秸秆降解过程中拮抗链霉菌对禾谷镰刀菌消长动态的影响

由禾谷镰刀菌(Fusarium graminearum)引起的小麦赤霉病是导致小麦产量和品质降低的主要因素，其在田间生长的基质主要为秸秆。基于各种拮抗菌的生物防治是控制小麦赤霉病的主要措施之一，但秸秆降解过程中拮抗菌的拮抗效应是否与平板对峙获取的拮抗效应一致尚不清楚。本研究首先通过平板对峙试验，筛选出对禾谷镰刀菌CGMCC3.4598有潜在拮抗作用的3株菌：吸水链霉菌ACCC41648 (Streptomyces hygroscopicus)、吸水链霉菌井冈变种ACCC40051 (S. hygroscopicus var. jingganggensis)和娄彻氏链霉菌ACCC41594(S.rochei)，其抑菌带平均宽度依次为2.67、1.67和1.12mm。基于室内70d培育试验，发现秸秆降解7、42和70 d后，吸水链霉菌ACCC41648及其井冈变种ACCC40051未表现抑制秸秆中禾谷镰刀菌生长的效应，而娄彻氏链霉菌ACCC41594在秸秆降解7 d和42 d后显著降低禾谷镰刀菌丰度分别达30.91%和69.28%。与对照相比，娄彻氏链霉菌ACCC41594显著促进秸秆降解...

Dynamic Analysis on Antagonistic Streptomyces Against Growth and Decline of Fusarium graminearum during Straw Degradation

Fusarium head blight (FHB) caused by Fusarium graminearum which utilizes straw as main growth media in field is the main factor leading to reduction of wheat yield and quality. Biological control with various antagonistic organisms is one of the most effective methods to prevent and control FHB, however, it is not clear whether the antagonistic effect of antagonistic organisms in straw degradation process is in accordance with that in plate confrontation experiment. In this study, three kinds of strains with potential antagonistic effects on F. graminearum CGMCC3.4598 were primarily screened out through plate confrontation culture, they were Streptomyces hygroscopicus ACCC41648, S. hygroscopicus var. jingganggensis ACCC40051, and S. rochei ACCC41594, and the average width of their antifungal bands were 2.67 mm, 1.67 mm, and 1.12 mm, respectively. Next, based on indoor 70-day culture experiment, we found that after 7, 42, and 70 days of straw degradation, S. hygroscopicus ACCC41648 and its variant ACCC40051 did not show any antagonistic effects on the growth of F. graminearum in residual straw, while S. rochei ACCC41594 respectively reduced the abundance of F. graminearum in residual straw by 30.91% and 69.28% after 7 and 42 days of straw degradation. Compared with the control (no antagonistic organisms were added), S. rochei ACCC41594 significantly promoted straw degradation, increased cumulative emission amount of CO2-C, and reduced the size of easily mineralizable carbon in straw. Further correlation analysis found that the abundance of F. graminearum in residual straw had significant negative correlation with total potassium content of straw at 7 d (P<0.01), positive correlation with easily mineralizable carbon content of straw at 42 d (P<0.05), and positive correlation with total nitrogen content of straw and negative correlation with C/N of straw at 70 d (P<0.01). The above results indicate that the antagonistic strains screened from the plate confrontation may not always reappear their antagonistic effects during straw degradation. The results further indicate that the inhibition effect of S. rochei ACCC41594 on the growth of F. graminearum CGMCC3.4598 during straw degradation may be through its direct antagonism, or through its indirect effect that changing residual straw properties when it promoted straw degradation.