Culture-Independent Characterization of Citrus Rhizospheric Bacterial and Fungal Microbiota from Piura, Peru

The “limón sutil” (Citrus aurantifolia) has been widely cultivated and well established for many years in Piura, northwestern Peru, because of its exceptional climate and soil conditions. However, decline and death of C. aurantifolia trees caused by different phytopathogens remain a common problem which has been observed in the last decades. It is known that the microbiota of soil plays an important role with their host and could be the starting point to understand the causes of citrus decline. In this study, we identified through culture-independent methods the bacterial and fungal microbiota associated to C. aurantifolia, C. jambhiri and C. volkameriana rhizospheres in the main areas of Piura. By using a 16S rRNA and ITS-metabarcoding analysis, we evaluated the taxonomic diversity between healthy trees and with decline symptoms and how this diversity could influence the health status of citrus trees. More than 600 and 200 bacterial and fungal ASVs were identified, respectively. Our metabarcoding analysis was able to identify Proteobacteria, Cyanobacteria, Firmicutes, Bacteroidota and Acidobacteriota prokaryotic phyla, while fungal phyla included Ascomycota, Basidiomycota and Glomeromycota. In addition, there were differences between microbial diversity indices in rhizospheres evaluated. Finally, bacterial and fungal genera were shared among the different citrus rhizospheres. These results have allowed us to obtain a preliminary identification of microbiota in the citrus rhizospheres of healthy trees and with decline symptoms.