Endophytic microbes modulate plant responses to abiotic stresses: a review

Many groups of microorganisms have been studied for their benefits towards humankind due to their capacity to produce natural compounds that can be valorized in many economic sectors such as agriculture. Due to the extensive use of chemicals pesticides and fertilizers, current agriculture systems facing several major problems such as emergence of resistant in pathogens and pests, soil infertility and bioaccumulation of toxic residues in the environment and particularly in foods which negatively affects human health. The use of natural products harmless to plants, humans and biodegradable constitute a promising way to overcome these problems. Modern agriculture systems are moving toward the use of beneficial microorganisms isolated from the soil, plant surfaces and inside tissues for developing eco-friendly products such as biofertilizers and biopesticides. Recent literatures show that colonization of plants by endophytes is the rule in nature and endophyte-free plant is a rare exception. Endophytes are microbes living inside plant tissues and supporting them in growth and development, as well as stresses tolerance without causing any apparent disease symptom. Abiotic stresses have a great impact on growth, production and health of plants. Many literatures show the role of endophytes in abiotic stress tolerance as well as mechanisms involved to cope with these constraints via the induction of stress-related genes and molecules. This review provides a summary of literature on how endophytes modulate plant growth and responses to abiotic stresses which may help to better understand their role in plant adaptation to environmental constraints and valorize their use in agriculture

Prospecting bacterial volatile organic compounds antifungal activities against postharvest diseases

Chemical pesticides have a plenty of negative impacts on human health and on the environment. Thus, modern agriculture cropping systems are moving towards more eco-friendly alternatives. This study aims to investigate the bioprotective effect of three volatile organic compounds (VOCs: N-Ethylaniline, 2-Heptanone and 3-Methylbutan-1-ol) produced by endophytic bacteria against 21 phytopathogenic fungal strains and their bioprotective effect on horticulture products i.e. tomato and lemon fruits and Potato tubers. The results showed that N-Ethylaniline and 3-methylbutan-1-ol had better antagonistic activity against the fungal strains by inhibiting the mycelia growth of the studied fungal strains at different concentrations. The N-Ethylaniline showed the lowest effective concentration (EC50) against B. cinerea strain S5 (0,258 mL/L headspace), Fusarium solani strain SB4.15.1 (0,496 mL/L headspace) and Colletotrichum gloeosporioides strain ManS3Fr02 (0,206 mL/L headspace). At EC50 this compound significantly reduced B. cinerea and C. gloeosporioides infections on tomato and lemon fruits, respectively. However, N-Ethylaniline didn’t showed significant effect on F. solani infection on Potato tubers. This study showed the broad spectrum of in vitro antifungal activity of N-Ethylaniline and its effect to reduce postharvest infections of some fungal diseases suggesting its potential use as a biofumigant

Endophytic microbes modulate plant responses to abiotic stresses: a review

Many groups of microorganisms have been studied for their benefits towards humankind due to their capacity to produce natural compounds that can be valorized in many economic sectors such as agriculture. Due to the extensive use of chemicals pesticides and fertilizers, current agriculture systems facing several major problems such as emergence of resistant in pathogens and pests, soil infertility and bioaccumulation of toxic residues in the environment and particularly in foods which negatively affects human health. The use of natural products harmless to plants, humans and biodegradable constitute a promising way to overcome these problems. Modern agriculture systems are moving toward the use of beneficial microorganisms isolated from the soil, plant surfaces and inside tissues for developing eco-friendly products such as biofertilizers and biopesticides. Recent literatures show that colonization of plants by endophytes is the rule in nature and endophyte-free plant is a rare exception. Endophytes are microbes living inside plant tissues and supporting them in growth and development, as well as stresses tolerance without causing any apparent disease symptom. Abiotic stresses have a great impact on growth, production and health of plants. Many literatures show the role of endophytes in abiotic stress tolerance as well as mechanisms involved to cope with these constraints via the induction of stress-related genes and molecules. This review provides a summary of literature on how endophytes modulate plant growth and responses to abiotic stresses which may help to better understand their role in plant adaptation to environmental constraints and valorize their use in agriculture

Prospecting bacterial volatile organic compounds antifungal activities against postharvest diseases

Chemical pesticides have a plenty of negative impacts on human health and on the environment. Thus, modern agriculture cropping systems are moving towards more eco-friendly alternatives. This study aims to investigate the bioprotective effect of three volatile organic compounds (VOCs: N-Ethylaniline, 2-Heptanone and 3-Methylbutan-1-ol) produced by endophytic bacteria against 21 phytopathogenic fungal strains and their bioprotective effect on horticulture products i.e. tomato and lemon fruits and Potato tubers. The results showed that N-Ethylaniline and 3-methylbutan-1-ol had better antagonistic activity against the fungal strains by inhibiting the mycelia growth of the studied fungal strains at different concentrations. The N-Ethylaniline showed the lowest effective concentration (EC50) against B. cinerea strain S5 (0,258 mL/L headspace), Fusarium solani strain SB4.15.1 (0,496 mL/L headspace) and Colletotrichum gloeosporioides strain ManS3Fr02 (0,206 mL/L headspace). At EC50 this compound significantly reduced B. cinerea and C. gloeosporioides infections on tomato and lemon fruits, respectively. However, N-Ethylaniline didn’t showed significant effect on F. solani infection on Potato tubers. This study showed the broad spectrum of in vitro antifungal activity of N-Ethylaniline and its effect to reduce postharvest infections of some fungal diseases suggesting its potential use as a biofumigant

Activity assessment of tomato endophytic bacteria bioactive compounds for the postharvest biocontrol of Botrytis cinerea

International audienc

Genome sequences of bacterial biocontrol agents isolated from Solanum lycopersicum and Medicago truncatula in Tunisia

International audienceThe whole-genomes shotgun sequences of 6 bacterial biocontrol agents isolated from Medicago truncatula and Solanum lycopersicum collected in the North of Tunisia are presented in this study. The genome sequences supplement the existing genomics resources and give us an insight into the biodiversity of bacteria associated with plants and prospect key genes required for their endophytic behaviour, interactions with their hosts and biocontrol activity traits against plant pathogens. </p

Screening of Tomato Seed Bacterial Endophytes for Antifungal Activity Reveals Lipopeptide Producing Bacillus siamensis Strain NKIT9 as a Potential Bio-Control Agent

The current study investigates the diversity pattern and fungicidal potential of bacterial endophytes isolated from two different organic varieties of tomato plants (V1 and V2). A total of seventy-five bacterial isolates identified by 16S rRNA gene sequencing revealed a majority of genus as Bacillus and one Planococcus, which were grouped into eight different species. The Shannon diversity H’ (1.56), Simpson’s index of diversity (0.93), Magalef’ index (2.23), Evenness (0.96), and Species richness (7) indicated the high endophytic bacterial diversity in the V1 variety of the tomato. Bacterial endophytes isolated from both of the varieties were screened for their antifungal activity against five economically critical fungal pathogens (viz., Botrytis cinerea, Rhizoctonia solani, Fusarium solani, Verticillium lateritium, and Alternaria solani) of tomato crop through dual culture assay. The data revealed B. siamensis strain NKIT9 as the most potent antagonist, significantly (p &amp;lt; 0.05) inhibiting the mycelial growth between 75 to 90% against selected fungal pathogens. High bioactivity of lipopeptide extract of strain NKIT9 was recorded against R. solani with minimum IC50 value of 230 μg/ml. The Ultra Performance Liquid Chromatography-High Definition Mass Spectrometry (UPLC-HDMS) analysis of this lipopeptide extract revealed the presence of Surfactin and Bacillomycin D. Furthermore, in-vitro results showed that the selected bacterial strain significantly minimized the disease incidence in damping-off assay which makes this strain a promising antifungal bio-control agent. Moreover, in the pot experiment the NKIT9 increased the fruit yield by 59.2% compared with the untreated R. solani infested control.</jats:p

Screening of tomato seed bacterial endophytes for antifungal activity reveals lipopeptide producing <i>Bacillus siamensis</i> as a potential bio-control agent

ABSTRACTThe current study investigates the diversity pattern and fungicidal potential of bacterial endophytes isolated from two different organic varieties of tomato plants (V1 and V2). A total of seventy-four bacterial isolates identified by 16S rRNA sequencing revealed a single genus Bacillus with 16 different species. The Shannon diversity H’ (1.45), Simpson’s index of diversity (0.9), Magalef’ index (2.1), Evenness (0.96), and Species richness (8) indicated the high endophytic bacterial diversity in the V1 variety of the tomato. Bacterial endophytes isolated from both the varieties were screened for their antifungal activity against five economically critical fungal pathogens (viz., Botrytis cinerea, Rhizoctonia solani, Fusarium solani, Verticillium lateritium, and Alternaria solani) of tomato crop through dual culture assay. The data revealed B. siamensis KCTC 13613(T) as the most potent antagonist significantly (p &lt; 0.05), inhibiting the mycelial growth between 75 to 90% against selected fungal pathogens. High bioactivity of lipopeptide extract of B. siamensis was recorded against R. solani with IC50 value of 72 ppm. The UPLC-HDMS analysis of this lipopeptide extract revealed the presence of, Surfactin and Bacillomycin D.</jats:p