【目的】通过敲除生防菌Act12铁载体合成酶Ser基因,研究该铁载体在植物防病促生中的作用。【方法】以自杀型质粒p KC1132作为基本载体,两侧为Ser基因上下游片段作为同源交换臂,两个同源臂之间为卡那霉素抗性基因,构建重组质粒p CT12;借助接合转移技术,将该质粒导入Act12,筛选突变株并进行PCR验证;研究Ser基因缺失突变体和野生型菌株Act12在生长速率、铁载体产量、甜瓜种子促生、抗苹果轮纹病菌(Macrophoma kawatsukai)等方面的差异。【结果】经PCR验证及测序均证实Ser基因缺失突变体构建成功。Ser基因突变后,铁载体合成量明显减少,抑制甜瓜种子的萌发及生长,对苹果轮纹病菌拮抗作用降低。【结论】生防菌Act12 Ser合成酶基因参与控制合成的铁载体在对甜瓜种子促生作用和拮抗苹果轮纹病菌中发挥一定作用,为进一步研究Act12防病促生机制奠定基础。 【Objective】 The purpose of this study was to investigate the role of iron transporter in the plant disease prevention and growth enhancement by knocking out the Act12 gene of Act12 iron-containing synthase. 【Method】 The suicide plasmid p KC1132 was used as the basic vector, the upstream and downstream fragments of Ser gene were used as homologous exchange arms on both sides, and the kanamycin resistance gene was located between two homologous arms to construct recombinant plasmid p CT12. Ligation and transfer technology, the plasmid was introduced into Act12, and the mutants were screened and verified by PCR. The effects of Ser gene deletion mutant and wild type strain Act12 on the growth rate, iron vector production, melon seed production, Macrophoma kawatsukai ) And other differences. 【Result】 The results of PCR validation and sequencing proved that the deletion of Ser gene was successful. After the mutation of Ser gene, the synthesis of iron carrier decreased obviously, inhibited the germination and growth of melon seeds, and decreased the antagonism of apple rotten pathogen. 【Conclusion】 Biocontrol agents Act12 Ser synthase gene involved in the control of synthesis of iron carrier plays a role in promoting the growth of melon seeds and antagonizing the pathogen of apple whetstone, which lays the foundation for further study on the mechanism of promoting growth and development of Act12.