Mycorrhizas in South American Ericaceae.

Mycorrhizal symbioses (mycorrhizas) of Ericaceae, including ericoid mycorrhiza (ErM), have been mainly studied in the Northern Hemisphere, although the highest diversity of ericaceous plants is located in the Southern Hemisphere, where several regions remain largely unexplored. One of them is South America, which harbors a remarkably high diversity of Ericaceae (691 species and 33 genera) in a wide range of environmental conditions, and a specific mycorrhizal type called cavendishioid. In this review, we compile all available information on mycorrhizas of Ericaceae in South America. We report data on the mycorrhizal type and fungal diversity in 17 and 11 ericaceous genera, respectively. We show that South American Ericaceae exhibit a high diversity of habitats and life forms and that some species from typical ErM subfamilies may also host arbuscular mycorrhiza. Also, a possible geographical pattern in South American ErM fungal communities is suggested, with Sebacinales being the dominant mycorrhizal partners of the Andean clade species from tropical mountains, while archetypal ErM fungi are common partners in southern South America species. The gathered information challenges some common assumptions about ErM and suggests that focusing on understudied regions would improve our understanding of the evolution of mycorrhizal associations in this intriguing family.

Dormancy of Floral Buds of Rabbiteye Blueberry in a Mild Winter Climate

Abstract Blueberry is an important fruit crop, with many health benefits. Despite its importance, much remains to be studied concerning the dormancy dynamics in rabbiteye cultivars growing in a mild winter climate. In this research, the dormancy in blueberry, rabbiteye cultivars 'Bluegem', 'Climax', 'Delite', and 'Powderblue', was studied in a mild winter region. The single-node cuttings biological test and the evaluation of the hydric status were performed in dormant winter reproductive buds. These experiments were performed during fall and winter in one year (2016). Moreover, chilling hours under or equal to 7.2 ºC were measured, and chill units were calculated according to Utah Model [1], Modified Utah Model [2], and Blueberry Model [3]. In conclusion, the four cultivars showed a similar pattern, revealing a dormant state in the initial sampling dates and a released dormancy in the final treatments, showing the decrease of dormancy in June and July. However, Delite was earlier than the other cultivars. Bluegem and Delite required 134.0 chilling hours, 127.0 chill units (Utah Model), 198.5 chill units (Modified Utah Model), and 971.5 chill units (Blueberry Model) for 50% of their green tip buds reach the opened bud stage. Climax required 44.0, -11.0, 56.5, and 440.5, respectively. And Powderblue required 44.0, 5.5, 77.0, and 725.0 respectively. This study can bring some insights into crop management and production of this important fruit crop, especially in a global climate-changing scenario, related to flowering and dormancy control, as well as helping to select suitable cultivars to a region, concerning chilling requirements.

Morphological and anatomical insights into de novo shoot organogenesis of in vitro 'Delite' rabbiteye blueberries.

Blueberries are valued for their taste and their high nutritional benefits, including their antioxidant and anti-inflammatory properties. In vitro culturing is an alternative method for clonal propagation, and has been used in many biotechnological studies. Most blueberry research is concentrated on highbush and lowbush taxa (Vaccinium corymbosum and Vaccinium angustifolium respectively), with only limited investigations of rabbiteye cultivars (Vaccinium virgatum) that are more suitable for subtropical climates and regions with warmer winters as a result of climate change. There is therefore a need to determine in vitro protocols for that species and group of cultivars. We examined here adventitious shoot regeneration in the 'Delite' rabbiteye blueberry cultivar. Leaf explants were cultured in vitro in Woody Plant Medium (WPM), and the effects of different thidiazuron (TDZ) concentrations, the orientation of the leaf (adaxial or abaxial surface in contact with the medium), and two portions of the leaf segment (basal or apical) were examined. De novo shoot development was studied using light and scanning electron microscopy. All concentrations of TDZ used showed similar survival and regeneration rates; 0.5 µM TDZ showed high efficiency in regenerating adventitious shoots (100%, with 57 adventitious shoots/explant), as did the adaxial surface in contact with the medium using either the apical or the basal portion of the leaf (97% shoot regeneration, 47.5 adventitious shoots/explant). Anatomical analyses showed direct and indirect organogenesis. The shoots developed leaf primordia with stomata, trichomes, and well-developed vascular tissues, with further elongation and rooting of the plants. We therefore describe here a high-efficiency regeneration method through de novo shoot organogenesis using TDZ in foliar explants of rabbiteye blueberry, with direct and indirect organogenesis.

Estudio fitoquímico de hojas de Cavendishia compacta (Ericaceae) y evaluación de su actividad antiinflamatoria / Phytochemical study of leaves of Cavendishia compacta (Ericaceae) and evaluation of its anti-inflammatory activity

RESUMEN Se realizó el estudio fitoquímico de hojas de Cavendishia compacta. La separación de extractos y fracciones por cromatografías en columna, capa delgada y capa delgada preparativa, permitieron obtener una mezcla de diterpenos conformada por kaurano, rimuneno y biformeno; una mezcla de compuestos aromáticos constituida por acetofenona y benzaldehído; una mezcla de triterpenos constituida por α-amirina y β-amirina y el aislamiento de morina y miricetina. La actividad antiinflamatoria se evaluó al extracto etanólico y las fracciones de hexano, dicolorometano y acetato de etilo, utilizando el modelo de edema auricular inducido por TPA, siendo el extracto etanólico y la fracción de dicolorometano los que presentaron un efecto antiinflamatorio moderado de 49,3% y 39,8% respectivamente.

Summary The phytochemical study of leaves of Cavendishia compacta was carried out. The separation of extracts and fractions by column chromatography, thin layer and preparative thin layer allowed to obtain a mixture of diterpenes consisting of kaurane, rimunene and biformene; a mixture of aromatic compounds constituted by acetophenone and benzaldehyde; a mixture of triterpenes constituted by α -amirine and β-amirin and the isolation of morine and myricetin. The anti-inflammatory activity was evaluated to the ethanolic extract and fractions of hexane, dichloromethane and ethyl acetate using the model of atrial edema induced by TPA, being the etha-nolic extract and the fraction of dicholoromethane those that presented a moderate anti-inflammatory effect of 49.3 % and 39.8% respectivel.

First record of Rhizoscyphus ericae in Southern Hemisphere's Ericaceae.

Ericoid mycorrhiza is arguably the least investigated mycorrhizal type, particularly when related to the number of potential hosts and the ecosystems they inhabit. Little is known about the global distribution of ericoid mycorrhizal (ErM) fungi, and this holds true even for the prominent ErM mycobiont Rhizoscyphus ericae. Earlier studies suggested R. ericae might be low in abundance or absent in the roots of Southern Hemisphere's Ericaceae, and our previous investigations in two Argentine Patagonian forests supported this view. Here, we revisited the formerly investigated area, albeit at a higher altitude, and screened fungi inhabiting hair roots of Gaultheria caespitosa and Gaultheria pumila at a treeless alpine site using the same methods as previously. We obtained 234 isolates, most of them belonging to Ascomycota. In contrast to previous findings, however, among 37 detected operational taxonomic units (OTUs), OTU 1 (=R. ericae s. str.) comprised the highest number of isolates (87, ∼37 %). Most of the OTUs and isolates belonged to the Helotiales, and 82.5 % of isolates belonged to OTUs shared between both Gaultheria species. At the alpine site, ericoid mycorrhizal fungi dominated, followed by dark septate endophytes and aquatic hyphomycetes probably acting as root endophytes. Our results suggest that the distribution of R. ericae is influenced, among others, by factors related to altitude such as soil type and presence/absence and type of the neighboring vegetation. Our study is the first report on R. ericae colonizing Ericaceae roots in the Southern Hemisphere and extends the known range of this prominent ErM species to NW Patagonia.

Preliminary phylogenetic analysis of the Andean clade and the placement of new Colombian blueberries (Ericaceae, Vaccinieae).

The blueberry tribe Vaccinieae (Ericaceae) is particularly diverse in South America and underwent extensive radiation in Colombia where many endemics occur. Recent fieldwork in Colombia has resulted in valuable additions to the phylogeny and as well in the discovery of morphologically noteworthy new species that need to be phylogenetically placed before being named. This is particularly important, as the monophyly of many of the studied genera have not been confirmed. In order to advance our understanding of the relationships within neotropical Vaccinieae and advice the taxonomy of the new blueberry relatives, here we present the most comprehensive phylogenetic analysis for the Andean clade. Anthopterus, Demosthenesia, and Pellegrinia are among the putative Andean genera recovered as monophyletic, while other eight Andean genera were not. The analyses also showed that genera that have been traditionally widely defined are non-monophyletic and could be further split into more discrete groups. Four newly discovered Colombian Vaccinieae are placed in the monophyletic Satyria s.s. and the Psammisia I clade. Although these new species are endemic to the Colombian Western Cordillera and Chocó biogeographic region and three are not known outside of Las Orquídeas National Park, they do not form sister pairs.

Estudio químico preliminar y evaluación de la actividad antioxidante, antialimentaria y tóxica, de la especie Pernettya prostrata (Ericaceae) / Preliminary chemical study and evaluation of antioxidant, antifeedant and toxic activity of the species Pernettya prostrata (Ericaceae)

Introducción: los estudios fitoquímicos y propiedades biológicas de la especie Pernettya prostrata (Cav.) DC. (Ericaceae) han sido preliminares, y muchos de los resultados publicados no son muy confiables. Por lo anterior, la planta se convierte en objeto de estudio promisorio e interesante. Objetivo: realizar el análisis fitoquímico preliminar y la evaluación de algunas propiedades biológicas de extractos y fracciones de la especie P. prostrata. Métodos: a los extractos etanólicos de parte aérea y frutos se les determinaron los posibles constituyentes mediante un análisis fitoquímico preliminar, y se evaluó la actividad antioxidante mediante la captación del radical libre DPPH, la actividad tóxica frente a Artemia salina y antialimentaria frente a Sitophilus zeamais y Tribolium castaneum. Resultados: las pruebas fitoquímicas preliminares sugieren la presencia de flavonoides, taninos triterpenos y/o esteroides en los extractos etanólicos de frutos y parte aérea, obtenidos de P. prostata. Del estudio fitoquímico realizado sobre el extracto etanólico de frutos se aisló e identificó escualeno y β-1-O-metoxiglucopiranosa. Los compuestos aislados e identificados no arrojaron resultados promisorios frente a los ensayos biológicos realizados. Los extractos etanólico de frutos (72,8 ppm) y parte aérea (60,9 ppm) presentan similar actividad antioxidante. La fracción metanólica es la de mayor actividad antioxidante con CI50 (86,2 ± 8,8 ppm) y PI (89,8 %), mayores a los del ácido ascórbico usado como patrón (CI50 = 49,3 ± 0,2 ppm). No se observó actividad tóxica y antialimentaria de los extractos y fracciones evaluados. Conclusiones: el presente trabajo realiza aportes al conocimiento químico y de las propiedades biológicas de la especie P. prostrata, mediante el aislamiento e identificación de dos sustancias nuevas y la determinación de la actividad antioxidante de algunos extractos y fracciones.

Introduction: studies about the phytochemistry and biological properties of the species Pernettya prostrata (Cav.) DC. (Ericaceae) conducted so far have been preliminary and many of the results published are not totally reliable. Therefore, the plant is an interesting and promising object of study. Objective:carry out the preliminary phytochemical analysis and evaluation of some biological properties of extracts and fractions of P. prostrata. Methods: preliminary phytochemical analysis was conducted of ethanolic extracts from the aerial parts and fruits for determination of possible constituents. Antioxidant activity was evaluated by DPPH free radical capture. Toxic activity against Artemia salina and antifeedant activity against Sitophilus zeamais and Tribolium castaneum were also determined. Results: preliminary phytochemical tests suggest the presence of flavonoids, tannins, triterpenes and/or steroids in ethanolic extracts from fruits and aerial parts of P. prostrata. Squalene and β-1-O-methoxy-glucopyranose were isolated and identified from the phytochemical study of the fruit ethanolic extract. The compounds isolated and identified did not reveal any promising results in the biological assays performed. Ethanolic extracts from fruits (72.8 ppm) and aerial parts (60.9 ppm) exhibited similar antioxidant activity. The methanolic fraction showed the highest antioxidant activity with IC 50 (86.2 ± 8.8 ppm) and IP (89.8 %), greater than those in the ascorbic acid used as a standard (IC50 = 49.3 ± 0.2 ppm). No toxic or antifeedant activity was found in the extracts and fractions evaluated. Conclusions: the present paper makes a contribution to knowledge about the chemical composition and biological properties of the species P. prostrata through isolation and identification of two new substances, and determination of the antioxidant activity of some extracts and fractions.

Micropropagação como técnica de rejuvenescimento em mirtilo (Vaccinium ashei Reade) cultivar climax / Micropropagation as a rejuvenation technique in rabbiteye blueberry (Vaccinium ashei Reade) cultivar climax

Objetivou-se com este experimento avaliar o rejuvenescimento do material vegetal através da técnica de micropropagação na produção de mudas de mirtilo, cv. Climax. Os tratamentos aplicados constituíram-se de dois tipos de citocininas (zeatina e 2iP), em quatro concentrações (0; 2,5; 5,0 e 7,5 mg.L-1) e duas fontes de explantes (plantas micropropagadas e plantas obtidas através da germinação de sementes in vitro). O delineamento experimental utilizado foi inteiramente casualizado, em esquema fatorial 2x4x2. Aos 60 dias após a instalação do experimento avaliou-se o número médio de brotos e de gemas por explante, o comprimento médio dos brotos e a taxa de multiplicação. Concluiu-se que plantas de mirtilo, micropropagadas na presença de citocinina e submetidas a sucessivas repicagens, demonstram elevada habilidade de rejuvenescimento in vitro do material adulto, podendo ser comparadas às plantas obtidas de semente, tanto na capacidade de emitir novas brotações, quanto no número de gemas e taxa de multiplicação.

This experiment was installed aiming to evaluate the plant rejuvenation capacity of rabbiteye blueberry seedlings cultivar Climax by using micropropagation technique. The treatments consisted of two cytokinin types (zeatin and 2iP), in four concentrations (0; 2.5; 5.0 and 7.5 mg.L-1) and two sources of explants (micropropagated plants and plants from in vitro seeds germination). The experiment was carried out in a 2x4x2 factorial arranged in a randomized complete design. After 60 days from experiment installation it was assessed the shoots average number and shoots average length, buds average number and the multiplication rate. In conclusion, the present results suggest that the micropropagated rabbiteye blueberry plants in the presence of cytokinin and submitted at successive cuttings showed a high in vitro rejuvenation ability of the adult material, which might be compared to the plants germinated in vitro, in the capacity of emitting new shoots as well as in the buds number and multiplication rate.