Native Cultivable Bacteria from the Blueberry Microbiome as Novel Potential Biocontrol Agents

Abstract

Blueberry production is affected by fungal postharvest pathogens, including Botrytis cinerea and Alternaria alternata, the causative agents of gray mold disease and Alternaria rot, respectively. Biocontrol agents adapted to blueberries and local environments are not known to date. Here, we report on the search for and the identification of cultivable blueberry epiphytic bacteria with the potential to combat the aforementioned fungi. Native, blueberry-borne bacterial strains were isolated from a plantation in Tucumán, Argentina and classified based on 16S rRNA gene sequences. Antagonistic activities directed at B. cinerea and A. alternata were studied in vitro and in vivo. The 22 bacterial strains obtained could be attributed to eleven different genera: Rosenbergiella, Fictibacillus, Bacillus, Pseudomonas, Microbacterium, Asaia, Acinetobacter, Curtobacterium, Serratia, Sphingomonas and Xylophilus. Three strains displaying antagonistic impacts on the fungal pathogens were identified as Bacillus velezensis (BA3 and BA4) and Asaia spathodeae (BMEF1). These strains are candidates for biological control agents of local blueberry production and might provide a basis for the development of eco-friendly, sustainable alternatives to synthetic pesticides.

A quantitative survey of the blueberry (Vacciniumspp.) nectar microbiome: variation between cultivars, locations, and farm management approaches

“…As expected, nectar specialists such as species of Rosenbergiella, which has been previously isolated from blueberry flowers (Chacón et al 2022), and members of the genera Metschnikowia, Acinetobacter, and Neokomagataea (Álvarez-Pérez and Herrera 2013; de Vega et al 2021;Vannette et al 2021) were frequently detected. Additionally, insect-associated microbes were identified, like Acinetobacter apis, isolated from the digestive tract of honey bees (Kim et al 2014), and Erwinia aphidicola, isolated from the gut of aphids (Harada et al 1997).…”

“…In turn, microbial modulations to floral attractiveness can affect plant reproduction by increasing or decreasing visitation to flowers (Vannette et al 2013;Schaeffer and Irwin 2014;Yang et al 2019;de Vega et al 2022). Nectar-and flower-inhabiting microbes can also have direct impacts on plant health either as pathogens (Bubán, Orosz-Kovács, Farkas 2003;Ngugi and Scherm 2006) or as protective species that can prevent or reduce disease (Pusey, Stockwell and Mazzola 2009;Chacón et al 2022;Crowley-Gall et al 2022).…”

“…2019; de Vega et al 2022). Nectar– and flower-inhabiting microbes can also have direct impacts on plant health either as pathogens (Bubán, Orosz-Kovács, Farkas 2003; Ngugi and Scherm 2006) or as protective species that can prevent or reduce disease (Pusey, Stockwell and Mazzola 2009; Chacón et al . 2022; Crowley-Gall et al .…”

“…Blueberry is a highly nutritious pollinator-dependent crop that generates over $1 billion annually in the US (U.S. National Agricultural Statistics Service 2021). To date, only one study has reported microbes inhabiting the blueberry anthosphere (Chacón et al . 2022), with the aim of isolating bacteria with biocontrol potential from whole blueberry flowers and fruit, rather than providing a systematic survey of microbial incidence and abundance in nectar.…”

Gene expression and genetic divergence in oak species highlight adaptive genes to soil water constraints

“…In the MetaMetaDB [19], hits corresponding to Xylophilus ampelinus 16S (97% identity) appear in a variety of ecosystems (beetle: 22.46%, soil: 17.67%, rhizosphere: 13.01%, marine: 8.34%, freshwater: 6.98%, root: 6.88%, human lung: 5.79%, ant fungus garden: 5.72%, human skin: 5.08%, hydrocarbon: 4.53% bovine gut: 3.52%). The bacterium has also been recently isolated from the microbiota of blueberry [20], indicating that its actual occurrence in the environment is probably underestimated.…”