Trichoderma species — opportunistic, avirulent plant symbionts

Abstract

Trichoderma spp. are free-living fungi that are common in soil and root ecosystems. Recent discoveries show that they are opportunistic, avirulent plant symbionts, as well as being parasites of other fungi. At least some strains establish robust and long-lasting colonizations of root surfaces and penetrate into the epidermis and a few cells below this level. They produce or release a variety of compounds that induce localized or systemic resistance responses, and this explains their lack of pathogenicity to plants. These root-microorganism associations cause substantial changes to the plant proteome and metabolism. Plants are protected from numerous classes of plant pathogen by responses that are similar to systemic acquired resistance and rhizobacteria-induced systemic resistance. Root colonization by Trichoderma spp. also frequently enhances root growth and development, crop productivity, resistance to abiotic stresses and the uptake and use of nutrients.

Isolation and Characterization of Trichoderma spp. for Antagonistic Activity Against Root Rot and Foliar Pathogens

“…The antagonism by Trichoderma spp. against many soils borne plant pathogen has been established [6,22,23]. Strong antagonism by Trichoderma spp.…”

“…It is well known that Trichoderma spp. have the potential to produce cell wall degrading enzymes by using the materials that are present in the growth medium [6]. Production of hydrolytic enzymes such as b-1,3-glucanase, chitinase, cellulase and proteinase increased significantly when Trichoderma spp.…”

“…Trichoderma spp. are among the most frequently isolated soil fungi and present in plant root systems [6]. However, there is still considerable interest in finding more efficient mycoparasitic fungi especially within Trichoderma spp., which differ considerably with respect to their biocontrol effectiveness.…”

Plant immune responses triggered by beneficial microbes

“…Classical examples of symbiotic microorganisms are mycorrhizal fungi that aid in the uptake of water and minerals, notably phosphate [1], and Rhizobium bacteria that fix atmospheric nitrogen for the plant [2]. Several other types of beneficial soil-borne microbes, such as plant growth promoting rhizobacteria and fungi, can stimulate plant growth by suppressing plant diseases [3][4][5][6]7 ] or insect herbivory [8 ]. This biological control activity is exerted either directly through antagonism of soil-borne pathogens or indirectly by eliciting a plant-mediated resistance response [3,9].…”

Peptaibiomics: Screening for Polypeptide Antibiotics (Peptaibiotics) from Plant-ProtectiveTrichoderma Species

“…Trichogin GA IV exhibits a considerable membraneperturbing activity which is illustrated by a two-state transition controlled by peptide concentration: at low concentrations, the molecule is situated parallel to the membrane surface in a carpet-like manner with its four polar Gly residues oriented towards the aqueous phase. Hydrophobic residues, including the N-octanoyl group as well as Leu 3,7 and Ile 10 , face the membrane, thus stabilizing the interaction between the peptide and the lipid bilayer. By increasing peptide concentration until membrane leakage is observed, a cooperative transition occurs.…”