Characterization of plant growth-promoting bacteria inhabiting Vriesea gigantea Gaud. and Tillandsia aeranthos (Loiseleur) L.B. Smith (Bromeliaceae)

Abstract

Abstract:Microorganisms that live inside and around a plant can supply it with essential substances, such as phytohormones and essential nutrients. The present investigation aimed to isolate and characterize the phyllosphere, the endophytic, and the water tank bacteria associated with Vriesea gigantea and Tillandsia aeranthos . The bacteria were tested for siderophore and indole-3-acetic acid (IAA) production, phosphate solubilization, and presence of the nif H gene. Genetic diversity of the bacterial isolates was evaluated by rep-PCR. Sixty-eight bacterial strains were isolated from 3 different microhabitats of V. gigantea and from 2 microhabitats of T. aeranthos bromeliad plants. Gram-positive, spore-forming bacilli comprised most bacterial isolates. All isolates produced IAA in vitro in presence of very low amounts of tryptophan. More than 70% of the evaluated bacteria presented the ability of siderophore production and phosphate solubilization, and possessed the nif H gene. It was not possible to distinguish well-defined groups of isolates based on the bromeliad species and microhabitat they inhabit using genetic characterization by rep-PCR. Water tanks presented the most abundant diversity compared with phyllosphere and endophytes, probably due to the high nutrient concentration, which promotes an ideal environment for complex microbial communities. Keywords: bromeliads, PGPB, diazotrophic bacteria, water tank, siderophore, IAA. Neotrop., vol. 13, no. 3 our knowledge, none study has described or selected PGPB or other bacteria associated to these two species of bromeliads. For this reason, the aims of the present investigation were to isolate and characterize the phyllosphere, endophytic, and water tank bacteria associated with individuals of V. gigantea and T. aeranthos collected in southern Brazil. Those two species were chosen due to the morphological differences in the water uptake method: a water tank in V. gigantea and trichomes in T. aeranthos.

Diversity of new root nodule bacteria from Erythrina velutina Willd., a native legume from the Caatinga dry forest (Northeastern Brazil)

“…Among the cultivated species, studies conducted in Brazil have already examined the genetic variability of rhizobia of legumes such as pigeonpea (Costa et al, 2014), peanuts (Lyra et al, 2013;TorresJúnior et al, 2014), common beans (Stocco et al, 2008), among others. This technique is also used to examine the variability of strains isolated from native plants such as bromeliad (Giongo et al, 2013), wild rice (Fernandes Júnior et al, 2013) and legumes (Granada et al, 2014). The results obtained in the present study, demonstrate its applicability and indicate that this technique can be used with rhizobia of other native tree legumes.…”

Seasonal Physiological Parameters and Phytotelmata Bacterial Diversity of Two Bromeliad Species (Aechmea gamosepala and Vriesea platynema) from the Atlantic Forest of Southern Brazil

“…There are few studies on the prokaryotic and eukaryotic communities from phytotelmata of Southern Brazilian bromeliads [18,24,82]. Our survey presents the description of bacterial communities from bromeliad phytotelmata using DNA metabarcoding, the seasonal physiological changes of the host plants and some of their possible interactions in the Atlantic Forest in southern Brazil.…”

Functional structure of the bromeliad tank microbiome is strongly shaped by local geochemical conditions

“…A great number of organisms, including bacteria, archaea, fungi, protozoans, insects, amphibians and reptiles, spend part or all of their life cycle in these tanks (Rocha et al, 2000). These organisms can engage in a plethora of interactions and ecosystem processes including active nitrogen fixation (Brighigna et al, 1992;Goffredi et al, 2011b;Giongo et al, 2013), photosynthesis (Bouard et al, 2012), chemolithotrophy (Goffredi et al, 2011a), herbivory, predation and detritivory (Ngai and Srivastava, 2006). Extensive research on protist and animal communities in bromeliad tanks reveals a food web structure that is comparable in complexity to much larger aquatic ecosystems (Richardson, 1999;Kitching, 2000;Rocha et al, 2000;Marino et al, 2013).…”