Molecular mechanisms related to the interaction between endophytic microorganisms and the host plant

Abstract

In recent years, the interest in endophytic microorganisms as an important source of new species and potential use in biological control and production of metabolites with different biological activities has increasing. Despite the discovery of new compounds from these microorganisms, there is a gap between the production os certains compounds and the knowledge of the biosynthetic pathways, also role of these compounds in the endophytes-plant interaction is stil understood. In previous projects a collection of endophytic microorganisms was organized (Proc. FAPESP 2003/14143-3) and genes associated with the synthesis of secondary metabolites (Procs. FAPESP 2010/08286-2; 2008/52407-9), interaction with the host plant (Proc. FAPESP 2010/07594-5) and biological control (Procs. FAPESP 2008/52407-9) were identified in the fungus Epicoccum nigrum P16 and bacteria Burkholderia seminalis TC3.4.2R3 and Methylobacterium mesophilicum SR1.6/6. In these projects, the genomes of E. nigrum P16 and M. mesophilicum SR1.6/6 were sequenced and have been assembled and annotated, allowing the studies of genes and possible metabolic pathways associated with endophytes-plant interaction. The strains B. seminalis TC3.4.2R3 and E. nigrum P16 were also used to generate a mutant library with approximately 1200 and 2100 mutans, respectively, which has been used for the identification of genes associated with microbial interactions. Therefore, the aims of the present project are i) to evaluate the transcriptome (RNA-seq) of E. nigrum P16, B. seminalis TC3.4.2R3 and M. mesophilicum SR1.6/6 in different growth conditions; ii) determine the genes expressed at different stages of microbial interaction; iii) confirm the association of genes/operons with the synthesis of antimicrobial compounds and colonization of the host plant by gene knockout/complementation; iv) cloning and express genes that encode peptides involved in the control of pathogens; v) identify new compounds produced by wild strain and absent B. seminalis and E. nigrum mutants. Thus, this project will contribute to a better understanding of many biological processes associated to microbial interaction, mainly related to plant colonization, biological control of phytopathogens and synthesis of bioactive molecules by endophytic microorganisms. This study will allow not only the development of biological control strategies based on endophytes, but also the organization of a gene library that may be used in many biotechnological applications, such as synthesis of biomolecules, generation of recombinant microorganisms and genetically modified plants. (AU)