Investigation of ubiquitous endophytic microbiota in \axenic\ microplants.

Author(s)

Natalia Pimentel Esposito Polesi

• Document type: Master's Dissertation
• Press: Piracicaba.
• Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC)
• Defense date: 2010-08-30

Examining board members

Marcilio de Almeida; Welington Luiz de Araujo; Francisco Andre Ossamu Tanaka

• Advisor: Marcilio de Almeida

Abstract

Tissue culture has been an important tool widely used for various purposes, among them the micropropagation has been highlighted due to the rapid production of healthy seedlings in a small space. Within this context, the term axenic plant has been distributed as an ideal to be achieved in this technique, which the search based on numerous methods that effectively eliminate any contamination that may eventually grow into the culture medium. However, it is seen that the conception of contamination in tissue culture should be reviewed as well as axenic plants, because several studies have shown that even in asymptomatic microplants considered axenic, there is an ubiquitous and that the endophytic community mostly plays a fundamental role in the establishment, development and acclimatization of cultures, therefore, beneficial microorganisms that should be preserved in vitro. Thus, this study aimed to investigate the endophytic microbiota present in several species of micro asymptomatic considered \"axenic\" regardless of their protocol for in vitro culture, location, method of micropropagation and manipulation. For this purpose, were used asymptomatic microplants in multiplication stage by more than one year, from three different laboratories, and were submitted to characterization by histochemistry tests, ultrastructural analysis, isolation in different culture medium by two methods (grinding and fragmentation), molecular analyses using the extraction of total genomic DNA and PCR-DGGE, in addition to extracting and sequencing the DNA of the isolates obtained. The results obtained by the isolation, molecular and ultrastructural analysis, showed the presence of an endophytic community colonizing the tissues of different species of microplants, from three different laboratories. Thus, it was concluded that the inexistence of axenic plants should be considered in future as a positive aspect in the tissue culture, since this endophytic community can give agronomical traits to different crop species. (AU)

• FAPESP's process: 08/07535-9 - Investigation of ubiquitous presence of endophytic microrganisms from axenic microplants
• Grantee: Natalia Pimentel Esposito Polesi
• Support Opportunities: Scholarships in Brazil - Master