Mapping the colonization of a synthetic microbial community inoculum from sugarcane microbiome in soybean and maize plants

Author(s)

Natália de Brito Damasceno

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2018-09-13

Examining board members

Paulo Arruda; Juliana Velasco de Castro Oliveira; Fernando Dini Andreote; Lara Durães Sette; Sara Adrián López de Andrade

• Advisor: Rafael Soares Correa De Souza; Paulo Arruda

Abstract

This master's project was developed under the project "The Sugarcane Microbiome (Saccharome): A Key Element in Sustainability of an Energy Crop", which resulted in a detailed description of the diversity and relative abundance of microbial communities found in association with sugarcane along plant development. At a second moment, we constructed and annotated a collection of microorganisms representative of sugarcane core microbiome. The identification of bacterial groups present in the collection allowed cross-referencing this information with data from sugarcane microbiome description concerning abundance and diversity. As a result, it was possible to elaborate a synthetic community composed of 17 isolates, which represents the most abundant bacterial groups found in sugarcane. Preliminary results in maize showed that the synthetic inoculum efficiently promotes plant growth. By sequencing rRNA 16S gene, it was possible to map the colonization pattern of these bacterial groups in endophytic and exophytic compartments of root, stem and leaves of inoculated maize plants. Among 27 bacteria present in the inoculum, 10 groups were highly efficient in colonizing plant tissues, resulting in alterations in the natural maize microbiota composition and becoming predominant mainly in the root and stem. In this work, we evaluated the impact of the same synthetic community, previously validated in maize, in soybean plants in order to verify the trans specificity of the synthetic inoculum in a plant species phylogenetically distant from sugarcane and maize. As the synthetic community is composed of microbial isolates that possibly contains more than one microorganism stored together, we seek to uncover bacterial groups in association with soybean and fungal groups in association with both models that are potentially involved in colonizing plant tissues. Soybean inoculated plants showed a significant increase in their biomass and roots and leaf areas of up to 1.6 fold when compared to uninoculated plants. By sequencing rRNA 16S gene, we accessed bacterial groups from the synthetic inoculum in the roots, stem and leaves of inoculated and uninoculated soybean plants. Members of the synthetic community did not colonize plant tissues very efficiently, however, the presence of the inoculum promoted alterations in the natural microbiota found in association with this plant. Comamonadaceae, Caulobacteraceae, Rhizobiaceae, Sphingobacteriaceae, Burkholderiaceae and Xanthomonadaceae families are the most representative groups identified in association with inoculated and uninoculated soybean plants. Together, these results suggest that the synthetic community, initially isolated from sugarcane, has a plasticity in colonizing plant tissues and promote plant growth of phylogenetically distant plant species like maize and soybean, two representatives of mono and dicotyledonous. The mechanisms directly involved in these effects are still unknown, but we believe that these functions can have been select during the co-evolution of microbiota/plant interactions and can be relate to the higher availability of nutrients naturally produced by plants, by genes that were selected/enriched in these specific bacteria (AU)

• FAPESP's process: 16/23425-5 - Mapping the colonization of a synthetic microbial community inoculum from sugarcane microbiome in maize and soybean plants
• Grantee: Natália de Brito Damasceno
• Support Opportunities: Scholarships in Brazil - Master