Fungi of the genus Trichoderma are economically important due to their growth-promoting effects, such as improved nutrient supply, mycoparasitism of plant-pathogens and priming of the plant defense. Due to their mycotrophic lifestyle however, they might also be antagonistic to other plant-beneficial fungi, such as mycorrhiza-forming species. Trichoderma spp. releases a high diversity of volatile organic compounds (VOCs), which likely play a decisive role in the inter-species communication. It has been shown that Trichoderma VOCs can inhibit growth of some plant pathogens, but their inhibition potentials during early interactions with mutualistic fungi remain unknown. Here, we investigated the VOC profiles of three isolates of Trichoderma species, T. harzianum, T. hamatum and T. velutinum, as well as the common ectomycorrhizal fungus Laccaria bicolor by stir bar sorptive extraction and gas chromatography – mass spectrometry (SBE-GC-MS). We further examined the fungal performance and the VOC emission profiles during confrontation of the Trichoderma species with L. bicolor in different co-cultivation scenarios. The VOC profiles of the three Trichoderma species were highly species-dependent. T. harzianum was the strongest VOC emitter with the most diverse compound pattern, followed by T. hamatum and T. velutinum. Co-cultivation of Trichoderma spp. and L. bicolor altered the VOC emission patterns dramatically in some scenarios. The co-cultivations also revealed contact degree-dependent inhibition of one of the fungal partners. Trichoderma growth was at least partially inhibited when sharing the same headspace with L. bicolor. In direct contact between both mycelia, however, L. bicolor growth was impaired, indicating that Trichoderma and L. bicolor apply different effectors when defending their territory. Multivariate analysis demonstrated that all examined individual fungal species in monoxenic cultures, as well as their co-cultivations were characterized by a distinct VOC emission pattern. The results underline the importance of VOCs in fungal interactions and reveal unexpected adjustability of the VOC emissions according to the specific biotic environments.

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Trichoderma Species Differ in Their Volatile Profiles and in Antagonism Toward Ectomycorrhiza Laccaria bicolor.

A major current challenge is to increase the food production while preserving natural resources. Agricultural practices that enhance the productivity and progressively improve the soil quality are relevant to face this challenge. Trichoderma species are widely used in agriculture to stimulate the plant growth and to control different pathogens affecting crops, representing useful tools for sustainable food production. This mini-review summarizes applications of Trichoderma strains in agriculture to control fungal pathogens, nematodes and insects, the involved biocontrol mechanisms, efficacy and inoculation forms in greenhouse, field and post-harvest conditions. Aspects of Trichoderma handling that influence on biocontrol efficacy such as preventive treatments, frequency of applications and delivery methods are discussed. Strategies useful to improve the antagonistic performance such as the use of native strains, protoplast fusion, formulation, growth on pathogen cell wall medium and combination with other antagonists in integrated treatments are discussed. This mini-review provides practical knowledge to design safe and optimal biocontrol strategies based on Trichoderma and pose challenges to expand its antagonist performance.

Trichoderma as biological control agent: scope and prospects to improve efficacy

Tomato is one of the major cash crops in the Golapar area of district Nainital in Uttarakhand (India), where farmers are facing the problem of diseases in tomato cultivation. In the present investigation, a survey of tomato fields in the Golapar area of Haldwani block was conducted. The survey revealed the occurrence of late blight, early blight, stem rot, and wilt diseases causing an average loss of 80% to tomato. To counter the above diseases, Trichoderma harzianum (Th43), Pseudomonas fluorescens (Pf173), Jas mycorrhiza (AMF), and the fungicide (Mancozeb) in different combinations applyed through soil application (SA), seedling treatment (ST), and foliar spray (FA) were evaluated for growth promotion and disease control in tomato at experimental and farmers’ fields. The results of the study revealed that in experimental field, the maximum plant height (43.67 cm), highest number of branches (7.33) per plant, highest weight of fruit (47 g), highest number of fruits (39) per plant, minimum plant mortality (4% at 30 DAT and 3.2% at 30–60 DAT), minimum plant disease index (6.85), maximum total yield (256.00 q/ha), and marketable yield (246.67 q/ha) were observed in Th+Pf+JM (SA) + Th+Pf (ST) + Mancozeb (FS). At farmer’s field, minimum plant mortality (7.31%) at 30 days after transplanting (DAT) (5.73%) in 30–60 DAT, minimum plant disease index (11.47), and maximum yield 249.91 q/ha were observed in Th+Pf+JM (SA) + Th+Pf (ST) + Mancozeb (FS) combination. So, it can be concluded that among all the treatments, integrated treatment comprising of soil application of T. harzianum, P. fluorescens, Jas mycorrhiza (AMF) + seedling treatment with T. harzianum and P. fluorescens + three foliar sprays of Mancozeb was found very effective in reducing the plant mortality, promoting the plant growth, and increasing the yield at experimental field as well as at farmers’ fields.

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Field efficacy of different combinations of Trichoderma harzianum , Pseudomonas fluorescens , and arbuscular mycorrhiza fungus against the major diseases of tomato in Uttarakhand (India)

Bacillus sp. BSp.3/aM, a beneficial rhizobacteria, was analyzed for the ability to improve plant health of chili by suppressing anthracnose disease. In the dual culture assay, the bacterium Bacillus sp. BSp.3/aM was found inhibitory to Colletotrichum capsica (6 mm). Further, upon seed priming, it reduced the seed-borne incidence of C. capsici (2%) and improved seedling vigor (1374 ± 7.15 vigor index) and germination (98 ± 0.57 %) of chili seedlings. Under greenhouse conditions, seed priming resulted in reducing the anthracnose disease incidence up to 20%. Induction of resistance against invading pathogen is through enhancing the activities of defense-related enzymes and higher accumulation of phenolic compounds in the host plant. The activity of phenylalanine ammonia-lyase (PAL; 95 units) was more at 48 hpi; peroxidase (POX; 6.49 units) at 24 hpi; polyphenol oxidase (PPO; 5.81 units) at 24 hpi and lipoxygenase (LOX; 9.9units) at 24 hpi. Maximum accumulation of the phenolics and chitinase accumulation was observed in BSp.3/aM + pathogen treated seedlings 120 hpi (94.7 μg/g tissue) and at 96 hpi (9.36 units), respectively. Thus, increased activities of defense-related enzymes (PAL, POX, PPO, LOX, and chitinase) correlated well with the decreased anthracnose incidence. Induced systemic resistance (ISR) mediated by PGPR was due to the upregulation of defense-related enzymes and by the accumulation of phenolic compounds.

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Rhizobacteria Bacillus spp. induce resistance against anthracnose disease in chili ( Capsicum annuum L.) through activating host defense response

Structural equation modeling for indicators of sustainable agriculture: Prospective of a developing country’s agriculture

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Present Status and Future Prospects of Bio-Agents in Agriculture

Effect of IGF1 gene polymorphism and expression levels on growth factors in Indian colored broilers

The green revolution has been a major boost to the agriculture sector throughout the world including India. The food production of the country increased by many fold during the 1960s and 1970s and has continued to increase since then. But, the boom of green revolution could not last long as we witnessed stagnation in the productivity of our farm lands along with soil and crop health degradation. This forced the scientific and farming community to look for efficient and ecologically safe farming systems which led to the evolution of the concept of ‘sustainable agriculture’. Sustainable agriculture is a holistic concept of agriculture which helps in meeting the needs of the present generation without affecting the future generation. It helps in maintaining optimum crop production along with maintaining soil health, conservation of natural resources and preserving ecological balance and biodiversity in agroecosystems. This review aims to create a paradigm for future studies on new and innovative techniques for sustainable crop production.

https://journals.ansfoundation.org/index.php/jans/article/download/2156/1827

Sustainable agriculture: Trends and opportunities for 21st Century

In the present investigation potential fungal and bacterial antagonists were tested under laboratory and field conditions against the phytopathogen Fusarium moniliforme var. subglutinans Sheldon, causing Pokkah Boeng disease of sugarcane. Different strains of fungal anatagonists viz; Trichoderma spp. (strains TCMS36, TCMS43, Th3, TCMS9, Th14) and bacterial antagonists viz; Pseudomonas fluorescens (strains Psf173 and Psf02) and Bacillus sp. were tested against the pathogen under in vitro conditions by employing dual culture technique and volatile assay. The results from dual culture revealed that TCMS36 showed the maximum radial growth inhibition i.e., 73.33 per cent followed by Th14 (69.01%), Psf02 (68.33%), Th3(66.04%),TCMS43 (64.7%), Bacillus sp. (63.95%) and TCMS9(63.74%). Volatile assay depicted that the maximum radial growth inhibition was found in TCMS36(70.01%) followed by TCMS9 (60.10%), Th3 (57.25%), Th14 (55.36%), Psf02 (50.83%) and Bacillus sp. (51.79%), while minimum growth inhibition was observed in Psf173 (40.49%). Further studies were conducted in field, where, Th 14, Psf02 and the consortium of both (Th 14+Psf 02) were tested through sett treatment. The minimum disease incidence was observed in the treatment where setts were treated with P. fluorescens (Psf02) followed by consortium (Th 14+Psf 02) and Th 14 i.e. 0.92%, 1.51% and 5.53%, respectively. The findings from research conclude that the fungal and bacterial antagonist strains can exert an inhibitory effect on the radial growth of Fusariu m sp. as well as reduce the disease incidence in field. Application of these antagonists in field could be a better management tool without having to depend on hazardous chemicals.

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Evaluation of fungal and bacterial antagonists for managing phytopathogen Fusarium moniliforme var. subglutinans Sheldon, causing Pokkah Boeng disease of sugarcane

Roopali Sharma

Papers

Field efficacy of different combinations of Trichoderma harzianum , Pseudomonas fluorescens , and arbuscular mycorrhiza fungus against the major diseases of tomato in Uttarakhand (India)

Present Status and Future Prospects of Bio-Agents in Agriculture

Effect of IGF1 gene polymorphism and expression levels on growth factors in Indian colored broilers

Sustainable agriculture: Trends and opportunities for 21st Century

Evaluation of fungal and bacterial antagonists for managing phytopathogen Fusarium moniliforme var. subglutinans Sheldon, causing Pokkah Boeng disease of sugarcane