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Advisor(s)
Abstract(s)
Aromatic plants such as lavender are stirring the attention of many researchers due to their content in
bioactive secondary metabolites that can be used in traditional medicine. However, information regarding
naturally occurring lavender associated bacterial endophytes (BE) is limited. To the best of our knowledge,
this is the first study which aims to assess the phylogenetic diversity of the culturable endophytic bacteria
of Lavandula dentata cultivated under organic management and to evaluate their potential as plant growth
promoting (PGP) agents. BE were grouped by random amplified polymorphic DNA and identified by 16S
ribosomal RNA gene sequencing. Endophytes were further characterized for the ability to produce several
PGP substances, like ammonia, siderophores, indol-3-acetic acid, and hydrogen cyanide and for the ability
to solubilize phosphate. Plant cell-wall degrading enzymes were also determined. Densities of BE were
higher in roots (log 6.39 CFU g−1 fresh weight) than in shoots (log 5.56 CFU g−1 fresh weight). Phylogenetic
analysis showed that BE were affiliated to two major groups: -Proteobacteria (50%) and Firmicutes (31.6%)
and a small part belonged to - (7.9%) and -Proteobacteria (10.5%), being Pseudomonas and Bacillus
the most highly represented genera. Higher bacterial diversity was found in the lavender roots, with
endophytes belonging to 6 different genera (Pseudomonas, Variovorax, Rhizobium, Caulobacter, Bacillus
and Paenibacillus), than in shoots where only 3 genera (Bacillus, Pseudomonas and Xanthomonas) were
found. Overall, BE showed ability to produce extracellular enzymes and multiple PGP traits, suggesting
their potential use as efficient bioinoculants in sustainable cultivation of medicinal and aromatic plants.
Description
Keywords
Endophytic bacteria Diversity Indol-3-acetic acid Lavender Plant growth promotion
Citation
PEREIRA, S.I.A.; MONTEIRO, Cristina M.; VEGA, A.L.; CASTRO, Paula M. L. - Endophytic culturable bacteria colonizing Lavandula dentata L. plants: Isolation, characterization and evaluation of their plant growth-promoting activities. Ecological Engineering. ISSN 0925-8574. Vol. 87 (2016), p. 91-97 http://dx.doi.org/10.1016/j.ecoleng.2015.11.033 [short communication]