Although the importance of plant-associated microorganisms for plant growth and health was getting more recognition recently, the role of seed-associated microorganisms, and especially seed endophytic bacteria, still is underestimated. Nevertheless, these associations could be beneficial for germination and seedling establishment as seed endophytic bacteria are already present in these very early plant growth stages. In this work, the presence of endophytic bacteria in the seeds of Anadenanthera colubrina var. cebil (Vell.) Brenan, a Fabaceae tree of South America, has been demonstrated using culture-dependent, culture-independent approaches and FISH analysis. Culture-dependent approach, based on the isolation of cultivable bacteria and subsequent identification by analysis of their 16S rDNA sequences, allowed the identification of species closely related to Staphylococcus and Methylobacter. The culture-independent approach, based on the high-throughput sequencing 16S rDNA amplified from seed metagenomic DNA, confirmed the results of the culture dependent approach. This analysis also identified Actinomyces, Pseudomonas and Clostridium genera. Fluorescence in situ Hybridization coupled with Confocal Laser Scanning Microscopy (FISH-CLSM) confirmed the presence of bacteria belonging to both Alphaproteobacteria and Firmicutes Phyla in seed cryosections. The bacteria were arranged as single cells or small colonies with up to ten cells and colonized the outer seed coat as well as the internal tissues. All these results demonstrate for the first time that typical Phyla of the root- and leaf-microbiota, such as ? Proteobacteria, Firmicutes and Actinobacteria, are present in the seeds of Anadenanthera colubrina.
The seed microbiota of Anadenanthera colubrina
M Ciaccio;
2015
Abstract
Although the importance of plant-associated microorganisms for plant growth and health was getting more recognition recently, the role of seed-associated microorganisms, and especially seed endophytic bacteria, still is underestimated. Nevertheless, these associations could be beneficial for germination and seedling establishment as seed endophytic bacteria are already present in these very early plant growth stages. In this work, the presence of endophytic bacteria in the seeds of Anadenanthera colubrina var. cebil (Vell.) Brenan, a Fabaceae tree of South America, has been demonstrated using culture-dependent, culture-independent approaches and FISH analysis. Culture-dependent approach, based on the isolation of cultivable bacteria and subsequent identification by analysis of their 16S rDNA sequences, allowed the identification of species closely related to Staphylococcus and Methylobacter. The culture-independent approach, based on the high-throughput sequencing 16S rDNA amplified from seed metagenomic DNA, confirmed the results of the culture dependent approach. This analysis also identified Actinomyces, Pseudomonas and Clostridium genera. Fluorescence in situ Hybridization coupled with Confocal Laser Scanning Microscopy (FISH-CLSM) confirmed the presence of bacteria belonging to both Alphaproteobacteria and Firmicutes Phyla in seed cryosections. The bacteria were arranged as single cells or small colonies with up to ten cells and colonized the outer seed coat as well as the internal tissues. All these results demonstrate for the first time that typical Phyla of the root- and leaf-microbiota, such as ? Proteobacteria, Firmicutes and Actinobacteria, are present in the seeds of Anadenanthera colubrina.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
