8.6 Conclusion
Endophytic actinobacteria have been isolated from several plant species and
inoculated onto different target agricultural crops often resulting in enhanced plant
performance. Improvements in isolation and identification methods are yielding
new isolates with plant growth promoting traits and showing that endophytic
actinobacteria are amongst the predominant bacterial phyla inside plants, including
agriculturally important crops. The use of endophytic actinobacteria as microbial
inoculants in agriculture offers considerable advantages when compared with that of
rhizobacteria, since competition effects are greatly reduced in the colonization of
the internal tissues of the plant, thus increasing the chances of survival, growth, and
effectiveness of the endophytic inoculants. Endophytic actinobacteria are able to
enhance the establishment, growth, development, and health of agricultural crops
directly via production/secretion of various regulatory chemicals and indirectly via
inhibition of phytopathogens. Thus, endophytic actinobacteria hold the prospect of
reducing the input of chemical fertilizers and pesticides and their inoculation can be
regarded as an environmentally friendly approach in agriculture. There is, therefore,
great potential in using endophytic actinobacteria as biotechnological tools for
sustainable agricultural applications.
Acknowledgements M.F. Carvalho acknowledges Investigator FCT program supported by
Fundação para a Ciência e a Tecnologia (FCT), Fundo Social Europeu (FSE) and Programa
Operacional Potencial Humano. R.S. Oliveira and Y. Ma thank the support of FCT through the
research grants SFRH/BPD/85008/2012 and SFRH/BPD/76028/2011, FSE and Programa
Operacional do Capital Humano (POCH). This work was partlyfinanced by Portuguese national
funds through Programa Operacional Competitividade e Internacionalização (POCI), Project 3599
- Promover a Produção Científica e Desenvolvimento Tecnológico e a Constituição de Redes
Temáticas (3599-PPCDT) and Fundo Europeu de Desenvolvimento Regional (FEDER) under
Project POCI-01-0145-FEDER-016801 and by FCT under Project PTDC/AGR-TEC/1140/2014.
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