Phytohormones (Auxin, Gibberellin) and ACC Deaminase In Vitro Synthesized by the Mycoparasitic Trichoderma DEMTkZ3A0 Strain and Changes in the Level of Auxin and Plant Resistance Markers in Wheat Seedlings Inoculated with this Strain Conidia

Abstract

Both hormonal balance and plant growth may be shaped by microorganisms synthesizing phytohormones, regulating its synthesis in the plant and inducing plant resistance by releasing elicitors from cell walls (CW) by degrading enzymes (CWDE). It was shown that the Trichoderma DEMTkZ3A0 strain, isolated from a healthy rye rhizosphere, colonized the rhizoplane of wheat seedlings and root border cells (RBC) and caused approximately 40% increase of stem weight. The strain inhibited (in over 90%) the growth of polyphagous Fusarium spp. (F. culmorum, F. oxysporum, F. graminearum) phytopathogens through a mechanism of mycoparasitism. Chitinolytic and glucanolytic activity, strongly stimulated by CW of F. culmorum in the DEMTkZ3A0 liquid culture, is most likely responsible for the lysis of hyphae and macroconidia of phytopathogenic Fusarium spp. as well as the release of plant resistance elicitors. In DEMTkZ3A0 inoculated plants, an increase in the activity of the six tested plant resistance markers and a decrease in the concentration of indoleacetic acid (IAA) auxin were noted. IAA and gibberellic acid (GA) but also the 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase (ACCD) enzyme regulating ethylene production by plant were synthesized by DEMTkZ3A0 in the liquid culture. IAA synthesis was dependent on tryptophan and negatively correlated with temperature, whereas GA synthesis was positively correlated with the biomass and temperature.

How Do Trichoderma Genus Fungi Win a Nutritional Competition Battle against Soft Fruit Pathogens? A Report on Niche Overlap Nutritional Potentiates

“…to more effectively colonize numerous and various niches [ 34 ]. Colonization is the very first step in the use of a wide array of other biological control mechanisms, such as antibiosis, antagonism, mycoparasitism, and the induction of plant defence responses [ 35 ].…”

Deciphering Trichoderma–Plant–Pathogen Interactions for Better Development of Biocontrol Applications

“…Moreover, the finely tuned plant hormonal homeostasis required for proper development, reproduction, and response to various stress conditions can be influenced by microorganisms synthesizing phytohormones. Phytohormones include different categories such as auxins, cytokinins, ethylene (Et), gibberellins, and abscissic acid (ABA), as well as hormone-like substances such as brassinosteroid, oligosaccharines, bioamines, salicylates–salicylic acid (SA), and jasmonic acid (JA) [ 37 ]. Microbially-derived phytohormones can help plants withstand biotic and abiotic stress conditions.…”

“…Several members of Trichoderma spp. can produce phytohormones (auxin, gibberellin) and the enzyme 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase can regulate the level of plant ethylene [ 37 ]. Moreover, volatiles from T. asperellum IsmT5 upregulated the plant SA production by 61% and ABA by 40% compared to plants not exposed to volatiles [ 42 ].…”

Differences in Production, Composition, and Antioxidant Activities of Exopolymeric Substances (EPS) Obtained from Cultures of Endophytic Fusarium culmorum Strains with Different Effects on Cereals

“…Earlier studies of the three tested strains of Fusarium culmorum showed a clear diversity of their interaction with cereals, colonization of root [58,60] and root border cells [59] and the ability to synthesize toxins [58], CWDEs [63,64] and phytohormones [60,65]. The ability to induce plant resistance has been demonstrated for these Fusarium culmorum strains [58].…”