Trichoderma harzianum mitigates salt stress in cucumber via multiple responses.

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.

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

Many Trichoderma spp. are successful plant beneficial microbial inoculants due to their ability to act as biocontrol agents with direct antagonistic activities to phytopathogens, and as biostimulants capable of promoting plant growth. This work investigates the effects of treatments with three selected Trichoderma (strains T22, TH1 and GV41) to strawberry plants on the productivity, metabolites and proteome of the formed fruits. The Trichoderma applications stimulated plant growth, increased strawberry fruit yield, and favored selective accumulation of anthocyanins and other antioxidants in red ripened fruits. Proteomic analysis of fruits harvested from the plants previously treated with Trichoderma demonstrated that the microbial inoculants highly affected the representation of proteins associated with responses to stress/external stimuli, nutrient uptake, protein metabolism, carbon/energy metabolism and secondary metabolism, also providing a possible explanation to the presence of specific metabolites in fruits. Bioinformatic analysis of these differential proteins revealed a central network of interacting molecular species, providing a rationale to the concomitant modulation of different plant physiological processes following the microbial inoculation. These findings indicated that the application of Trichoderma-based products exert a positive impact on strawberry, integrating well with previous observations on the molecular mechanisms activated in roots and leaves of other tested plant species, demonstrating that the efficacy of using a biological approach with beneficial microbes on the maturing plant is also able to transfer advantages to the developing fruits.

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Trichoderma Applications on Strawberry Plants Modulate the Physiological Processes Positively Affecting Fruit Production and Quality.

The fungal species belonging to the Trichoderma genus are the most promising microorganisms which improve plant growth by enhancing nutrient uptake and preventing them against environmental biotic and abiotic stresses. This study was aimed to evaluate the effects of three efficient Trichoderma isolates on tomato growth under water-deficit stress. Ten isolates of Trichoderma were in vitro assayed for auxin production, phosphate solubilizing activity and siderophore production traits, and three efficient isolates were selected for pot culture experiment according to the above assessments. Treatments including inoculation with T1 (Trichoderma longibrachiatum KH), T2 (T. longibrachiatum MA), T3 (T. harzianum), NT1 (negative control; without fungi) and NT2 (positive control; without fungi but with chemical fertilizers) at three soil moisture levels of W0 (no water-deficit stress), W1 (medium stress) and W2 (severe stress) were applied to the pots on seedling transplanting. The results revealed that the shoot and root dry matter, root volume, leaf water potential and stomatal conductance decreased as water-deficit stress increased. However, the decrease was significantly lower in fungal treatments than non-inoculated ones. Inoculations with T1, T2 or T3 increased shoot dry weight by 97.2, 17.2 and 18.96% compared to the positive control (NT2) and by 32.81, 19.41 and 20.42% compared to the negative control (NT1), respectively. The highest root volume was recorded in T1 inoculation. This fungus increased root volume by 91.74% and 96.37% compared to the NT1 and NT2 controls, respectively. Moreover, the T1 inoculation enhanced shoot potassium uptake by 37.23 and 34.36% and that of root by 63.25% and 62.02% compared to the NT1 and NT2 controls, respectively.

Effects of Trichoderma isolates on tomato growth and inducing its tolerance to water-deficit stress

Biological control agents (BCAs) are gaining more attention as alternatives to the chemical pesticides for management of pests and diseases in agricultures. It offers an ecofriendly way for plant health management (PHM), and it also helps to reduce the excessive use of toxic chemicals or pesticides. The BCAs considered as the most promising technology for sustainable agriculture. Various beneficial BCAs have been known for PHM but need effective adoption together with standardization of bioformulations for field applications. The mechanisms of BCAs in PHM mainly include direct (parasitism, hyperparasitism, commensalism), indirect (competition, systemic acquired or induced systemic resistance), or mixed antagonistic modes (production of antibiotics, siderophores, lytic enzyme, and volatile organic substances). Apart from their role in plant growth promotion, plant growth-promoting rhizobacteria (PGPR) and fungi (PGPF) also act as BCAs that function through either of the mechanisms. The PGPR/PGPF possesses many traits that serve them as potential BCAs, and therefore possess great promise for successful application in sustainable agriculture. In this chapter, different approaches for BCAs applications and their mechanism in PHM especially for disease and pest (DP) management are discussed. Also, the relationship between the PGPR/PGPF diversity and their application in biological control is discussed. Furthermore, we have summarized the global-Indian scenario of current research including state-of-the-art technological advances in PGPR/PGPF-mediated DP management.

Plant Growth-Promoting Rhizobacteria (PGPR) and Fungi (PGPF): Potential Biological Control Agents of Diseases and Pests

Trichoderma harzianum containing 1-aminocyclopropane-1-carboxylate deaminase and chitinase improved growth and diminished adverse effect caused by Fusarium oxysporum in soybean.

Yuting He

Papers

Trichoderma harzianum containing 1-aminocyclopropane-1-carboxylate deaminase and chitinase improved growth and diminished adverse effect caused by Fusarium oxysporum in soybean.