Eucalyptus plantations offer a cost-effective and renewable source of raw material. There is substantial interest in improving forestry production, especially through sustainable strategies such as the use of plant growth-promoting bacteria. However, little is known about Eucalyptus microbiology. In this study, the endophytic bacterial community was assessed in Eucalyptus urograndis roots using culture-dependent and culture-independent techniques with plants grown under different conditions. Three phyla accounted for approximately 95% of the community, with Actinobacteria corresponding to approximately 59%. This contrasts with previous studies in which Actinobacteria accounted for only 5 to 10%. Our data also revealed a high diversity of bacteria, with 359 different genera but a high level of dominance. Six genera, Mycobacterium, Bradyrhizobium, Streptomyces, Bacillus, Actinospica, and Burkholderia, accounted for more than 50% of the classified sequences. We observed a significant influence of the treatments on some genera, causing changes in the bacterial community structure. The obtained data also suggest that Eucalyptus may benefit from biological nitrogen fixation, with many abundant genera being closely related to nitrogen-fixing bacteria. Using N-depleted media, we also cultured 95 bacterial isolates, of which 24 tested positive for the nifH gene and were able to maintain growth without any N source in the medium.
This is a preview of subscription content, log in to check access.
Compliance with Ethical Standards
This work received funding from the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) and Fundação de Amparo à Pesquisa do Estado de São Paulo (Fapesp).
Conflict of Interests
The authors have declared that no competing interests exist.
INDUFOR (2012) Strategic review on the future of forest plantationsGoogle Scholar
Laclau J-P, Almeida JCR, Goncalves JLM, et al. (2008) Influence of nitrogen and potassium fertilization on leaf lifespan and allocation of above-ground growth in eucalyptus plantations Tree Physiol. 29:111–124. doi:10.1093/treephys/tpn010CrossRefPubMedGoogle Scholar
Stape JL, Binkley D, Ryan MG, et al. (2010) The Brazil Eucalyptus potential productivity project: influence of water, nutrients and stand uniformity on wood production For. Ecol. Manag. 259:1684–1694. doi:10.1016/j.foreco.2010.01.012CrossRefGoogle Scholar
Goncalves JLM, Stape JL, Laclau JP, et al. (2008) Assessing the effects of early silvicultural management on long-term site productivity of fast-growing eucalypt plantations: the Brazilian experience South For 70:105–118. doi:10.2989/SOUTH.FOR.2008.70.2.6.534CrossRefGoogle Scholar
Baligar VC, Fageria NK (2015) Nutrient use efficiency in plants: an overview. In: Nutr. Use Effic. from Basics to Adv. Springer India, New Delhi, pp 1–14. doi:10.1007/978-81-322-2169-2_1
Binkley D, Dunkin KA, DeBell D, Ryan MG (1992) Production and nutrient cycling in mixed plantations of Eucalyptus and Albizia in Hawaii For. Sci. 38:393–408Google Scholar
Balieiro FC, Franco AA, Fontes RLF, et al. (2002) Accumulation and distribution of aboveground biomass and nutrients under pure and mixed stands of Pseudosamanea guachapele Dugand and Eucalyptus grandis W. Hill ex Maiden J Plant Nutr 25:2639–2654CrossRefGoogle Scholar
Forrester DI, Cowie AL, Bauhus J, et al. (2006) Effects of changing the supply of nitrogen and phosphorus on growth and interactions between Eucalyptus globulus and Acacia mearnsiiin a pot trial Plant Soil 280:267–277. doi:10.1007/s11104-005-3228-xCrossRefGoogle Scholar
Araújo WL, Maccheroni W, Aguilar-Vildoso CI, et al. (2001) Variability and interactions between endophytic bacteria and fungi isolated from leaf tissues of citrus rootstocks Can. J. Microbiol. 47:229–236. doi:10.1139/w00-146CrossRefPubMedGoogle Scholar
Cole JR, Wang Q, Cardenas E, et al. (2009) The Ribosomal database project: improved alignments and new tools for rRNA analysis Nucleic Acids Res. 37:141–145. doi:10.1093/nar/gkn879CrossRefGoogle Scholar
Schloss PD, Westcott SL, Ryabin T, et al (2009) Introducing mothur: open-source, platform-independent, community-supported software for describing and comparing microbial communities. Appl Environ Microbiol 75:7537–7541. doi:10.1128/AEM.01541-09
Biondini ME, Bonham CD, Redente EF (1985) Secondary successional patterns in a sagebrush (Artemisia tridentata) community as they relate to soil disturbance and soil biological activity Vegetatio 60:25–36. doi:10.1007/BF00053909CrossRefGoogle Scholar
Dufrene M, Legendre P (1997) Species assemblages and indicator species: the need for a flexible asymmetrical approach Ecol. Monogr. 67:345–366. doi:10.2307/2963459CrossRefGoogle Scholar
Atlas RM (2005) Handbook of media for environmental microbiology, 2nd ed. CRC Press, Boca RatonGoogle Scholar
Poly F, Monrozier LJ, Bally R (2001) Improvement in the RFLP procedure for studying the diversity of nifH genes in communities of nitrogen fixers in soil Res. Microbiol. 152:95–103CrossRefPubMedGoogle Scholar
Lane D (1991) Nucleic acid techniques in bacterial systematics. In: Stackebrandt E, Goodfellow M (eds) 16S/23S rRNA Seq. John Wiley and Sons, New York, pp. 115–175Google Scholar
Hall T (1999) BioEdit: a user-friendly biological sequence alignment editor and analysis program for Windows 95/98/NT Nucleic Acids Symp. Ser. 41:95–98Google Scholar
Manter DK, Delgado JA, Holm DG, Stong RA (2010) Pyrosequencing reveals a highly diverse and cultivar-specific bacterial endophyte community in potato roots Microb. Ecol.:157–166. doi:10.1007/s00248-010-9658-x
Miguel PSB, de Oliveira MNV, Delvaux JC, et al. (2016) Diversity and distribution of the endophytic bacterial community at different stages of Eucalyptus growth Anton Leeuw Int J Gen Mol Microbiol 109:755–771. doi:10.1007/s10482-016-0676-7CrossRefGoogle Scholar
Silva EV, Gonçalves JL, Coelho SR, et al. (2009) Dynamics of fine root distribution after establishment of monospecific and mixed-species plantations of Eucalyptus grandis and Acacia mangium Plant Soil 325:305–318. doi:10.1007/s11104-009-9980-6CrossRefGoogle Scholar
Santos FM, Chaer GM, Diniz AR, de Balieiro FC (2017) Nutrient cycling over five years of mixed-species plantations of Eucalyptus and Acacia on a sandy tropical soil For. Ecol. Manag. 384:110–121. doi:10.1016/j.foreco.2016.10.041CrossRefGoogle Scholar
Paula RR, Bouillet J-P, Ocheuze Trivelin PC, et al. (2015) Evidence of short-term belowground transfer of nitrogen from Acacia mangium to Eucalyptus grandis trees in a tropical planted forest Soil Biol. Biochem. 91:99–108. doi:10.1016/j.soilbio.2015.08.017CrossRefGoogle Scholar
Boddey RM, Peoples MB, Palmer B, Dart PJ (2000) Use of the 15N natural abundance technique to quantify biological nitrogen fixation by woody perennials Nutr Cycl Agroecosyst 57:235–270. doi:10.1023/A:1009890514844CrossRefGoogle Scholar
Boddey RM, Polidoro JC, Resende AS, et al. (2001) Use of the 15N natural abundance technique for the quantification of the contribution of N2 fixation to sugar cane and other grasses Funct. Plant Biol. 28:889. doi:10.1071/PP01058CrossRefGoogle Scholar