Compositional Changes in Sediment Microbiota Are Associated with Seasonal Variation of the Water Column in High-Altitude Hyperarid Andean Lake Systems.

The lacustrine systems of La Brava and La Punta, located in the Tilopozo sector in the extreme south of Salar de Atacama, are pristine high-altitude Andean lakes found along the central Andes of South America. This shallow ecosystem suffers from permanent evaporation, leading to falling water levels, causing it to recede or disappear during the dry season. This dynamic causes physicochemical changes in lakes, such as low nutrient availability, pH change, and dissolved metals, which can influence the composition of the microbial community. In this study, we used a metataxonomic approach (16S rRNA hypervariable regions V3 to V4) to characterize the sedimentary microbiota of these lakes. To understand how the water column affects and is structured in the microbiota of these lakes, we combined the analysis of the persistence of the water column through satellite images and physicochemical characterization. Our results show a significant difference in abiotic factors and microbiota composition between La Punta and La Brava lakes. In addition, microbiota analysis revealed compositional changes in the ecological disaggregation (main and isolated bodies) and antagonistic changes in the abundance of certain taxa between lakes. These findings are an invaluable resource for understanding the microbiological diversity of high Andean lakes using a multidisciplinary approach that evaluates the microbiota behavior in response to abiotic factors. IMPORTANCE In this study, we analyzed the persistence of the water column through satellite images and physicochemical characterization to investigate the composition and diversity in High Andean Lake Systems in a hyperarid environment. In addition to the persistence of the water column, this approach can be used to analyze changes in the morphology of saline accumulations and persistence of snow or ice; for example, for establishing variable plant cover over time and evaluating the microbiota associated with soils with seasonal changes in plants. This makes it an ideal approach to search for novel extremophilic microorganisms with unique properties. In our case, it was used to study microorganisms capable of resisting desiccation and water restriction for a considerable period and adapting to survive in ecological niches, such as those with high UV irradiation, extreme drought, and high salt concentration.

Study of Wetland Soils of the Salar de Atacama with Different Azonal Vegetative Formations Reveals Changes in the Microbiota Associated with Hygrophile Plant Type on the Soil Surface.

Salar de Atacama is located approximately 55 km south of San Pedro de Atacama in the Antofagasta region, Chile. The high UV irradiation and salt concentration and extreme drought make Salar de Atacama an ideal site to search for novel soil microorganisms with unique properties. Here, we used a metataxonomic approach (16S rRNA V3-V4) to identify and characterize the soil microbiota associated with different surface azonal vegetation formations, including strict hygrophiles (Baccharis juncea, Juncus balticus, and Schoenoplectus americanus), transitional hygrophiles (Distichlis spicata, Lycium humile, and Tessaria absinthioides), and their various combinations. We detected compositional differences among the soil surface microbiota associated with each plant formation in the sampling area. There were changes in soil microbial phylogenetic diversity from the strict to the transitional hygrophiles. Moreover, we found alterations in the abundance of bacterial phyla and genera. Halobacteriota and Actinobacteriota might have facilitated water uptake by the transitional hygrophiles. Our findings helped to elucidate the microbiota of Salar de Atacama and associate them with the strict and transitional hygrophiles indigenous to the region. These findings could be highly relevant to future research on the symbiotic relationships between microbiota and salt-tolerant plants in the face of climate change-induced desertification. IMPORTANCE The study of the composition and diversity of the wetland soil microbiota associated with hygrophilous plants in a desert ecosystem of the high Puna in northern Chile makes it an ideal approach to search for novel extremophilic microorganisms with unique properties. These microorganisms are adapted to survive in ecological niches, such as those with high UV irradiation, extreme drought, and high salt concentration; they can be applied in various fields, such as biotechnology and astrobiology, and industries, including the pharmaceutical, food, agricultural, biofuel, cosmetic, and textile industries. These microorganisms can also be used for ecological conservation and restoration. Extreme ecosystems are a unique biological resource and biodiversity hot spots that play a crucial role in maintaining environmental sustainability. The findings could be highly relevant to future research on the symbiotic relationships between microbiota and extreme-environment-tolerant plants in the face of climate change-induced desertification.

Unraveling the Deep Genetic Architecture for Seedlessness in Grapevine and the Development and Validation of a New Set of Markers for VviAGL11-Based Gene-Assisted Selection.

Seedless inheritance has been considered a quasi-monogenic trait based on the VvAGL11 gene. An intragenic simple sequence repeat (SSR) marker, p3_VvAGL11, is currently used to opportunely discard seeded progeny, which represents up to 50% of seedlings to be established in the field. However, the rate of false positives remains significant, and this lack of accuracy might be due to a more complex genetic architecture, some intrinsic flaws of p3_VvAGL11, or potential recombination events between p3_VvAGL11 and the causal SNP located in the coding region. The purpose of this study was to update the genetic architecture of this trait in order to better understand its implications in breeding strategies. A total of 573 F1 individuals that segregate for seedlessness were genotyped with a 20K SNP chip and characterized phenotypically during four seasons for a fine QTL mapping analysis. Based on the molecular diversity of p3_VvAGL11 alleles, we redesigned this marker, and based on the causal SNP, we developed a qPCR-HRM marker for high-throughput and a Tetra-ARMS-PCR for simple predictive analyses. Up to 10 new QTLs were identified that describe the complex nature of seedlessness, corresponding to small but stable effects. The positive predictive value, based on VvAGL11 alone (0.647), was improved up to 0.814 when adding three small-effect QTLs in a multi-QTL additive model as a proof of concept. The new SSR, 5U_VviAGL11, is more informative and robust, and easier to analyze. However, we demonstrated that the association can be lost by intragenic recombination and that the e7_VviAGL11 SNP-based marker is thus more reliable and decreases the occurrence of false positives. This study highlights the bases of prediction failure based solely on a major gene and a reduced set of candidate genes, in addition to opportunities for molecular breeding following further and larger validation studies.

Interspecific reproductive barriers between sympatric populations of wild tomato species (Solanum section Lycopersicon).

PREMISE OF THE STUDY: Interspecific reproductive barriers (IRBs) often prevent hybridization between closely related species in sympatry. In the tomato clade (Solanum section Lycopersicon), interspecific interactions between natural sympatric populations have not been evaluated previously. In this study, we assessed IRBs between members of the tomato clade from nine sympatric sites in Peru. METHODS: Coflowering was assessed at sympatric sites in Peru. Using previously collected seeds from sympatric sites in Peru, we evaluated premating prezygotic (floral morphology), postmating prezygotic (pollen-tube growth), and postzygotic barriers (fruit and seed development) between sympatric species in common gardens. Pollen-tube growth and seed development were examined in reciprocal crosses between sympatric species. KEY RESULTS: We confirmed coflowering of sympatric species at five sites in Peru. We found three types of postmating prezygotic IRBs during pollen-pistil interactions: (1) unilateral pollen-tube rejection between pistils of self-incompatible species and pollen of self-compatible species; (2) potential conspecific pollen precedence in a cross between two self-incompatible species; and (3) failure of pollen tubes to target ovules. In addition, we found strong postzygotic IRBs that prevented normal seed development in 11 interspecific crosses, resulting in seed-like structures containing globular embryos and aborted endosperm and, in some cases, overgrown endothelium. Viable seed and F1 hybrid plants were recovered from three of 19 interspecific crosses. CONCLUSIONS: We have identified diverse prezygotic and postzygotic IRBs that would prevent hybridization between sympatric wild tomato species, but interspecific hybridization is possible in a few cases.

Interspecific reproductive barriers in the tomato clade: opportunities to decipher mechanisms of reproductive isolation.

The tomato clade within the genus Solanum has numerous advantages for mechanistic studies of reproductive isolation. Its thirteen closely related species, along with four closely allied Solanum species, provide a defined group with diverse mating systems that display complex interspecific reproductive barriers. Several kinds of pre- and postzygotic barriers have already been identified within this clade. Well-developed genetic maps, introgression lines, interspecific bridging lines, and the newly available draft genome sequence of the domesticated tomato (Solanum lycopersicum) are valuable tools for the genetic analysis of interspecific reproductive barriers. The excellent chromosome morphology of these diploid species allows detailed cytological analysis of interspecific hybrids. Transgenic methodologies, well developed in the Solanaceae, allow the functional testing of candidate reproductive barrier genes as well as live imaging of pollen rejection events through the use of fluorescently tagged proteins. Proteomic and transcriptomics approaches are also providing new insights into the molecular nature of interspecific barriers. Recent progress toward understanding reproductive isolation mechanisms using these molecular and genetic tools is assessed in this review.

Multiple features that distinguish unilateral incongruity and self-incompatibility in the tomato clade.

Wild tomato species in Solanum Section Lycopersicon often exhibit two types of reproductive barriers: self-incompatibility (SI) and unilateral incompatibility or incongruity (UI), wherein the success of an inter-specific cross depends on the direction of the cross. UI pollen rejection often follows the 'SI × SC' rule, i.e. pistils of SI species reject the pollen of SC (self-compatible) species but not vice versa, suggesting that the SI and UI pollen rejection mechanisms may overlap. In order to address this question, pollen tube growth was measured after inter-specific crosses using wild tomato species as the female parents and pollen from cultivated tomato (Solanum lycopersicum). Two modes of UI pollen rejection, early and late, were observed, and both differed from SI pollen rejection. The structure and expression of known stylar SI genes were evaluated. We found that S-RNase expression is not required for either the early or late mode of UI pollen rejection. However, two HT family genes, HT-A and HT-B, map to a UI QTL. Surprisingly, we found that a gene previously implicated in SI, HT-B, is mutated in both SI and SC S. habrochaites accessions, and no HT-B protein could be detected. HT-A genes were detected and expressed in all species examined, and may therefore function in both SI and UI. We conclude that there are significant differences between SI and UI in the tomato clade, in that pollen tube growth differs between these two rejection systems, and some stylar SI factors, including S-RNase and HT-B, are not required for UI.

Enfermedad de Werdnig-Hoffman: a propósito de un caso con estadía prolongada / Werdnig-Hoffman disease: a long stay in a pediatric Intensive Care Unit

El número de niños que necesita asistencia ventilatoria prolongada ha aumentado en todo el mundo en los últimos años. Se reporta una paciente con atrofia muscular espinal tipo 1 (Enfermedad de Werdnig-Hoffman) con una permanencia en la Unidad de Cuidados Intensivos Pediátricos de casi 5 años por necesidad de soporte ventilatorio crónico. Se realiza una breve revisión de la enfermedad y se analizan las características de su atención integral que han permitido una sobrevida inusualmente prolongada con excelentes condiciones físicas y mentales(AU)

The number of children that need long term mechanical ventilation is increasing worldwide. A female patient was reported with spinal muscular atrophy type 1 (Werdnig-Hoffman disease) and a stay at the Intensive Care Unit nearly to five years because she required chronic ventilatory support. A review of the illness was performed and the management strategies were analysed that have permitted an unusually prolonged survival with excellent physical and mental conditions(AU)

Enfermedad de wrrdnig-hoffman: a proposito de un caso con estadia prolongada / Werdnig-Hoffman disease. a long stay in a pediatric Intensive Care Unit

El número de niños que necesita asistencia ventilatoria prolongada ha aumentado en todo el mundo en los últimos años. Se reporta una paciente con atrofia muscular espinal tipo 1 (Enfermedad de Werdnig-Hoffman) con una permanencia en la Unidad de Cuidados Intensivos Pediátricos de casi 5 años por necesidad de soporte ventilatorio crónico. Se realiza una breve revisión de la enfermedad y se analizan las características de su atención integral que han permitido una sobrevida inusualmente prolongada con excelentes condiciones físicas y mentales.

The number of children that need long term mechanical ventilation is increasing worldwide. A female patient was reported with spinal muscular atrophy type 1 (Werdnig-Hoffman disease) and a stay at the Intensive Care Unit nearly to five years because she required chronic ventilatory support. A review of the illness was performed and the management strategies were analysed that have permitted an unusually prolonged survival with excellent physical and mental conditions.