Potential of Bacterial Strains Isolated from Ironstone Outcrops Bromeliads to Promote Plant Growth Under Drought Conditions.

Plant growth-promoting bacteria (PGPB) are bacteria that have mechanisms that facilitate plant growth in stress conditions such as drought. The objective of this study was to characterize bacterial strains isolated from bromeliads roots in ironstone outcrops (Urucum Residual Plateau, Mato Grosso do Sul, Brazil) for plant growth-promoting under drought conditions. Firstly, we screened isolates with the presence of 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity. Then, all isolates were tested for tolerance to drought, exopolysaccharides (EPS) production, indole-3-acetic acid (IAA)-producing abilities, phosphate and zinc solubilization, production of catalase and hydrolytic enzymes (amylase, cellulase, and protease). Germination assay and a pot experiment with maize plants submitted to well-watered and drought conditions were performed with the strains most promising (VBN11 and VBE23). Briefly, Bacillus cereus VBE23 showed in vitro higher ACC deaminase activity (3.83 and 2.52 µmol α-KB mg-1 h-1 in non-drought and drought conditions, respectively), tolerance to drought, EPS production and other mechanisms of plant growth promotion: solubilization of phosphate and zinc, ammonia production, catalase activity and production of hydrolytic enzymes (amylase, cellulase, and protease). Inoculation of strain VBE23 in maize seeds submitted to drought conditions showed higher germination concerning uninoculated seeds and inoculated with VBN11. Also, the results indicated that the isolate VBE23 provided higher values of fresh and dry biomass compared to the control of uninoculated treatment and inoculated with VBN11 under drought conditions. This is the first report on the PGPB from ironstone outcrops of Urucum Residual Plateau, Mato Grosso do Sul, Brazil. Thus, this bacterial isolate could be used as a strategy for the facilitation of plant growth in drought environments.

Cross-amplification of microsatellite loci in the cacti species from Brazilian Chaco.

Cactaceae species are an important component of the Brazilian Chaco landscape. Sixteen species are reported to this region, including 13 genera representing three Cactaceae subfamilies. All these species are native and have been locally threatened by the advance of the deforestation, which can negatively impact their genetic diversity. In order to test genetic markers that can potentially be used to screen the population diversity of these species, we checked the cross-amplification performance of 27 nuclear and 23 plastid microsatellite loci in all 16 cacti species from Brazilian Chaco. We tested the cross-amplification of the 50 microsatellite (SSR) loci in one specimen of each cacti species and considered it successful when at least one band of the expected size was generated. Thirteen species (81%) had at least 18 nuclear microsatellite loci amplified, while seven species (43%) had at least 11 chloroplast microsatellite loci amplified. We also reviewed current knowledge of SSR studies with Cactaceae in 50 studies available in the Web of Science®, and found that only five cacti species that occur in the Brazilian Chaco have representatives of the same genus with described SSR loci. The high cross-amplification rates indicated that these microsatellites markers can be helpful for future population genetic studies with cacti species from the Brazilian Chaco. Since their diversity levels and gene flow patterns are still poorly known, analyses with universal and transferable markers provide important tools to guide conservation efforts on this highly neglected region.

Azospirillum spp. from native forage grasses in Brazilian Pantanal floodplain: biodiversity and plant growth promotion potential.

A sustainable alternative to improve yield and the nutritive value of forage is the use of plant growth-promoting bacteria (PGPB) that release nutrients, synthesize plant hormones and protect against phytopathogens (among other mechanisms). Azospirillum genus is considered an important PGPB, due to the beneficial effects observed when inoculated in several plants. The aim of this study was to evaluate the diversity of new Azospirillum isolates and select bacteria according to the plant growth promotion ability in three forage species from the Brazilian Pantanal floodplain: Axonopus purpusii, Hymenachne amplexicaulis and Mesosetum chaseae. The identification of bacterial isolates was performed using specific primers for Azospirillum in PCR reactions and partial sequencing of the 16S rRNA and nifH genes. The isolates were evaluated in vitro considering biological nitrogen fixation (BNF) and indole-3-acetic acid (IAA) production. Based on the results of BNF and IAA, selected isolates and two reference strains were tested by inoculation. At 31 days after planting the plant height, shoot dry matter, shoot protein content and root volume were evaluated. All isolates were able to fix nitrogen and produce IAA, with values ranging from 25.86 to 51.26 mg N mL-1 and 107-1038 µmol L-1, respectively. The inoculation of H. amplexicaulis and A. purpusii increased root volume and shoot dry matter. There were positive effects of Azospirillum inoculation on Mesosetum chaseae regarding plant height, shoot dry matter and root volume. Isolates MAY1, MAY3 and MAY12 were considered promising for subsequent inoculation studies in field conditions.

Mating system variation and assortative mating of sympatric bromeliads (Pitcairnia spp.) endemic to neotropical inselbergs.

PREMISE OF THE STUDY: The mating system is an important component of the complex set of reproductive isolation barriers causing plant speciation. However, empirical evidence showing that the mating system may promote reproductive isolation in co-occurring species is limited. The mechanisms by which the mating system can act as a reproductive isolation barrier are also largely unknown. METHODS: Here we studied progeny arrays genotyped with microsatellites and patterns of stigma-anther separation (herkogamy) to understand the role of mating system shifts in promoting reproductive isolation between two hybridizing taxa with porous genomes, Pitcairnia albiflos and P. staminea (Bromeliaceae). KEY RESULTS: In P. staminea, we detected increased selfing and reduced herkogamy in one sympatric relative to two allopatric populations, consistent with mating system shifts in sympatry acting to maintain the species integrity of P. staminea when in contact with P. albiflos. CONCLUSIONS: Mating system variation is a result of several factors acting simultaneously in these populations. We report mating system shifts as one possible reproductive barrier between these species, acting in addition to numerous other prezygotic (i.e., flower phenology and pollination syndromes) and postzygotic barriers (Bateson-Dobzhansky-Muller genetic incompatibilities).

Metabolomic Strategies to Improve Chemical Information from OSMAC Studies of Endophytic Fungi.

Metabolomics strategies are important tools to get holistic chemical information from a system, but they are scarcely applied to endophytic fungi to understand their chemical profiles of biosynthesized metabolites. Here Penicillium sp. was cultured using One Strain Many Compounds (OSMAC) conditions as a model system to demonstrate how this strategy can help in understanding metabolic profiles and determining bioactive metabolites with the application of metabolomics and statistical analyses, as well as molecular networking. Penicillium sp. was fermented in different culture media and the crude extracts from mycelial biomass (CEm) and broth (CEb) were obtained, evaluated against bacterial strains (Staphylococcus aureus and Pseudomonas aeruginosa), and the metabolomic profiles by LC-DAD-MS were obtained and chemometrics statistical analyses were applied. The CEm and CEb extracts presented different chemical profiles and antibacterial activities; the highest activities observed were against S. aureus from CEm (MIC = 16, 64, and 128 µg/mL). The antibacterial properties from the extracts were impacted for culture media from which the strain was fermented. From the Volcano plot analysis, it was possible to determine statistically the most relevant features for the antibacterial activity, which were also confirmed from biplots of PCA as strong features for the bioactive extracts. These compounds included 75 (13-oxoverruculogen isomer), 78 (austalide P acid), 87 (austalide L or W), 88 (helvamide), 92 (viridicatumtoxin A), 96 (austalide P), 101 (dihydroaustalide K), 106 (austalide k), 110 (spirohexaline), and 112 (pre-viridicatumtoxin). Thus, these features included diketopiperazines, meroterpenoids, and polyketides, such as indole alkaloids, austalides, and viridicatumtoxin A, a rare tetracycline.

Genetic structure and phenotypic variation in wild populations of the medicinal tetraploid species Bromelia antiacantha (Bromeliaceae).

PREMISE OF THE STUDY: The patterns of genetic structure in plant populations are mainly related to the species life history and breeding system, and knowledge of these patterns is necessary for the management, use, and conservation of biological diversity. Polyploidy is considered an important mode of evolution in plants, but few studies have evaluated genetic structure of polyploid populations. We studied the patterns of genetic structure and morphological variation of Bromelia antiacantha (Bromeliaceae) populations, a polyploid terrestrial species. • METHODS: Microsatellite markers and morphological analyses were used to explore patterns of genetic and morphological diversity in wild populations of B. antiacantha. • KEY RESULTS: The results of our simple-sequence repeat analyses supported that B. antiacantha is a polyploid species. The inbreeding coefficients were high and significant in all populations (F(IS) = 0.431), indicating homozygote excess. Bromelia antiacantha showed high levels of genetic differentiation among populations (F(ST) = 0.224) and therefore was highly structured. High morphological variation was observed in fruit phenotypic traits in the populations studied. • CONCLUSIONS: The levels of genetic diversity and the pattern of the population's structure may be related to the low recruitment of seeds, clonal reproduction, and the population's colonization history. The genetic and morphological variability displayed in this study are important issues in planning the conservation and exploitation of this resource in a sustainable way.

Development of 15 nuclear microsatellite markers in Deuterocohnia (Pitcairnioideae; Bromeliaceae) using 454 pyrosequencing.

PREMISE OF THE STUDY: Microsatellite markers were developed in Deuterocohnia longipetala (Bromeliaceae) to investigate species and subspecies boundaries within the genus and the genetic diversity of natural populations. METHODS AND RESULTS: We used 454 pyrosequencing to isolate 835 microsatellite loci in D. longipetala. Of 64 loci selected for primer design, 15 were polymorphic among 23 individuals of D. longipetala and 76 individuals of the heterologous subspecies D. meziana subsp. meziana and D. meziana subsp. carmineo-viridiflora. Twelve and 13 of these loci were also polymorphic in one population each of D. brevispicata and D. seramisiana, respectively. Numbers of alleles per locus varied from two to 14 in D. longipetala, two to 12 in D. meziana, one to nine in D. brevispicata, and one to 10 in D. seramisiana. STRUCTURE analyses clearly separated the taxa from each other. CONCLUSIONS: The 15 new microsatellite markers are promising tools for studying population genetics in Deuterocohnia species.

Predicting potential distribution and evaluating biotic interactions of threatened species: a case study of Discocactus ferricola (Cactaceae) / Prevendo a distribuição potencial e avaliando interações bióticas de espécies ameaçadas: um estudo de caso de Discocactus ferricola (Cactaceae)

Abstract: Information on distribution, number of populations, and biotic interactions are essential for assessing the threat status of species and to establish more effective conservation initiatives. Ecological niche modeling have been successfully applied to identify the potential distribution, even for rare species that have few recorded occurrence points. In this study, we evaluated the potential distribution and additionally generated the first data on the reproductive biology of Discocactus ferricola, due to its degree of threat and the absence of ecological data for that species. The potential distribution map highlighted areas with higher probability of occurrence of D. ferricola on the Residual Plateau of Maciço do Urucum located in Mato Grosso do Sul, Brazil. The occurrence of D. ferricola populations was limited to outcrops of flat ironstone (cangas) distributed in patches across the landscape, increasing the chances of serious threats, such as habitat loss due to mining and species extraction. We also found that D. ferricola is xenogamous. Therefore, in situ conservation actions must prioritize the maintenance of interactions with pollinators by preserving the flora and fauna of rocky outcrops and adjacent forests in areas of greater environmental suitability for D. ferricola. Our study highlights the use of ecological niche modeling and data on biotic interactions to evaluate species potential distribution, to guide new sampling efforts, and to assist conservation and management initiatives.

Resumo: Informações sobre distribuição, número de populações e interações bióticas são essenciais para avaliar o status de ameaça das espécies e estabelecer iniciativas de conservação mais eficazes. A modelagem de nicho ecológico tem sido aplicada com sucesso para identificar a distribuição potencial, mesmo para espécies raras que possuem poucos pontos de ocorrência registrados. Neste estudo, avaliamos a distribuição potencial e adicionalmente geramos os primeiros dados sobre a biologia reprodutiva de Discocactus ferricola, devido ao seu grau de ameaça e à ausência de dados ecológicos para essa espécie. O mapa de distribuição potencial destacou áreas com maior probabilidade de ocorrência de D. ferricola no Planalto Residual do Maciço do Urucum localizado em Mato Grosso do Sul, Brasil. A ocorrência de populações de D. ferricola foi limitada aos afloramentos ferruginosos planos (cangas) que são distribuídos em manchas pela paisagem, aumentando as chances de ameaças graves, como perda de habitat devido à mineração e extração da espécie. Também descobrimos que D. ferricola é xenogâmica. Portanto, ações de conservação in situ devem priorizar a manutenção das interações com os polinizadores através da preservação da flora e da fauna nos afloramentos rochosos e florestas adjacentes nas áreas de maior adequabilidade ambiental para D. ferricola. Nesse estudo, nós destacamos o uso da modelagem de nicho ecológico e de dados sobre interações bióticas para avaliar a distribuição potencial de espécies, orientar novos esforços de amostragem e auxiliar iniciativas de conservação e manejo.