Endophytic Microbes
Mycology
INTRODUCTION o Pseudomonas (Pseudomonas
• Abiotic stresses put the plant metabolism fluorescens)
out of homeostasis, necessitating the plant o Azospirillum (Azospirillum
to harbor some advanced genetic and brasilense)
metabolic mechanisms within the cellular o Bacillus
system • Endophytic stage has been substantiated
• Development of stress tolerance in plants for many
o Strategy to cope with the negative o Proteobacteria
effects of adverse environmental o Firmicutes
condition o Filamentous Actinobacteria
• Endophytic microorganisms offer
o Enhancement of plant growth
o Enhanced production of natural
compounds
o Can be biocontrol agents due to
their antagonistic properties
WHAT ARE ENDOPHYTIC MICROBES
• Endophyte
o microorganisms which lives inside a Azospirillum brasilense
healthy plant tissues without causing
apparent harm to the host (Bacon
and White, 2020)
o Endo = “endon” meaning “within”
o Phyte = “phyton” meaning “plant
• De Bary
o First to use the term in 1886
o Used to denote all those microbes Burkholderia sp.
residing inside the living healthy
plant
• Ubiquitous
• They interact biochemically and genetically
inducing the beneficial effects in plant
growth and defense without causing
pathogenic symptoms
• Beneficial effects
o Similar to but higher than plant
growth promoting rhizobacteria Pseudomonas fluorescens
(PGPR)
o Allows survival of severe
environmental conditions due to
unique ecological niche
BACTERIAL ENDOPHYTES
• Majority belongs to genera
o Pseudomonas
o Burkholderia
o Bacillus
• Species of competitive rhizosphere
bacteria often found as colonizers of
internal plant tissues
BS BIOLOGY (MICROBIOLOGY TRACK) | 1
, Endophytic Microbes
Mycology
TWO MAJOR GROUPS OF ENDOPHYTIC FUNGI
I. C-Endophytes/Class I endophytes
o C – clavicipitaceous
o Infects some grasses
o Most common
o Studied species
▪ Epichloe
▪ Neotyphodium – asexual
derivatives of Epichloe
o Examples of Class I endophytic
fungi that conferred abiotic stress BENEFICIAL EFFECTS OF ENDOPHYTES
tolerance
• Direct plant growth promotion
II. NC-Endophytes/Class II endophytes o Phytostimulation
o NC – non-clavicipitaceous o Biofertilization
o In tissues of: • Indirect plant growth promotion
▪ Non-vascular plants o Disease suppression
▪ Gymnosperms o Protection against pest and
▪ Angiosperms herbivores
o Typically, Ascomycotina fungi o Induction of stress tolerance
o Examples of Class II endophytic o Rhizoremediation
fungi that conferred abiotic stress • Mechanisms are proposed to explain the
tolerance beneficial effects of endophytes
o Production of phytohormones
(auxins, gibberellins, cytokinin)
o Biological nitrogen fixation
o Mobilization of phosphorus
o Suppression of stress related plant
ethylene synthesis by 1-
aminocyclopropane-1-
carboxylate (ACC) deaminase
activity
o Induced systemic
resistance/tolerance against abiotic
stresses
o Plant defense mechanisms by
▪ Antagonistic substances
(siderophores, Hydrogen
Cyanide [HCN])
BS BIOLOGY (MICROBIOLOGY TRACK) | 2
Mycology
INTRODUCTION o Pseudomonas (Pseudomonas
• Abiotic stresses put the plant metabolism fluorescens)
out of homeostasis, necessitating the plant o Azospirillum (Azospirillum
to harbor some advanced genetic and brasilense)
metabolic mechanisms within the cellular o Bacillus
system • Endophytic stage has been substantiated
• Development of stress tolerance in plants for many
o Strategy to cope with the negative o Proteobacteria
effects of adverse environmental o Firmicutes
condition o Filamentous Actinobacteria
• Endophytic microorganisms offer
o Enhancement of plant growth
o Enhanced production of natural
compounds
o Can be biocontrol agents due to
their antagonistic properties
WHAT ARE ENDOPHYTIC MICROBES
• Endophyte
o microorganisms which lives inside a Azospirillum brasilense
healthy plant tissues without causing
apparent harm to the host (Bacon
and White, 2020)
o Endo = “endon” meaning “within”
o Phyte = “phyton” meaning “plant
• De Bary
o First to use the term in 1886
o Used to denote all those microbes Burkholderia sp.
residing inside the living healthy
plant
• Ubiquitous
• They interact biochemically and genetically
inducing the beneficial effects in plant
growth and defense without causing
pathogenic symptoms
• Beneficial effects
o Similar to but higher than plant
growth promoting rhizobacteria Pseudomonas fluorescens
(PGPR)
o Allows survival of severe
environmental conditions due to
unique ecological niche
BACTERIAL ENDOPHYTES
• Majority belongs to genera
o Pseudomonas
o Burkholderia
o Bacillus
• Species of competitive rhizosphere
bacteria often found as colonizers of
internal plant tissues
BS BIOLOGY (MICROBIOLOGY TRACK) | 1
, Endophytic Microbes
Mycology
TWO MAJOR GROUPS OF ENDOPHYTIC FUNGI
I. C-Endophytes/Class I endophytes
o C – clavicipitaceous
o Infects some grasses
o Most common
o Studied species
▪ Epichloe
▪ Neotyphodium – asexual
derivatives of Epichloe
o Examples of Class I endophytic
fungi that conferred abiotic stress BENEFICIAL EFFECTS OF ENDOPHYTES
tolerance
• Direct plant growth promotion
II. NC-Endophytes/Class II endophytes o Phytostimulation
o NC – non-clavicipitaceous o Biofertilization
o In tissues of: • Indirect plant growth promotion
▪ Non-vascular plants o Disease suppression
▪ Gymnosperms o Protection against pest and
▪ Angiosperms herbivores
o Typically, Ascomycotina fungi o Induction of stress tolerance
o Examples of Class II endophytic o Rhizoremediation
fungi that conferred abiotic stress • Mechanisms are proposed to explain the
tolerance beneficial effects of endophytes
o Production of phytohormones
(auxins, gibberellins, cytokinin)
o Biological nitrogen fixation
o Mobilization of phosphorus
o Suppression of stress related plant
ethylene synthesis by 1-
aminocyclopropane-1-
carboxylate (ACC) deaminase
activity
o Induced systemic
resistance/tolerance against abiotic
stresses
o Plant defense mechanisms by
▪ Antagonistic substances
(siderophores, Hydrogen
Cyanide [HCN])
BS BIOLOGY (MICROBIOLOGY TRACK) | 2
