Synthetic herbicides such as glyphosate and 2,4-D are widely used in agriculture but can negatively impact non-target organisms, including microorganisms essential for ecological balance. Yeasts associated with pollinating insects play crucial roles in plant–insect interactions, yet their responses to herbicides remain understudied. This study aimed to evaluate the capacity of yeasts isolated from bees and beetles to produce indole-3-acetic acid (IAA), a plant-growth-promoting hormone, as well as their ability to tolerate or degrade glyphosate (in the commercial herbicide Zapp QI 620^®) and 2,4-D (in the commercial Aminol 806^®). Seven yeast strains were isolated from insects, identified via ITS sequencing, and assessed for IAA production in YPD medium. Growth assays were conducted under varying herbicide concentrations, and 2,4-D degradation was analyzed using high-performance liquid chromatography. All strains produced IAA, with Papiliotrema siamensis CHAP-239 exhibiting the highest yield (4.17 mg/L). Glyphosate completely inhibited growth in all strains, while 2,4-D showed dose-dependent effects, with four strains tolerating lower concentrations. Notably, Meyerozyma caribbica CHAP-248 degraded up to 46% of 2,4-D at 6.045 g/L. These findings highlight the ecological risks herbicides pose to beneficial yeasts and suggest the potential of certain strains for bioremediation in herbicide-contaminated environments. Overall, the study underscores the importance of preserving microbial biodiversity in the context of sustainable agriculture.

Plant-associated yeasts play significant ecological roles within the microbiomes of soils and pollinating insects. In previous studies, we have shown that yeasts can assist pollinators in locating nectar, which is crucial for their nutrition and the reproduction of many angiosperms. Additionally, in soil, yeasts can also act as plant growth promoters. Given the importance of yeasts for plant development, this review first explores the biochemical processes underlying the ecological role of these microorganisms in soil, insects, and in direct association with plants. Based on this premise, we discuss the influence of these relationships on agricultural production, the biological mechanisms through which pesticides negatively affect yeast cells, and how these microorganisms can tolerate widely used agrochemicals. Finally, we address key studies in the literature that support the potential of these microorganisms as bioremediation agents. In this context, we emphasize different experiences with both indigenous and genetically engineered yeasts, which may display enzymes in their surfaces that convert pesticides into less harmful or nontoxic molecules. Our review indicates that yeasts can be effectively harnessed in organic agriculture to promote plant growth and bioremediate contaminated soil or food.

Plant-associated yeasts can also be part of soils’ and pollinating-insects’ microbiomes, where they play significant ecological roles. Indeed, in previous studies, we have shown that yeasts may help pollinators find nectar, which is crucial for their nutrition and for the reproduction of many angiosperms, and, in the soil, can act as plant-growth promoters. Given the importance of yeasts for plant development, in this review, we first delve deep into the biochemical processes behind the ecological role of these microorganisms in soil, insects, and in direct association with plants. Based on this premise, we discuss the influence of this relationship on agricultural production and the possible effects of pesticide use on the yeast microbiota. Finally, we address the most relevant studies in the literature that support the potential of these microorganisms (either indigenous or genetically engineered) as bioremediation agents for soils and foods contaminated by pesticides. Our review indicates that yeasts can be satisfactorily employed in organic agriculture to increase plant growth or bioremediate contaminated soil or food.

The study of growth-promoting microorganisms is vital due to their potential for developing agricultural technologies that enhance the sustainability of production systems. The identification, isolation, and production of these organisms can contribute to the generating new, high-value agricultural bioinputs. Therefore, this research aimed to evaluate the effect of treating vegetable seeds (carrot and cauliflower) with a yeast cell culture on seed quality and seedling production. The yeast strain used in the experiments (CHAP-208), isolated from Senna macranthera flowers, was identified as Rhodotorula sp. During cultivation, it produced ~ 2.8 mg/L of indole acetic acid (IAA). Subsequent germination and seedling growth experiments were conducted under laboratory conditions for both carrot and cauliflower, followed by seedling production trials in an agricultural greenhouse for cauliflower. Imbibing carrot seeds for 2 h in the Rhodotorula sp. CHAP-208 cell suspension enhenced seedling development under laboratory conditions. Soaking cauliflower seeds did not affect germination but increased plant emergence rates and root length in the greenhouse environment. This effect may be linked to the auxin-production capacity of Rhodotorula sp. CHAP-208, marking the first report of a yeast isolated from S. macranthera flowers with high plant growth-promoting activity. These findings suggest that Rhodotorula sp. CHAP-208 is a promising bioinoculant for promoting plant growth. Future studies should quantify IAA levels before and after seed soaking, as well as in samples from the resulting seedlings and plants.

As leveduras, fungos unicelulares amplamente empregados na indústria de alimentos e bebidas, estão desempenhando um papel cada vez mais relevante na síntese de metabólitos naturais para fins biotecnológicos. Esses metabólitos, de natureza diversificada, encontram aplicações em diversos setores, particularmente na área da saúde, e abrangem uma variedade de moléculas com atividades biológicas vantajosas, tais como antimicrobiana, antioxidante, anti-inflamatória e antineoplásica. Nesse contexto, este capítulo visa explorar as leveduras que ocorrem naturalmente como produtoras de metabólitos bioativos, explanando os tipos de compostos que elas produzem e destacando suas potenciais aplicações em benefício da saúde humana. Também são discutidas as abordagens biotecnológicas mais promissoras para a produção de metabólitos terapêuticos a partir de leveduras, que incluem (1) o isolamento de leveduras e a otimização de processos de fermentação e extração dos compostos, (2) a engenharia genética de leveduras para melhorar a produção desses compostos, e (3) testes de citotoxicidade e avaliação do potencial terapêutico dos metabólitos de leveduras. Em síntese, as leveduras desempenham um papel crucial na produção de metabólitos naturais com múltiplas propriedades benéficas para a saúde, e este capítulo investiga as estratégias e avanços biotecnológicos que estão impulsionando o potencial terapêutico desses compostos.