具有潜在的应用价值。

The impact of Bacillus amyloliquefaciens strain HRH317 on fumonisin B1 content in maize seedlings infected with Fusarium moniliforme and defense-related enzymatic activities

In order to analyze the impact of Bacillus amyloliquefaciens strain HRH317 on fumonisin B₁ (FB₁) produced in maize seedlings infected by Fusarium moniliforme, the inhibitory activity of strain HRH317 was detected by using the Oxford plate assay system. The pot experiments were conducted through maize seed inoculation, and high-performance liquid chromatography (HPLC) was used to determine the content of FB₁ during different growth periods after trefoil stage of maize seedlings. The activities of defense enzymes including superoxide dismutase (SOD), catalase (CAT), phenylalanine ammomialyase (PAL), peroxidase (POD) were measured during different growth periods after trefoil stage. The results showed that B. amyloliquefaciens strain HRH317 could obviously inhibit the growth of F. moniliforme and resulted in inhibition zones on PDA medium, with a diameter of 33.31 mm; and the strain HRH317 showed great promise for inhibiting the production of FB₁ within one to six days after trefoil stage. The inhibition ratio of FB₁ in maize seedlings reached 59.20%-75.70% by seed co-inoculations with strain HRH317 and F. moniliforme (1:1 mixed suspension); the inhibition ratio of FB₁ in maize seedlings reached 76.77%-88.10% by seed treatment with strain HRH317''s cell suspensions first and then being submerged in F. moniliforme''s conidial suspension. The enzyme activities of SOD, CAT, PAL and POD in the leaves of maize seedlings under the above two different treatments were increased to different degrees as compared to the control, with a peak value of 1.24-5.45 folds of the control. These results indicated that B. amyloliquefaciens strain HRH317 could weaken the infection of F. moniliforme in maize seedlings through inhibiting FB₁ production; meanwhile, the strain HRH317 could induce the expression of defense enzymes in maize plants and enhance the systemic resistance of maize plants, and thus has the potential for preventing ear rot of maize.