Abstract: Corn stalk rot is a soil borne disease commonly coourring in corn production areas of the world, and it is also one of the main diseases in corn production areas of China. In order to screen suitable antagonistic bacteria of corn stalk rot pathogen and study the effect of seed coating agent on corn growth, the antagonistic strains of corn stalk rot pathogen were screened by plate confrontation test, and the strains with potential to promote corn seed growth were further screened by measuring two physiological indexes of iron carrier and indoleacetic acid, and the screened strains were used as the activity of microbial seed coating agent. The effects of different proportion of film-forming agent on seed germination, seedling growth and strain activity of maize were studied. In this study, 5 strains of bacteria and 1 strain of Trichoderma were found to inhibit the pathogen of corn stalk rot by plate confrontation test. By further physiological indexes, 6 strains of Bacillus with potential to promote the growth of corn seeds and the ability to produce IAA and iron carriers were obtained. TXM-1 (Bacillus velezensis) and TXM-2 (Bacillus amyloliquefaciens) were selected as the active components of biological seed coating agents based on the functions of bacteria inhibition and the growth promotion. The germinating test of corn seed showed that BSCA-1 and BSCA-2 had the functions of antagonizing pathogen and promoting the growth of corn seedling. Their formulations were as follows: TXM-1 and TXM-2 as active components, sodium alginate and polyvinyl alcohol as film-forming agents, bentonite and benzophenone as additives, respectively. The best mixing ratio of the two film formers was 1∶9, which could not only promote the growth of corn, but also delay the decline rate of the activity of the film formers. The results showed that the biological seed coating agent based on two kinds of Bacillus could not only antagonize the pathogen of corn stalk rot, but also promote the growth of corn seedling, which revealed its potential to replace the chemical seed coating agent in corn planting.

Key words: corn stalk rot, antibacterial activity, promoting effect, film-forming agents, biological seed coating agent

摘要： 玉米茎腐病是世界玉米产区普遍发生的一种土传病害，也是我国玉米产区的主要病害。为了筛选合适的玉米茎腐病病原菌的拮抗菌，并研究其种衣剂对玉米生长的作用，采用平板对峙试验对10株疑似拮抗菌进行筛选，并测定铁载体和吲哚乙酸（IAA）两种生理指标，筛选对玉米种子有促生潜力的菌株，将筛选到的菌株作为微生物种衣剂的活性成分，研究不同比例成膜剂对玉米种子发芽、苗期生长及菌株活力的影响。结果筛选到5株细菌和1株木霉对病原菌有抑制作用，生理指标筛选获得6株对玉米种子有促生潜力的菌株，均具有产铁载体和IAA的能力。综合抑菌和促生两种功能，确定两种芽孢杆菌TXM-1和TXM-2作为生物种衣剂的活性成分。玉米种子发芽试验显示，生物种衣剂BSCA-1和BSCA-2兼具拮抗病原菌和促进玉米苗期生长的功能。生物种衣剂的最佳配方为：分别以TXM-1和TXM-2为活性成分，以海藻酸钠(SA)和聚乙烯醇(PVA)为成膜剂，膨润土和苯甲酸钠为助剂，其中两种成膜剂最佳配比为90%SA+10%PVA，该配方在促进玉米生长的同时，可延缓菌剂活性的下降速率。结果表明，基于两种芽孢杆菌构建的生物种衣剂在拮抗玉米茎腐病病原菌的同时，对玉米苗期生长有促进作用，表明其在玉米种植中具有替代化学种衣剂的潜力。

关键词: 茎腐病, 抑菌, 促生作用, 成膜剂, 生物种衣剂