TY - JOUR
T1 - The antifungal action mode of the rice endophyte Streptomyces hygroscopicus OsiSh-2 as a potential biocontrol agent against the rice blast pathogen
AU - Xu, Ting
AU - Cao, Lidan
AU - Zeng, Jiarui
AU - Franco, Christopher M.M.
AU - Yang, Yuanzhu
AU - Hu, Xiaochun
AU - Liu, Ying
AU - Wang, Xiang
AU - Gao, Yan
AU - Bu, Zhigang
AU - Shi, Liming
AU - Zhou, Guoying
AU - Zhou, Qian
AU - Liu, Xuanming
AU - Zhu, Yonghua
PY - 2019/10
Y1 - 2019/10
N2 - Microbial antagonists and their bioactive metabolites provide one of the best alternatives to chemical pesticides to control crop disease for sustainable agriculture and global food security. The rice endophyte Streptomyces hygroscopicus OsiSh-2, with remarkable antagonistic activity towards the rice blast fungus Magnaporthe oryzae, was reported in our previous study. The present study deciphered the possible direct interaction mode of OsiSh-2 against M. oryzae. An in vitro antibiotic assay for OsiSh-2 culture filtrate revealed strong suppression of mycelial growth, conidial germination and appressorial formation of M. oryzae. Meanwhile, severe morphological and internal abnormalities in M. oryzae hyphae were observed under a scanning electron microscope and transmission electron microscope. Foliar treatment of rice seedlings by OsiSh-2 culture filtrate in the greenhouse and in the field showed 23.5% and 28.3% disease reduction, respectively. Correspondingly, OsiSh-2 culture filtrate could induce disorganized chitin deposition in the cell wall and lowered ergosterol content in the cell membrane of M. oryzae. Additionally, cell wall integrity pathway activation, large cell electrolytes release, reactive oxygen species accumulation and tricarboxylic acid cycle-related enzyme activity changes were found in M. oryzae. All these results suggested that the direct antagonistic activity of OsiSh-2 against M. oryzae may be attributed to damaging the integrity of the cell wall and membrane and disrupting mitochondrial function in the pathogen.
AB - Microbial antagonists and their bioactive metabolites provide one of the best alternatives to chemical pesticides to control crop disease for sustainable agriculture and global food security. The rice endophyte Streptomyces hygroscopicus OsiSh-2, with remarkable antagonistic activity towards the rice blast fungus Magnaporthe oryzae, was reported in our previous study. The present study deciphered the possible direct interaction mode of OsiSh-2 against M. oryzae. An in vitro antibiotic assay for OsiSh-2 culture filtrate revealed strong suppression of mycelial growth, conidial germination and appressorial formation of M. oryzae. Meanwhile, severe morphological and internal abnormalities in M. oryzae hyphae were observed under a scanning electron microscope and transmission electron microscope. Foliar treatment of rice seedlings by OsiSh-2 culture filtrate in the greenhouse and in the field showed 23.5% and 28.3% disease reduction, respectively. Correspondingly, OsiSh-2 culture filtrate could induce disorganized chitin deposition in the cell wall and lowered ergosterol content in the cell membrane of M. oryzae. Additionally, cell wall integrity pathway activation, large cell electrolytes release, reactive oxygen species accumulation and tricarboxylic acid cycle-related enzyme activity changes were found in M. oryzae. All these results suggested that the direct antagonistic activity of OsiSh-2 against M. oryzae may be attributed to damaging the integrity of the cell wall and membrane and disrupting mitochondrial function in the pathogen.
KW - Antifungal activity
KW - Endophyte
KW - Magnaporthe oryzae
KW - Mode of action
KW - Streptomyces hygroscopicus OsiSh-2
UR - http://www.scopus.com/inward/record.url?scp=85068188381&partnerID=8YFLogxK
U2 - 10.1016/j.pestbp.2019.06.015
DO - 10.1016/j.pestbp.2019.06.015
M3 - Article
C2 - 31519258
AN - SCOPUS:85068188381
VL - 160
SP - 58
EP - 69
JO - Pesticide Biochemistry and Physiology
JF - Pesticide Biochemistry and Physiology
SN - 0048-3575
ER -