Composition and Potential Functions of Rhizobacterial Communities in a Pioneer Plant from Andean Altiplano

Plant microbiota that associate with pioneer plants are essential to their growth and adaptation to harsh conditions found in the Central Volcanic Zone of the Andes. In this sense, the rhizosphere of pioneer species represents a unique opportunity to examine how bacterial communities are recruited and support the growth of plants under abiotic stress conditions, such low nutrient availability, high solar irradiation, water scarcity, soil salinity, etc. In this study, we explored the community composition and potential functions of rhizobacteria obtained from specimens of Parastrephia quadrangularis (Meyen) Cabrera, commonly called Tola, grown on the slopes of the Guallatiri, Isluga, and Lascar volcanoes in the Atacama Desert of Chile by using 16S rRNA amplicon sequencing. Sequence analysis showed that the Actinobacteria, Proteobacteria, Acidobacteria, and Bacteroidetes were the most abundant phyla of the rhizobacterial communities examined. A similar diversity, richness, and abundance of OTUs were also observed in rhizosphere samples obtained from different plants. However, most of OTUs were not shared, suggesting that each plant recruits a specific rhizobacterial communities independently of volcanoes slope. Analyses of predicted functional activity indicated that the functions were mostly attributed to chemoheterotrophy and aerobic chemoheterotrophy, followed by nitrogen cycling (nitrate reduction and denitrification), and animal parasites or symbionts. In addition, co-occurrence analysis revealed that complex rhizobacterial interactions occur in P. quadrangularis rhizosphere and that members of the Patulibacteraceae comprise a keystone taxon. This study extends our understanding on the composition and functions of the rhizobiome, which is pivotal for the adaptability and colonization of pioneer plant to harsh conditions of the Atacama Desert, widely recognized as the driest place on planet Earth.

Variations in Flavonoid Metabolites Along Altitudinal Gradient in a Desert Medicinal Plant Agriophyllum squarrosum

Agriophyllum squarrosum (L.) Moq., a pioneer plant endemic to the temperate deserts of Asia, could be domesticated into an ideal crop with outstanding ecological and medicinal characteristics. A previous study showed differential flavonoid accumulation between two in situ altitudinal ecotypes. To verify whether this accumulation was determined by environmental or genetic factors, we conducted flavonoid-targeted metabolic profiling among 14 populations of A. squarrosum collected from regions with different altitudes based on a common garden experiment. Results showed that the most abundant flavonoid in A. squarrosum was isorhamnetin (48.40%, 557.45 μg/g), followed by quercetin (13.04%, 150.15 μg/g), tricin (11.17%, 128.70 μg/g), isoquercitrin (7.59%, 87.42 μg/g), isovitexin (7.20%, 82.94 μg/g), and rutin (7.00%, 80.62 μg/g). However, based on a common garden at middle-altitude environment, almost none of the flavonoids was enriched in the high-altitude populations, and even some flavonoids, such as quercetin, tricin, and rutin, were significantly enriched in low-altitude populations. This phenomenon indicated that the accumulation of flavonoids was not a result of local adaptation to high altitude. Furthermore, association analysis with in situ environmental variables showed that the contents of quercetin, tricin, and rutin were strongly positively correlated with latitude, longitude, and precipitation gradients and negatively correlated with temperature gradients. Thus, we could conclude that the accumulations of flavonoids in A. squarrosum were more likely as a result of local adaption to environmental heterogeneity combined with precipitation and temperature other than high altitude. This study not only provides an example to understand the molecular ecological basis of pharmacognosy, but also supplies methodologies for developing a new industrial crop with ecological and agricultural importance.

Tephrosia candida (white Tephrosia).

T. candida is a shrub 2-3 m tall, thought to be indigenous to Malaysia, and has been introduced and become naturalized in many parts of the tropics, including: Vietnam, Bhutan, Myanmar, India, Sri Lanka, Papua New Guinea, Indonesia, New Zealand, Philippines, Hawaii, and Puerto Rico. It is drought-tolerant, and commonly used in agroforestry systems. It grows well on acid and impoverished soils. Its soil improving characteristics have led to its use as a pioneer plant, in contour hedgerows to prevent soil erosion on steep slopes, as a shade tree in agroforestry systems (Nguyen and Thai, 1993), and as a nurse tree for commercial timber species (e.g. for Shorea robusta in India; Krishnaswany, 1956). It is one of the most common green manure species planted in Vietnam. Extracts from T. candida have insecticidal properties (Stoll, 1996). The flowers and fruits are susceptible to damage from Maruca vitrata (Chan Dang Dinh, 1982).

Luiz F. G. Labouriau and the dawn of seed science in Brazil

Luiz Fernando Gouvêa Labouriau (1921–1996) was a pioneer plant biologist who made significant contributions to plant physiology, mostly by bringing seed germination into a thermobiological context. His studies have set the foundations of seed science in Brazil and keep inspiring researchers until now.

Flutuação Populacional de Diclidophlebia sp. (Hemiptera: Psyllidae) em Miconia sellowiana Naudin 1851 (Melastomataceae) em Curitiba, Paraná

Imaturos e adultos de psilídeos causam diversos danos às plantas, pela sucção de seiva e injeção de toxinas o que induz, muitas das vezes, à deformação de folhas e brotações, levando a necrose, senescência de folhas e em algumas espécies, a formação de galhas. Dentre eles, o gênero Diclidophlebia Crawford, contém 25 espécies descritas sendo que sete delas atacam Melastomatacea. Miconia sellowiana é uma planta pioneira, com ampla distribuição e, no Paraná é encontrada em várias regiões fitogeográficas. Este trabalho apresenta dados relativos à flutuação populacional de uma espécie de Diclidophlebia sp. em M. sellowiana. O presente trabalho foi realizado na “Reserva Mata Viva” do Centro Politécnico da Universidade Federal do Paraná, em Curitiba, PR. Coletas quinzenais entre maio/2018 e julho/2019 foram realizadas para obtenção de ovos, imaturos e adultos do psilídeo. Os dados meteorológicos (temperatura, umidade e precipitação) foram obtidos do Sistema Meteorológico do Paraná – Simepar. Foram obtidos 1.013 ovos, 866 imaturos e 1.101 adultos. A presente pesquisa permitiu ampliar a compreender sobre a flutuação populacional de Diclidophlebia sp.. Os resultados mostraram que as baixas temperaturas são favoráveis para a produção de ovos e adultos do psilídio, mas não afeta os imaturos. Os demais fatores climáticos analisados não tiveram influência em nenhuma fase do ciclo de vida do Diclidophlebia sp., apesar de ocorrem baixas coletas no período mais chuvoso. Além disso, pelo fato de a espécie ter sido coletada em todas as fases de desenvolvimento e em todos os meses do ano fica evidenciando o seu polivoltinismo. Palavras-chave: Entomologia Florestal. Liviinae. Melastomatacea. Abstract Immatures and adults of psyllids cause several damages to the plants, by the sap suction and toxins injection which often lead to the leaves and buds deformation, necrosis, leaves senescence and in some species, the galls formation. Among them, the genus Diclidophlebia Crawford, containing 25 described species, seven of which attack Melastomatacea. Miconia sellowiana is a pioneer plant, with wide distribution and, in Paraná it is found in several phytogeographic regions. This work presents data related to the population fluctuation of a species of Diclidophlebia sp. in M. sellowiana. The present work was carried out in “Reserva Mata Viva” of Polytechnical Center of Federal University of, in Curitiba – PR. Biweekly collections between May/2018 and July/2019 were carried out to obtainimmature and adults eggs. Meteorological data (temperature, humidity and precipitation) were obtained from the Paraná Meteorological System - Simepar. During the experiment, 1,013 eggs, 866 immature and 1,101 adults were obtained. This research allowed us to broaden our understanding of the population fluctuation of Diclidophlebia sp.. The results showed that low temperatures are favorable for the eggs and adults production of the psyllid, but it does not affect the immature ones.The other climatic factors analyzed had no influence on any stage of the life cycle of Diclidophlebia sp., despite low collections in the rainiest period. In addition, due to the fact that the species was collected in all the development stages and in all months of the year, evidencing thus its polyvoltinism. Keywords: Forest Entomology. Liviinae. Melastomatacea.