Department of Plant Protection, Faculty of Agriculture, University of Kurdistan, Sanandaj, Iran.
Department of Plant Protection, Faculty of Agriculture, University of Kurdistan, Sanandaj, Iran.
Int J Food Microbiol. 2019 Oct 16;307:108276. doi: 10.1016/j.ijfoodmicro.2019.108276. Epub 2019 Jul 29.
A nonpathogenic endophytic bacterial isolate, recovered from Fragaria × ananassa stolon, and its antifungal activity against Colletotrichum nymphaeae was evaluated under in vitro, in vivo, and greenhouse conditions. Bacterial isolate was identified as Staphylococcus sciuri MarR44 (Strain ID: WDCM 891 = CCSM-B 00640) using phenotypic and biochemical properties and molecular phylogenetic analysis of the 16S rDNA gene sequences. The living cells of strain MarR44 inhibited mycelial growth of C. nymphaeae (52.46%) using dual-culture method. The volatile compounds (VOCs) produced by MarR44 inhibited mycelial growth and conidial germination of C. nymphaeae by 34.52% and 82.81%, respectively. However, inhibition percentage of mycelial growth of pathogen by culture filtrates of the strain MarR44 was lower (23.07%) than that for the two dual culture and volatile compounds assay tests. Moreover, the cell-free-culture filtrates of this strain reduced the biomass and conidial germination of pathogen by 91.89% and 41.10%, respectively. Also, the strain MarR44 was capable of producing protease, chitinase, HCN, siderophore, IAA, gibberellin, and biofilm. The living cells and volatile compounds of the strain MarR44 reduced anthracnose disease at post-harvest on fruit by 52.45% and 72.17%, respectively. Furthermore, disease severity of strawberry anthracnose was reduced using drenching soil and inoculated plants methods by 77.77 and 72.22%, respectively, 60 days after inoculation. The VOCs released by strain MarR44 were analyzed by Gas chromatography-mass spectroscopy (GC-MS). Out of 24 identified VOCs, Mesityl oxide (81.436%), Acetic acid, 2-methylpropyl ester (3.442%), 4-Methyldecane (1.837%), 4-Penten-2-one,4-methyl- (1.739%), Toluene (1.248%), and o-Xylene (1.24%) were the major components. The mode of action of S. sciuri MarR44 on the C. nymphaeae was through the production of antifungal volatile compounds (Antibiosis), which inhibited mycelial growth and conidial germination of pathogen in vitro and fruit decay development in vivo. To the best of our knowledge, this is the first report of S. sciuri having antifungal activity against causal agent strawberry anthracnose. These results indicated that the VOCs of S. sciuri strain MarR44 are promising biofumigant for management of strawberry anthracnose.
从草莓匍匐茎中分离出一种非致病性内生细菌，并评估其对毛叶花莲炭疽病菌的抑菌活性，实验分别在体外、体内和温室条件下进行。采用表型和生化特性以及 16S rDNA 基因序列的分子系统发育分析，将细菌分离株鉴定为松鼠葡萄球菌 MarR44（菌株 ID：WDCM 891=CCSM-B 00640）。使用双重培养法，菌株 MarR44 的活菌抑制了毛叶花莲炭疽病菌的菌丝生长（52.46%）。MarR44 产生的挥发性化合物（VOCs）分别抑制了毛叶花莲炭疽病菌的菌丝生长和分生孢子萌发 34.52%和 82.81%。然而，菌株 MarR44 的培养滤液对病原体菌丝生长的抑制率（23.07%）低于双重培养和挥发性化合物测定的两种测试。此外，该菌株的无细胞培养滤液使病原体的生物量和分生孢子萌发分别减少了 91.89%和 41.10%。此外，菌株 MarR44 能够产生蛋白酶、几丁质酶、HCN、铁载体、IAA、赤霉素和生物膜。MarR44 的活菌和挥发性化合物分别将果实采后炭疽病的发病率降低了 52.45%和 72.17%。此外，通过灌根和接种植株的方法，在接种后 60 天，草莓炭疽病的严重程度分别降低了 77.77%和 72.22%。通过气相色谱-质谱联用仪（GC-MS）分析了 MarR44 菌株释放的 VOCs。在鉴定出的 24 种 VOC 中，主要成分包括均三甲苯氧化物（81.436%）、2-甲基丙基乙酸酯（3.442%）、4-甲基癸烷（1.837%）、4-戊烯-2-酮，4-甲基-（1.739%）、甲苯（1.248%）和对二甲苯（1.24%）。松鼠葡萄球菌 MarR44 对毛叶花莲炭疽病菌的作用方式是通过产生抑菌挥发性化合物（抗生作用），从而抑制了病原体在体外的菌丝生长和分生孢子萌发以及体内果实腐烂的发展。据我们所知，这是首次报道松鼠葡萄球菌对草莓炭疽病病原菌具有抑菌活性。这些结果表明，松鼠葡萄球菌 MarR44 菌株的 VOC 有望成为防治草莓炭疽病的生物熏蒸剂。
