Impact of biocontrol yeast clavispora lusitaniae 146 on the lemon microbiome

The use of biocontrol agents has been proposed as an effective alternative to reduce citrus decays for promoting sustainable agriculture based on organic fruit production. Among the different microbial biocontrol agents, Clavispora lusitaniae 146 stands out as it is able of effectively controlling green mold in lemons. Although there is growing recognition of the role that the microbiome plays in the health and physiology of many plant species, to date, the composition of the lemon microbiome is unknown, nor is the effect of yeast 146 on it. Thus, the aim of this research was to study the impacts of biocontrol yeast Clavispora lusitaneae 146 on the composition of the lemon microbiome. Lemons were harvested, and then divided into two treatments: untreated and treated lemons with biocontrol yeast C. lusitaneae 146. Fruits were then stored at room temperature for 7 days. DNA was extracted from a pool of 3 pieces of peel per sample, and used for PCR that amplified the bacterial hypervariable V3-V4 region of the 16S rRNA gene. Paired-end sequencing of amplicons was done on an Illumina MiSeq sequencer. To assess the effects of postharvest treatment and storage on the diversity of the lemon microbiome, we used a series of ANOVA and adonis (~PERMANOVA) models with Shannon diversity and community composition as the response variables, respectively. There was no statistically significant difference (KruskalWallies, p > 0.05) in bacterial diversity between the treated and untreated fruits. In this sense, the application of Clavispora lusitaneae 146 did not produce significant changes on bacterial communities of lemons during storage, including alpha diversity, community composition and structure. The bacterial community was dominated by roteobacteria,followed by Firmicutes and Actinobacteria. Specific bacterial taxa were only identified for untreated lemons: Methylobacteriaceae (Alphaproteobacteria) and unclassified bacteria, however in a low abundance. Here, we presented the first lemon microbiome and we showed that the microbial abundance, diversity, and community structures were not significantly different for both treatments, revealing that Clavispora lusitaniae 146 didn´t modify the native bacterial population of the fruit microbiome. The present study is part of larger project whose objectives are to define the complete lemon microbiome, assess the effects of the postharvest biocontrol agents on the composition of the lemon microbiome to develop a science-based strategy for manipulating this microbiome to prevent postharvest decay and physiological disorders.Fil: Rasuk, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Pisa, José Horacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Chacón, Florencia Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Pereyra, Martina María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Dib, Julian Rafael. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Microbiología; ArgentinaXVIII Congreso de la Sociedad Argentina de Microbiología GeneralChapadmalalArgentinaSociedad Argentina de Microbiología Genera

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

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

Amphibian skin bacteria display antifungal activity and induce plant defense mechanisms against Botrytis cinerea

Botrytis cinerea is the causal agent of gray mold, which affects a wide variety ofplant species. Chemical agents have been used to prevent the disease caused bythis pathogenic fungus. However, their toxicity and reduced efficacy haveencouraged the development of new biological control alternatives. Recentstudies have shown that bacteria isolated from amphibian skin displayantifungal activity against plant pathogens. However, the mechanisms bywhich these bacteria act to reduce the effects of B. cinerea are still unclear.From a diverse collection of amphibian skin bacteria, three proved effective ininhibiting the development of B. cinerea under in vitro conditions. Additionally,the individual application of each bacterium on the model plant Arabidopsisthaliana, Solanum lycopersicum and post-harvest blueberries significantlyreduced the disease caused by B. cinerea. To understand the effect of bacteriaon the host plant, we analyzed the transcriptomic profile of A. thaliana in thepresence of the bacterium C32I and the fungus B. cinerea, revealingtranscriptional regulation of defense-related hormonal pathways. Our studyshows that bacteria from the amphibian skin can counteract the activity of B.cinerea by regulating the plant transcriptional responses.Fil: Romero Contreras, Yordan J.. Centro de Ciencias Genomica ; Universidad Nacional Autonoma de Mexico;Fil: Gonzalez Serrano, Francisco. Centro de Ciencias Genomica ; Universidad Nacional Autonoma de Mexico;Fil: Formey, Damien. Centro de Ciencias Genomica ; Universidad Nacional Autonoma de Mexico;Fil: Aragón, Wendy. Universidad Autónoma de Chiapas; MéxicoFil: Chacón, Florencia Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Torres, Martha. Centro de Ciencias Genomica ; Universidad Nacional Autonoma de Mexico;Fil: Cevallos, Miguel Ángel. Centro de Ciencias Genomica ; Universidad Nacional Autonoma de Mexico;Fil: Dib, Julian Rafael. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Rebollar, Eria A.. Centro de Ciencias Genomica ; Universidad Nacional Autonoma de Mexico;Fil: Serrano, Mario. Centro de Ciencias Genomica ; Universidad Nacional Autonoma de Mexico