In recent years, the adoption of sustainable pest management strategies has increased interest in the utilization of biopesticides, with a focus on harnessing beneficial microorganisms. Among these, lipopeptides, such as surfactins, iturins, and fengycins produced by the genus Bacillus, have gained significant attention due to their multifaceted biocontrol mechanisms and wide-ranging inhibitory effects. This review aims to address the regulation, biosynthesis, and production of three main lipopeptide families secreted by the genus Bacillus, as well as the identification and quantification analysis used to date, through the omic tools approach. The three families have been identified as key contributors to the biocontrol abilities of these bacteria, with their broad-spectrum activity making them valuable tools in integrated pest management approaches that aim to reduce reliance on chemical pesticides use while maintaining crop health and productivity.

El género Bacillus presenta una amplia diversidad metabólica asociada a su prevalencia en diversos ecosistemas. En la actualidad, una de las características más estudiadas de este género bacteriano es su capacidad para disminuir la incidencia de enfermedades en cultivos agrícolas, debido a la represión directa o indirecta del crecimiento de los agentes causales dichas enfermedades. Entre los mecanismos más estudiados en el control biológico de cepas del género Bacillus contra agentes fito-patógenos destacan los lipopéptidos, tales como surfactinas, iturinas y fengicinas, los cuales son compuestos de bajo peso molecular con características anfifílicas que proporcionan protección a las plantas tanto en condiciones previas como posteriores a la cosecha. Los lipopéptidos pueden antagonizar directamente a los agentes fito-patógenos y inducir estrategias de resistencia sistémica en las plantas asociadas. Sin embargo, el amplio uso de lipopéptidos en el sector agrícola, farmacéutico, o alimentario depende del desarrollo de procesos analíticos eficientes y económicos para la extracción, identificación, y cuantificación de dichos compuestos bioactivos. Este ensayo presenta un análisis sobre diversos procedimientos analíticos empleados para la extracción, e identificación cualitativa y cuantitativa de estos metabolitos.

Strain TSO9 was isolated from a commercial field of wheat (Triticum turgidum L. subsp. durum) located in the Yaqui, Valley, Mexico. Here, the genome of this strain was sequenced, obtaining a total of 5,248,515 bp; 38.0% G + C content; 1,186,514 bp N50; and 2 L50. Based on the 16S rRNA gene sequencing, strain TSO9 was affiliated with the genus Priestia. The genome annotation of Priestia sp. TSO9 contains a total of 147 RNAs, 128 tRNAs, 1 tmRNA, and 5512 coding DNA sequences (CDS) distributed into 332 subsystems, where CDS associated with agricultural purposes were identified, such as (i) virulence, disease, and defense (57 CDS) (i.e., resistance to antibiotics and toxic compounds (34 CDS), invasion and intracellular resistance (12 CDS), and bacteriocins and ribosomally synthesized antibacterial peptides (10 CDS)), (ii) iron acquisition and metabolism (36 CDS), and (iii) secondary metabolism (4 CDS), i.e., auxin biosynthesis. In addition, subsystems related to the viability of an active ingredient for agricultural bioproducts were identified, such as (i) stress response (65 CDS). These genomic traits are correlated with the metabolic background of this strain, and its positive effects on wheat growth regulation reported in this work. Thus, further investigations of Priestia sp. TSO9 are necessary to complement findings regarding its application in agroecosystems to increase wheat yield sustainably.

Fungal pathogens are the main causal agents of postharvest diseases of fruits and vegetables. To prevent this problem and avoid the use of harmful chemical fungicides, safer and greener alternatives have been sought. One of these alternatives is the use of plant-growth-promoting bacteria (PGPB). In this study, we evaluated in vitro four well-known PGPB strains (Pseudomonas fluorescens UM270, Bacillus toyonensis COPE52, Bacillus sp. E25, and Bacillus thuringiensis CR71) for their biocontrol potential against nineteen postharvest fungal pathogens. In vivo assays were also performed, and bacterial cells were inoculated on harvested strawberries and grapes with the pathogens Botrytis cinerea, Alternaria alternata, and Fusarium brachygibbosum to evaluate loss of firmness and disease incidence. Our results show that the four strains antagonized fungi in direct and indirect confrontation assays. Stronger antagonism was observed by the action of diffusible metabolites (DMs) compared to volatile organic compound (VOC) activity. All PGPB significantly improved the fruit firmness and reduced disease incidence caused by the fungal pathogens tested. However, strain UM270 showed excellent biocontrol activity, reducing the disease incidence of Fusarium brachygibbosum, Botrytis cinerea, and Alternaria alternata on strawberry fruits by 60%, 55%, and 65%, respectively. Diffusible antifungals and VOCs such as 2,4-diacetyl phloroglucinol, siderophores, auxins, fengycins, and N, N-dimethyl-hexadecyl amine, among others, might be responsible for the beneficial activities observed. These results suggest excellent biocontrol activities to inhibit postharvest pathogenic fungi and improve harvested fruit quality.

Jalapeño peppers (Capsicum annuum var. Jalapeño) represent one of the most important crops in Mexico. However, many plant diseases, such as wilt caused by strains of the genus Fusarium, reduce its yield. A sustainable alternative to control diseases is the use of biological control agents (BCAs), for example, beneficial microorganisms such as strains of the genus Bacillus. This study aims to analyze the potential use of B. cabrialesii subsp. tritici TSO2^T as a BCA and elucidate its potential modes of action against Fusarium strains causing wilt in Jalapeño peppers. For this, symptomatic samples were collected in a commercial field in the Yaqui Valley, Mexico. Six Fusarium isolates were morphologically and molecularly characterized. After pathogenicity tests, F. languescens CE2 was found to be pathogenic. In screening assays for biocontrol bacteria, strain TSO2^T, which was isolated from soil in a wheat commercial field under an organic production system and preserved in the Culture Collection of Native Soil and Endophytic Microorganisms (COLMENA), had the best biocontrol effect against CE2, and its cell-free filtrate reduced mycelial growth by 30.95%. Genome mining (antiSMASH) of strain TSO2^T allows us to identify gene clusters associated with biocontrol, such as fengycin, surfactin, bacillibactin, bacilysin, bacillaene, subtilosin A, and sporulation killing factor, which codify to antimicrobial metabolites and are associated with swarming motility of the studied beneficial strain. These results demonstrate the effectiveness of B. cabrialesii subsp. tritici TSO2^T as a potential BCA for the control of Fusarium wilt, through competition and a complex of antifungal metabolites, which still need to be validated through metabolomic analysis. This study highlights the importance of the use of integrative genomic and bioactivity-guided methodologies in understanding biocontrol pathosystems.

Wheat production worldwide faces numerous challenges linked to climate change, exponential population growth, nutrient depletion in agricultural soils, and the increasing threat of phytopathogen occurrence. The application of beneficial microorganisms is a promising strategy for crop management as it favorizes nutrient uptake, improves soil fertility, and increases plant resilience. Therefore, this approach facilitates the transition to more sustainable agricultural practices while reducing the dependence on agrochemicals. The valuable beneficial impacts of bioinoculant application include the enrichment of agricultural soils’ ecosystems by restoring microbial populations and interactions that have been lost through the years due to decades of intensive agricultural practices and the massive application of pesticides. Furthermore, beneficial microorganisms constitute a remarkable tool for combating biotic threats, specifically fungal pathogens, whose proliferation and emergence are predicted to increase due to global warming. To optimize their beneficial impact, bioinoculant development requires an extensive study of microbial interactions with plants and their surrounding ecosystem, to improve their composition, mode of action, and stability through application. The use of innovative tools, such as omic sciences, facilitates the elucidation of these mechanisms. Finally, bioprospection and bioformulation must be consciously executed to guarantee the application and persistence of adapted microorganisms and/or their bioactive molecules.