analysis of strawberry metabolic profiling in interaction with bacillus spp. strain dm12 using gas chromatography-mass spectrometry and determination of its antifungal activity

Colletotrichum nymphaeae infects the roots, leaves and fruits of the plant at different developmental stages and is one of the most important diseases of strawberry. the principal problems to strawberry cultivation are fruit rot caused by anthracnose that affect the quality and quantity of production and marketing in the field, and post–harvest. an endophytic bacterial strain, isolated from fragaria × ananassa, and antifungal properties against colletotrichum nymphaeae was assayed under in vitro, in vivo, and greenhouse experiments. bacterial strain was identified as bacillus spp. dm12 (mh161581) using phenotypic, biochemical and molecular phylogenetic analysis of the 16s rdna gene. dm12 strain inhibited mycelial growth of fungal pathogen (64.03%) using dual–culture test. the cell–free culture compounds produced by dm12 prevented mycelial growth and conidial germination of c. nymphaeae by 32.86% and 73.98%, respectively but, inhibition percentage of mycelial growth of pathogen by volatile compounds was less (9.82%). as well as, protease, chitinase, pectinase, siderophore, iaa, gibberellin, and phosphate solubilization tests for this strain were positive. anthracnose disease at post–harvest on fruit suppressed by the strain dm12 (90.87%). also, biocontrol efficacy on strawberry plants by drenching soil and spraying methods were 72.22% and 94.44%, respectively, 60 days after inoculation. pcr amplification represented the presence of genes of surfactin. in addition, metabolite profile of strawberry was changed on presence of bacterial strain that a number of metabolites in control treatment with maximum area percent were acetoglyceride (19.418%), acetic acid, butyl ester (4.734%) and ribitol (4.349%), in treatment inoculated with dm12 strain alone were tetramethyl–2–hexadecen (21.35%), ethylene glycol monoisobutyl ether (18.688%) and myrtenol (8.75%), in treatment inoculated with fungal pathogen alone were acetoglyceride (18.089%) and acetic acid, monoglyceride (17.96%) and in treatment inoculated with c. nymphaeae  and dm12 strain together were tert–butanethiol (36.153%), ethoxy triethyl silane (14.126%), 5–(methylamino)–1,2,3,4–thiatriazole (9.53%) and 2,3–butanediol (7.795%). some of these compounds, such as butanediol, lactose and tetradecane, which were produced in dm12 strain alone and c. nymphaeae and dm12 strain together treatments, have antifungal properties. these results showed that strain dm12 has able to decrease mycelial growth, conidial germination, fruit decay development and disease severity of strawberry anthracnose under in vitro, in vivo and greenhouse conditions. further works are required in order to understanding the interaction of dm12 with the plant and others phytopathogens and its effects on the plant defense system..

analysis of strawberry metabolic profiling in interaction with bacillus spp. strain dm12 using gas chromatography-mass spectrometry and determination of its antifungal activity

colletotrichum nymphaeae infects the roots, leaves and fruits of the plant at different developmental stages and is one of the most important diseases of strawberry. the principal problems to strawberry cultivation are fruit rot caused by anthracnose that affect the quality and quantity of production and marketing in the field, and post–harvest. an endophytic bacterial strain, isolated from fragaria × ananassa, and antifungal properties against colletotrichum nymphaeae was assayed under in vitro, in vivo, and greenhouse experiments. bacterial strain was identified as bacillus spp. dm12 (mh161581) using phenotypic, biochemical and molecular phylogenetic analysis of the 16s rdna gene. dm12 strain inhibited mycelial growth of fungal pathogen (64.03%) using dual–culture test. the cell–free culture compounds produced by dm12 prevented mycelial growth and conidial germination of c. nymphaeae by 32.86% and 73.98%, respectively but, inhibition percentage of mycelial growth of pathogen by volatile compounds was less (9.82%). as well as, protease, chitinase, pectinase, siderophore, iaa, gibberellin, and phosphate solubilization tests for this strain were positive. anthracnose disease at post–harvest on fruit suppressed by the strain dm12 (90.87%). also, biocontrol efficacy on strawberry plants by drenching soil and spraying methods were 72.22% and 94.44%, respectively, 60 days after inoculation. pcr amplification represented the presence of genes of surfactin. in addition, metabolite profile of strawberry was changed on presence of bacterial strain that a number of metabolites in control treatment with maximum area percent were acetoglyceride (19.418%), acetic acid, butyl ester (4.734%) and ribitol (4.349%), in treatment inoculated with dm12 strain alone were tetramethyl–2–hexadecen (21.35%), ethylene glycol monoisobutyl ether (18.688%) and myrtenol (8.75%), in treatment inoculated with fungal pathogen alone were acetoglyceride (18.089%) and acetic acid, monoglyceride (17.96%) and in treatment inoculated with c. nymphaeae  and dm12 strain together were tert–butanethiol (36.153%), ethoxy triethyl silane (14.126%), 5–(methylamino)–1,2,3,4–thiatriazole (9.53%) and 2,3–butanediol (7.795%). some of these compounds, such as butanediol, lactose and tetradecane, which were produced in dm12 strain alone and c. nymphaeae and dm12 strain together treatments, have antifungal properties. these results showed that strain dm12 has able to decrease mycelial growth, conidial germination, fruit decay development and disease severity of strawberry anthracnose under in vitro, in vivo and greenhouse conditions. further works are required in order to understanding the interaction of dm12 with the plant and others phytopathogens and its effects on the plant defense system..