Recent climate changes have increased the severity of environmental biotic and abiotic stresses and had widespread effects on global agricultural production. These stresses can be perceived as a worldwide challenge and are the main predicaments that hinder crop yield, value, total food security, and natural ecosystems. Field crop production confronts biotic and abiotic risks, such as droughts, floods, storms, and soil toxicity. Soil is the foundation of agriculture. All harvests for human nutrition and animal fodder rely on healthy soil. The effects of climate change have deteriorated the quality of this vital natural reserve. In addition to the vast amounts of anthropogenic garbage, the alien plant Eucalyptus and its accumulated leaves degrade soil quality. The Eucalyptus genus, with more than 800 species, is the most significant in the botanical family Myrtaceae. It is an Australian native and has an extensive global distribution (Hassine et al., 2013). It was brought to the region that is now Bangladesh in the 1930s. Going back in time, the tea estates in eastern Bangladesh carelessly introduced this tree as an ornamental species in the 1930s (Davidson and Das, 1985). When the Ministry of Environment and Forest department (MEF) discovered the negative impacts of Eucalyptus in 1995, they removed it from their tree planting program and made the public aware of those problems (Babu, 2018). They are aggressive species in Bangladesh because they can cause groundwater levels to drop and provide little benefit to native wildlife that prefers other tree species.

One of Eucalyptus’ main drawbacks is an extremely high rate of transpiration that causes detrimental effects on the environment. Compared to other trees in the country, Eucalyptus contributes much more to draught through transpiration 18–20 times higher. Groundwater levels may drop by 20% if Eucalyptuses are permitted to grow around a freshwater reserve for around 10 years, while other trees show growth at a rate of 10%. The Eucalyptus tree is more valuable economically, but it is also more invasive than other trees because its characteristics make it more attractive for planting (Babu, 2018). Unfortunately, because nurseries throughout the nation were producing and selling large numbers of these saplings, it was already too late to stop the out-of-control practice of Eucalyptus plantation. The environment is in grave danger as Eucalyptus plantations are currently so pervasive that they can be found in large numbers on almost every yard, office building grounds, by the side of the road, and along railroad tracks, especially in the northern parts of Bangladesh (Bogura, Gaibandha, Rangpur, Dinajpur, Panchagarh, Nilphamari, Thakurgaon, and Kurigram).

Environmental groups are concerned about the negative effects of Eucalyptus trees on the environment. These difficulties include high transpiration rates, declining soil fertility, incompatibility with the preservation of biodiversity, and allopathic impacts of Eucalyptus spp. that impede undergrowth regeneration (Aweto and Moleele, 2005; Cao et al., 2010; Cortez et al., 2014). Lane et al. (2004) in China discovered the development of Eucalyptus plantations lowers water tables and decreases the amount of water available for irrigation on lands previously used for crops or occupied by native trees and grasses due to the plant’s deep and extensive root system and soil hydrophobicity (Lane et al., 2004). Even the tree’s leaves are not amenable to easy decomposition and cause soil damage. Eucalyptus planted as a crop with short rotation for high biomass production depletes soil nutrients rapidly. A biocide oil is present in Eucalyptus leaves. It prevents the majority of soil bacteria from surviving and decomposing the leaves. However, although it takes a little longer than with leaves of other types of trees, they do degrade. They require a little more time to dry out than other leaves because of the oil content. The availability of nutrients to the plants also depends on the degree of breakdown. There is a need to speed up the decomposition that is incorporated into the field due to the harmful environmental effects of undecomposed leaves and the consequences of crop production loss. The high water use of Eucalyptus trees also contributes to desertification in Bangladesh’s northern region, and ground water level drops harm natural agriculture ecosystems.

Microbial inoculants may assist in reducing such hazards by hastening the leaf breakdown process and relieving the plants from water-stressed conditions. Serendipita indica is a phyto-promotional, mutualistic root endosymbiont that can be grown axenically and imitates the capabilities of typical arbuscular mycorrhizal (AM) fungus (Narayan et al., 2021). This fungus has the ability to colonize the roots of a variety of higher plants and offers them numerous benefits (Unnikumar et al., 2013; Verma et al., 2021; Abuhena et al., 2022a). Additionally, Serendipita indica root endophyte increases plants’ tolerance and resistance to drought (Jogawat et al., 2016; Prasad et al., 2019). It effectively attaches to the root system and develops a vast root network of hyphal filaments that serve as extensions, outwardly extending the rhizosphere. It boosts a plant’s ability to absorb water, macronutrients, and micronutrients, and tolerate drought (Narayan et al., 2017).

Soil microorganisms play a part in the decomposition process since they are the ones that transform agricultural residues into soil organic matter. According to the study, the decomposition of rice straw is a multi-step, complex process that involves a variety of microbial species. The fungus Trichoderma is one of the most prevalent microorganisms that degrade rice straw. Trichoderma sp. is classified as a decomposer fungus due to its saprophyte nature, and as such, its function is to provide free organic materials, particularly during the supply process of compost. Prior studies have suggested that Trichoderma spp. may speed up the breakdown of leaves (Organo et al., 2022). According to reports, Trichoderma spp. may quickly break down household and agricultural waste without producing unpleasant odors. With the aid of a cellulase enzyme, Trichoderma spp. can break down leaves that include components such as cellulose (Organo et al., 2022). Trichoderma spp. can produce enzymes like cellulase, cellobiose (β-Glucosidase), and chitinase. As the cellulase enzyme is a multi-enzyme made up of cellobiohydrolase, endoglucanase, and β-glucosidase, it is an enzyme that takes part in the breakdown of organic matter. Trichoderma can enhance crop output, resistance to abiotic stresses, uptake and use of nutrients, and root growth and development (Sood et al., 2020). Throughout the growth phase, it can cause systemic resistance in plants (Nawrocka and Małolepsza, 2013). Trichoderma isolates infiltrate the rhizosphere of plants and increase the variety of the soil microbiome (Saravanakumar et al., 2017). The lack of highly efficient spores for these organisms restricts novel applications, besides the potential for Trichoderma strains in boosting plant health and decomposition. Trichoderma is most frequently grown on conventional solid media. Solid-state fermentation (SSF) produces more resilient and active spores with a longer lifespan, and higher resistance (Naeimi et al., 2020). However, spore concentration and stability are typically poor, and contaminations occur frequently during liquid fermentation operations. Semi-solid fermentation can generate healthy spores. As a result, novel techniques utilizing various alternative cultivation conditions and nutrients can produce bio-sustaining spores of Trichoderma.

Therefore, a combined strategy was adopted here by applying Trichoderma fungi to accelerate the decomposition of the Eucalyptus leaves in the low pH soil of a rice field. In particular, we produced stress-tolerated Trichoderma spores using lactic acid mixed wheat agar to induce the spores’ biosustaining potential. Furthermore, the improvement in the rice field ecosystem was fostered by mycorrhizae networking, minimizing the water scarcity hazard caused by Eucalyptus trees.

Eucalyptus leaf degradation by microbial inoculum provides a two-fold advantage: one for ecosystem restoration and the other for agriculture yield improvement by increasing nutrient availability. Because of the various ecological hazards created by Eucalyptus, which include drops in groundwater level and biocidal activity of accumulated leaves, they pose an unknown danger to soil ecosystems, where microbial processing is necessary for rapid degradation of the leaves (Abuhena et al., 2022a). This process is crucial from the perspective of world food security and environmental sustainability because of the large volume of waste materials that are generated and can cause environmental hazards. All the waste produced by agro-industrial developments as well as unethical human activities can be processed into beneficial products by using microorganisms (Sadh et al., 2018). Microbes available on-site can meet the microbial inoculum requirements of the agricultural areas. It will minimize the impending hazards in the food sector and ecosystem restoration. The active agent of microbial inoculum should have waste-degrading capacity along with several plant growth-promoting features for application under these conditions (Abuhena et al., 2022c). In this study, we isolated Trichoderma strains from different agroecological zones from samples like decaying wood and rhizosphere soil, based on indications that the isolates may be good degraders and beneficial for plants. Bioactivity assays revealed that the isolates produce IAA, solubilize phosphate, secrete chitinase and β-1,3-glucanase, and show antagonism against phytopathogens such as Sclerotium theobromae, Curvularia spicifera, Alternaria alternate, and Fusarium equiseti (Abuhena et al., 2022c).

Since microorganisms have a wide range of physiological properties, nutrients have a significant impact on their growth. In addition to nutrients, other factors such as pH, temperature, and aeration are also important for Trichoderma growth. The growth structures of Trichoderma, such as hyphae, mycelia, chlamydospore, and spore, as well as the techniques of production, all have an impact on their potential (Hewavitharana et al., 2018). The LAISS method, which is discussed in this article, was developed to be used for the production of Trichoderma spores that can endure stressful situations including low pH and nutrient scarcity. pH and nutrition seem to be the most crucial variables, according to the results of using this technique. Lower pH and nutritional stress (WA) led to the production of more spores with higher densities, whereas normal growth circumstances in PDA resulted in the production of fewer spores with lower densities. The quantity, density, pureness, and sustainability of spores are important considerations when choosing a production strategy. In this research, LAISS was found to be a suitable strategy for spore production, most possibly owing to the presence of limited soluble sugar, nitrogen content, fiber, and starches in WA that Trichoderma utilizes (Mohamed et al., 2011). The quantity, density, and purity of the concentrated spore (1.38 × 10¹¹ CFU/g) produced by the LAISS were noticeably better than those produced by conventional substrate-based SSF (Sachdev et al., 2018; Naeimi et al., 2020; Mulatu et al., 2021). Spores with a high initial moisture content must be dried to a low moisture level. On the other hand, rapid drying will result in a certain proportion of cells dying (Jin and Custis, 2011). The method employed in this study resulted in distinctive biosustained spores without the need for drying to change the moisture content. This method conserved the spore’s vitality by preventing contamination, which also decreases downstream spore viability. Previous studies have demonstrated that dry and aerial spores are significantly more bio-sustainable, which supports and confirms the utilization of spore culture on WA in this method (Naeimi et al., 2020; Mulatu et al., 2021).

Eucalyptus trees have very hazardous effects on the ecosystem and crop yields due to their growth pattern and toxic leaves. Eucalyptus leaves are decomposed by beneficial fungi, that turn the hazardous leaves into organic matter. The benefits of greater organic matter in the soil include a better environment for soil organisms, a reserve of plant nutrients, improved soil structure that encourages root growth, and improved aeration. Numerous research claims that Eucalyptus trees produce large amounts of litter that is rich in lignin, phenol, and C:N ratios (Castro-Díez et al., 2012). The benefits of Trichoderma for composting have been extensively researched. According to reports, Trichoderma harzianum inoculation of straw-based compost piles resulted in a composting time that was less than half that of traditional approaches (Cuevas, 1997). Another study found that treating rice straw with Trichoderma harzianum and cow dung slurry increased the population of beneficial bacteria and increased crop yield (Sannathimmappa et al., 2015). The decomposition times of empty fruit bunches and palm oil mill effluent were said to have been reduced from 4 to 6 months to 21 to 45 days (Amira et al., 2011). In this study, we investigated the biosustainability, growth pattern, and degrading potential of various Trichoderma isolates on Eucalyptus leaves. Although all of the isolates were grown on Eucalyptus leaves, their growth patterns and degrading potential varied. With spore densities of 5.26 × 10⁸ (CFU/g) and 7.05 × 10⁷ (CFU/g), respectively, strains TI04 (Trichoderma viride) and TI15 (Trichoderma citrinoviride) demonstrated the highest growth on leaves. Isolates TI15 and TI04 both showed leaf weight losses of 31.33% and 26.8% after 15 days of incubation, respectively. Pozo, Cortes et al., and Canhoto reported that E. globulus lost 50% of its weight in 30–50 days, 76 days, and 84 days, respectively (Pozo, 1993; Cortes et al., 1994; Canhoto and Graca, 1995). The majority of the decomposing process did not investigate the bio-sustainability and spore density of Trichoderma on degraded leaves. But according to Organo et al., rice straw had the highest cell density (1.3 × 10⁵ CFU/g), which also confirmed the presence of contaminants (Organo et al., 2022). In this present experiment, excellent sporulation (5.26 × 10⁸ CFU/g), with no contaminants detected on the leaf surface or in the harvested degraded materials, was achieved.

In a rice seedling experiment, we used Serendipita indica and biosustained Trichoderma spores from degraded Eucalyptus leaves. The plant-friendly properties of the strain, such as phosphate solubilization, IAA production, cell wall degrading enzyme production, and siderophore synthesis, benefited rice seedlings. The growth of rice seedlings in terms of shoot length (cm), root length (cm), and biomass (g) was improved by strains TI04 and TI15. Moreover, the microbial community, nutrients, and soil texture all have an impact on Serendipita indica colonization (Dias et al., 2020). In our study, Trichoderma spores with degraded leaves enhanced SI mycorrhizae’s root association. In seedlings treated with TI15 and TI04, the rates (percentage) of SI colonization were 88.42 and 84.75, respectively. This represents an increase of 12.9% and 8.3%, respectively, over the sole use of SI. Trichoderma and mycorrhizae are widely utilized in agriculture as advantageous microbes, but little is documented about the molecular variations in the roots when these fungi are combined. According to reports, applying Trichoderma and mycorrhizae together improves the nutritional content of a variety of plants, including cucumbers, tomatoes, and melon (Poveda et al., 2019). However, when these two fungi are combined, adverse impacts on plants have also been reported (Poveda et al., 2019). However, this will be the first time that it has been documented that Serendipita indica colonization was increased by the application of Trichoderma spores with degraded leaves, which may aid in the restoration of the soil microbial community in degraded ecosystem.

In the current study, Trichoderma biosustained spores (TI04 and TI15) significantly increased rice yield under both CP and AFW conditions. Additionally, the SI colonization improved in field conditions (accumulated Eucalyptus leaf) despite facing low pH stress and draught stress. According to different articles, Cao et al. observed lower soil pH levels in Eucalyptus spp. plantations, ranging from 4.2 to 4.5, whereas Alemie detected decreased soil pH ranging between 3.5 and 4.0 under Eucalyptus spp. trees (Cao et al., 2010; Alemie et al., 2013). As soil biological activities are decreased in acidic soils, Castro-Dez et al. found that low soil pH restricts the growth and activity of decomposing soil microorganisms (Mohamed et al., 2011). According to Berendse, soil trace elements including manganese (Mn) and aluminum (Al) become hazardous for the majority of plant growth at pH values below 5.5 (Berendse, 1998). Additionally, in acidic soils, nutrients like phosphorus and nitrogen usually combine with Al and Fe to produce insoluble compounds that become adsorbed and are inaccessible to plants.

In this study, the risks associated with an acidic pH were reduced because it has been noted that a variety of fungal species can alkalinize their extracellular matrix under specific circumstances. One of these is carbon deficiency, which occurs when there is little glucose (Vylkova et al., 2011). According to Rosado et al., the cell wall protein qid74, chitinase, protease, and glucose permease are among the Trichoderma genes that are affected by pH in various circumstances (Rosado et al., 2007). One of these is carbon deficiency, which occurs when there is little glucose (Vylkova et al., 2011). According to Rosado et al. (2007), the cell wall protein qid74, chitinase, protease, and glucose permease are among the Trichoderma genes that are affected by pH in various ways. PacC specifically lowers glucose permease and protease expression in T. harzianum while increasing chitinase and qid74 expression. Inhibitory metabolite accumulation is also prevented by PacC. Trichoderma does so by extracellular alkalization during sporulation, which raises the pH of the substrate. FA was likewise employed to modify soil pH.

On the other hand, soil samples from Eucalyptus spp. plantation soils contained low quantities of organic matter (1%), according to Shamsher et al. (2002). In comparison to the area where Eucalyptus spp. were absent, soil total N decreased as Eucalyptus grew, according to Tererai et al. (2014). Tererai et al. also provide an explanation for why the resistant litter and consequently poor breakdown rates of the leaves result in lower average soil total N, P, and K concentrations in Eucalyptus spp. plantation soils (Tererai et al., 2014). From this perspective, extracellular enzymes from Trichoderma, such as cellulases, are critical in decomposing organic polymers into simpler forms that can be transported inside the cell, and since Trichoderma is known to produce large amounts of cellulolytic and hemicellulolytic enzymes, it is attributable that inoculated treatments contain more cellulases than uninoculated treatments. This will increase the break-down of the cellulosic substrates in the Eucalyptus leaves, resulting in the production of more available nutrients that will promote fungal growth.

According to Lane et al. the expansion of Eucalyptus spp. plantations significantly reduces groundwater levels and decreases the amount of water available for irrigation on lands that were formerly used for arable crops or occupied by grass because of the plant’s profound and heavy root system and the properties of the soil (Lane et al., 2004) This tree creates draught concerns in the northern areas of Bangladesh since Eucalyptus plantations are currently so prevalent that they may be seen in great numbers on agricultural land, nearly every yard, office building, by the side of the road, and along railroad tracks (Supplementary Figure 3). Afforestation of exotic Eucalyptus spp. plantations is said to have a negative impact on the soil’s physical and chemical qualities as well as the biodiversity of the plant community, according to Wen et al. (2009). In our study, in condition AFW, rice yield was not affected by the dry condition due to the effect of Trichoderma application since it is evident that Trichoderma can alleviate the draught effects on plant growth by providing draught-resistant capacity to plants. Furthermore, S. indica colonization improves crop growth, yield, and drought tolerance. Under drought conditions, S. indica regulates phytohormone signaling, photosynthesis, wax biosynthesis, the cytoskeleton, and autophagy. Stress-induced ROS are detoxified by stimulating the host plant’s antioxidant system (Jangir et al., 2021). In our study, under AFW, TI04, and TI15 had the highest rates (percentages) of SI colonization, with 86.36 and 83.16, respectively. Likewise, water productivity (t ha⁻¹ cm⁻¹) values for TI04 and TI15 were greater under AFW, at 0.0763 and 0.0791, respectively. The increased mycorrhizae networking is an indicator of drought stress alleviation of rice plants and promotes the existing microbial community restoration.

This study’s findings revealed that manufacturing is an important stage in the development of a fungal inoculum, with high biosustainability and synergistic application of the inoculum, all of which contribute to the success of practical novel application. The inoculum’s efficacy in novel applications such as hazard mitigation and yield improvement in stressed conditions is a good indicator of its environmental usefulness. In this regard, the current study provides evidence for widespread use of this approach to reduce hazards and restore the agricultural ecosystem.

Overall, the findings demonstrate that Trichoderma could be grown using the nutrient deprivation technique at low pH to obtain biosustained spores. The biosustained spores had the enormous capacity to breakdown Eucalyptus leaves in vitro in a substantially shorter time than under normal circumstances. The biosustained spores and mycorrhizae were found to be a surprisingly effective combination in the field for decomposing Eucalyptus leaves, reducing water scarcity and low-pH risks created by Eucalyptus trees in crop production and restoring the existing soil ecology.

The original contributions presented in the study are included in the article/Supplementary material, further inquiries can be directed to the corresponding authors.

MGK, MA, and MFA: conceptualization of the research work, performer of the experimental research work, data collection, statistical analysis, manuscript writing, manuscript revision, and editing. JA-R: data collection, performer of the experimental research work, manuscript writing, reviewing, and editing. NMR: manuscript writing, reviewing, editing and, approval of the protocol. DM and PM: statistical analysis, manuscript writing, reviewing, and editing. YW: manuscript writing, reviewing and submission of the manuscript. All authors contributed to the article and approved the submitted version.

This study was supported by Apex Biofertilizers & Biopesticides Limited, Gobindaganj-5740, Gaibandha, Bangladesh, Apex Biotechnology Laboratory, Apex Holdings Ltd., East Chandora, Shafipur, Kaliakoir, Gazipur 1751, Bangladesh and the Initial Scientific Research Fund of Baotou Teachers’ College, Inner Mongolia, China (Grant no. BTTCRCQD2020-001).

MGK, MA, MFA, JA-R, and NMR were employed by Apex Biofertilizers and Biopesticides Limited. MA, NMR, and PM were employed by Apex Holdings Ltd.

The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

The authors declare that this study received funding from Apex Biofertilizers & Biopesticides Limited and Apex Holdings Ltd. The funder had the following involvement in the study: The funder provided overall guidance for the design of the study, conduct of the experiment, data collection, analysis, and interpretation, as well as the decision to submit this work for publication.

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.