草莓炭疽病生防菌株的筛选、鉴定及其防治效果

Screening, identification and control effect of biocontrol bacterial strains against strawberry anthracnose

中文关键词:草莓炭疽病  胶孢炭疽菌  孔雀石刺链霉菌  转录组  生物防治

keywords:strawberry anthracnose  Colletotrichum gloeosporioides  Streptomyces malachitospinus  transcriptome  biological control

中文摘要:为获得对草莓炭疽病具有生防潜力的菌株，选取分离自青海高原土壤的11株放线菌菌株，通过平板对峙法比较不同菌株对炭疽病病原菌的抑菌圈大小，对筛选出的优良拮抗菌株进行形态特征分析和分子生物学鉴定，利用盆栽试验验证其对草莓炭疽病的防治效果并通过对盆栽草莓叶片进行转录组学分析来探究其生防机制。结果表明：供试的11株放线菌中菌株8#的抑菌效果最强，抑菌圈直径达29.60 mm。经形态学特征及16S rRNA基因系统发育分析鉴定其为孔雀石刺链霉菌Streptomyces malachitospinus。盆栽试验结果表明，菌株8#处理下的草莓病叶率、病叶柄率和干柄数较对照组分别降低了39.52%、42.27%和82.19%，同时病斑面积显著降低了66.40%。此外，菌株8#显著促进草莓根系生长，根长、根干重和鲜重分别增加了17.57%、41.06%和81.44%。转录组学分析表明，菌株8#处理后的草莓叶片中共鉴定出2 728个差异表达基因，KEGG信号通路富集结果表明在31个信号通路中显著富集，包括苯丙烷类生物合成和植物激素信号传导等相关通路，说明菌株8#可通过上述信号通路在应答机制中发挥作用从而增强草莓的抗病性。表明菌株8#对草莓根系生长有促进作用且对草莓炭疽病有良好的防治效果，具有良好的应用潜力。

Abstract:To obtain bacterial strains with potential of biocontrol against strawberry anthracnose, 11 actinomycete strains isolated from the soil of Qinghai Plateau were selected. The antagonistic circle size of different strains against the pathogen of strawberry anthracnose was compared by plate confrontation method. The morphological characteristics analysis and molecular biological identification of the screened excellent antagonistic strains were carried out. Pot experiment was used to verify its control effect on strawberry anthracnose and the transcriptome of potted strawberry leaves was used to explore its biocontrol mechanism. The results showed that the strain 8# had the strongest antibacterial effect among the 11 tested actinomycetes, and the diameter of the antagonistic circle was 29.60 mm. This strain was identified as Streptomyces malachitospinus through morphological examination and 16S rRNA gene phylogenetic analysis. The results of pot experiment showed that the diseased leaf rate, diseased petiole rate and dry stalk number of strawberry treated with strain 8# were reduced by 39.52%, 42.27% and 82.19%, respectively, compared with the control group, and the lesion area was significantly reduced by 66.40%. In addition, strain 8# significantly promoted the root growth of seedlings, and the length, dry weight and fresh weight of root increased by 17.57%, 41.06% and 81.44%, respectively. Transcriptome analysis revealed that 2 728 differentially expressed genes were identified in strawberry leaves treated with strain 8#. The KEGG signaling pathway analysis indicated significant enrichment in 31 pathways, including phenylpropanoid biosynthesis and plant hormone signal transduction and other related pathways, indicating that strain 8# could play a role in the response through the above signaling pathways to enhance the disease resistance of strawberry. This study showed that the strain 8# could promote the growth of strawberry roots and has obvious control effect on strawberry anthracnose, possessing important application potential.