Abstract Co-cultivation is one of the significant ways to improve the efficacy of biocontrol agents. In the present study, the role of Vel1 on the sporulation, secondary metabolism, mycoparasitism and disease control of Trichoderma atroviride and its influence on B. amyloliquefaciens macrolactin and difficidin gene expressions during co-cultivation have been investigated through the knockout and overexpression of Vel1 gene. Under nutrient stress conditions the T. atroviride Vel1 knockout (T23ΔVel1) exhibited early chlamydospore differentiation, while wild type and over expression strains formed more chlamydospores under nutrient-rich conditions. The differential expression of genes related to sporulation, secondary metabolism, mycoparasitism, and disease control was upregulated by the Vel1 over-expression (T23OVel1), and co-cultivations (T23 + BA and T23OVel1 + BA). The expression of these genes was impaired by the deletion of Vel1 gene and co-culture of B. amyloliquefaciens and T23ΔVel1 strains. Interestingly, macrolactin and difficidin genes of B. amyloliquefaciens were downregulated during co-cultivation with T23OVel1 and upregulated during co-cultivation with T23ΔVel1 strains. The mycoparasitism, plant growth and bio-control activity of T23 + BA and T23OVel1 + BA were superior than other treatments. The T23ΔVel1 showed reduced activity of mycoparasitism, plant growth and biocontrol, but it was increased by the co-culture (T23ΔVel1 + BA) due to the enhanced activity of B. amyloliquefaciens. The results infer that Vel1 of T. atroviride is involved in sporulation, mycoparasitism, disease control and secondary metabolite production. Further, it confirmed that Vel1 downregulates macrolactin and difficidin gene expression of B. amyloliquefaciens and thereby it regulates the compatibility between the T. atroviride and B. amyloliquefaciens to control the wheat root rot disease caused by Fusarium graminearum.

中文翻译：

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Vel1 在与解淀粉芽孢杆菌共培养期间调节木霉属 atroviride 的生长，对控制小麦根腐病至关重要

摘要 共培养是提高生防剂药效的重要途径之一。在本研究中，通过 Vel1 基因的敲除和过表达，研究了 Vel1 在木霉属 atroviride 的孢子形成、次生代谢、真菌寄生和疾病控制中的作用及其对共培养过程中解淀粉芽孢杆菌大乳酸菌和艰难梭菌素基因表达的影响. 在营养胁迫条件下，T. atroviride Vel1 敲除 (T23ΔVel1) 表现出早期厚壁孢子分化，而野生型和过表达菌株在营养丰富的条件下形成更多厚壁孢子。与孢子形成、次级代谢、真菌寄生和疾病控制相关的基因的差异表达被 Vel1 过表达（T23OVel1）上调，和共培养（T23 + BA 和 T23OVel1 + BA）。这些基因的表达因 Vel1 基因的缺失和解淀粉芽孢杆菌和 T23ΔVel1 菌株的共培养而受损。有趣的是，解淀粉芽孢杆菌的大环内乳素和艰难梭菌素基因在与 T23OVel1 共培养期间下调，而在与 T23ΔVel1 菌株共培养期间上调。T23+BA和T23OVel1+BA的真菌寄生、植物生长和生防活性优于其他处理。T23ΔVel1 显示出对真菌寄生、植物生长和生物防治的活性降低，但由于解淀粉芽孢杆菌的活性增强，共培养 (T23ΔVel1 + BA) 增加了它。结果推断 T. atroviride 的 Vel1 参与孢子形成、真菌寄生、疾病控制和次级代谢产物的产生。更多，