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"Conselho Nacional de Desenvolvimento Científico e Tecnológico"
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Convergent losses of decay mechanisms and rapid turnover of symbiosis genes in mycorrhizal mutualists
To elucidate the genetic bases of mycorrhizal lifestyle evolution, we sequenced new fungal genomes, including 13 ectomycorrhizal (ECM), orchid (ORM) and ericoid (ERM) species, and five saprotrophs, which we analyzed along with other fungal genomes. Ectomycorrhizal fungi have a reduced complement of genes encoding plant cell wall-degrading enzymes (PCWDEs), as compared to their ancestral wood decayers. Nevertheless, they have retained a unique array of PCWDEs, thus suggesting that they possess diverse abilities to decompose lignocellulose. Similar functional categories of nonorthologous genes are induced in symbiosis. Of induced genes, 7-38% are orphan genes, including genes that encode secreted effector-like proteins. Convergent evolution of the mycorrhizal habit in fungi occurred via the repeated evolution of a 'symbiosis toolkit', with reduced numbers of PCWDEs and lineage-specific suites of mycorrhiza-induced genes.
Journal Article
Landscapes—a lens for assessing sustainability
There are urgent calls to transition society to more sustainable trajectories, at scales ranging from local to global. Landscape sustainability (LS), or the capacity for landscapes to provide equitable access to ecosystem services essential for human wellbeing for both current and future generations, provides an operational approach to monitor these transitions. However, the complexity of landscapes complicates how and what to consider when assessing LS.Objectives: To identify important features of landscapes that remain challenging to consider in LS assessments and provide guidance to strengthen future assessments.Methods: We conducted two workshops to identify the complex features of landscapes that remain under-considered in LS assessments, and developed guidelines on how to better incorporate these features.Results: We identify open and connected boundaries and diversity of values as landscape features that must be better considered in LS assessments or risk exacerbating offstage sustainability burdens and power inequalities. We provide guidelines to avoid these pitfalls which emphasize assessing ecosystem service interactions across interconnected landscapes and incorporating local actors’ diverse values.Conclusions: Our guidelines provide a stepping stone for researchers and practitioners to better incorporate landscape complexities into LS assessments to inform landscape-level decisions and actions.
Journal Article
Inoculation with Plant Growth-Promoting Bacteria Improves the Sustainability of Tropical Pastures with Megathyrsus maximus
Brazil is the second-largest producer and the first exporter of beef, with herds mainly raised in extensive pastures, where Megathyrsus maximus occupies over 30 Mha. About 70% of the pastures are under degradation, and using plant growth-promoting bacteria (PGPB) may contribute to reversing this scenario. We investigated the effects of PGPB on the growth of six cultivars of M. maximus—Tanzania-1, Massai, BRS Zuri, Mombaça, BRS Tamani, and BRS Quênia—under greenhouse conditions. Plants were inoculated, or not, with the elite strains of Azospirillum brasilense CNPSo 2083 + CNPSo 2084, Bacillus subtilis CNPSo 2657, Pseudomonas fluorescens CNPSo 2719, or Rhizobium tropici CNPSo 103. At 35 days after emergence, plants were evaluated for ten root growth traits, shoot dry weight, and the levels of macro and micronutrients accumulated in shoots. Several root traits were increased due to inoculation in all genotypes, impacting plant growth and nutrient uptake. Despite the differences in effectiveness, all genotypes benefited from PGPB to some degree, but Mombaça and BRS Zuri were more responsive. Scanning electron microscopy indicated that bacterial species differed in their capacity to colonize seeds and rootlets. The results show that inoculation with elite PGPB strains may represent an important strategy for the sustainability of M. maximus pastures.
Journal Article
Projected climate-driven shifts in coral distribution indicate tropicalisation of Southwestern Atlantic reefs
Aim: Predicting and acting on the future of ecosystems requires understanding species distribution shifts due to climate change. We investigated which corals are more likely to shift their distribution in the Southwestern Atlantic under a warming scenario. Location: Southwestern Atlantic (SWA; 1° N–28° S). Methods: We used spatial distribution models with a Bayesian approach to predict the current and future (2050 and 2100) coral occurrence probabilities of 12 zooxanthellate corals and hydrocorals under an intermediate scenario of increasing greenhouse gas emissions (RCP6.0) projected by the Intergovernmental Panel on Climate Change (IPCC). Results: We found a decline in the occurrence probabilities of all 12 taxa within the tropics (1° N–20° S) and an increase towards subtropical sites (20–28° S) as early as 2050. The most significant declines are projected to occur between 9° S and 20° S, a region that currently hosts the richest reef complex in the South Atlantic, the Abrolhos bank. The imminent loss of suitable habitat in the tropics mostly threatens the Brazilian endemics and range restricted corals Mussismilia braziliensis and Mussismilia harttii, while more widely distributed taxa such as Siderastrea spp., Millepora spp. and Porites spp. are expected to expand their ranges southwards. Main Conclusions: The projected declines in the tropical region are likely to reduce structural complexity causing biodiversity loss. The overall increase in occurrence probabilities in subtropical areas indicates tropicalisation of SWA reefs, which may benefit species already established in these areas and potentially enrich coral assemblages through the range expansion of taxa that currently do not occur in the region. These findings emphasise the need to support ecological corridors that could aid coral migration towards more suitable habitats under climate change.
Journal Article
Transcontinental Patterns in Floral Pigment Abundance Among Animal-pollinated Species
Flower color arises primarily from pigments that serve dual functions: attracting pollinators and mitigating environmental stresses. Among major pigment types, anthocyanins and UV-absorbing phenylpropanoids (UAPs) fulfill one or both roles and should be widespread. Our review of the UV-vis absorption profiles of major floral pigments demonstrates that UAPs are the primary UV protectants. Next, we analyzed the floral pigment composition of 926 animal-pollinated species from California, Southern Spain, and Southeastern Brazil. UAPs were ubiquitous (the “dark matter” of the flower). Among the remaining pigment types, ~ 56% of species had anthocyanins, ~ 37% had carotenoids, and ~ 17% had chlorophylls (some species had > 1 pigment type). Pigment abundance varied in response to abiotic and biotic factors, particularly with pollinator type in California. Despite regional differences in environmental filtering, pollination guilds, and relatedness, UAPs are omnipresent and there is a transcontinental stable distribution of flower colors and their underlying floral pigments.
Journal Article
Non-native fishes in Brazilian freshwaters: identifying biases and gaps in ecological research
Brazil is the country in the world with the highest freshwater fish diversity. Because of the high rates of species introduction, the number of publications about invasive fish has increased in the last decades in this country. We conducted a systematic review of the literature to identify knowledge patterns and gaps related to the introduction of non-native fishes in distinct Brazilian freshwater ecosystems. Compared to the last official report, we found that the number of records in the literature is three times greater, with at least 352 non-native freshwater fish species (255 translocated and 97 exotics). Studies were concentrated in developed and impacted regions of the country and were mostly conducted in reservoirs and rivers. Only 7% of the studies tested invasion hypotheses, mainly those in the so-called Darwin’s and trait concept clusters. Studies that assessed the effects of non-native species investigated a few species, such as Oreochromis niloticus, Coptodon rendalli, or Cichla kelberi. However, the impacts of most species, especially those translocated among Brazilian ecoregions, remain largely unexplored. Therefore, the fish invasion literature in Brazil still has relevant knowledge gaps, biases, and research topics needing investigation. This picture prevents a proper understanding of the ecological and socio-economic consequences of fish introductions to native ecosystems, especially in highly biodiverse regions such as the Amazon. Future research and government agendas should fill these knowledge gaps to allow the establishment of effective surveillance, control, and management programs for non-native fishes in Brazilian freshwaters.
Journal Article
Biodiversity of octopuses in the Americas
During work on this paper, RGG was supported by CONACYT (Consejo Nacional de Ciencia y Tecnología, México) PhD scholarship 464700; IABS was supported by a grant from the Universidad Autónoma Metropolitana (MX, UAM-147.09.01, 04, 07); author PB was supported by Brazilian Coordination of Superior Level Staff Improvement (CAPES)—Finance Code 001 [grant number 88881.068194/2014-01]; MDSI was supported by CONACYT within the framework of Estancias Posdoctorales en el Extranjero 2019–2021; TL and FDL were supported by CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Brazil) Project Ciencias do Mar II (CAPES-2203/2014); UM was supported by SENESCYT through the PROMETEO Program during his stay at the Instituto Nacional de Pesca of Ecuador; NO was supported by CONICET (National Council of Scientific and Technical Research, Argentina); MCPG was supported by INACH (Instituto Antártico Chileno, Chile) RG 50-18; EAGV was supported by the Brazilian National Research Council (CNPq- grants # 316391/2021-2, #426797/2018-3); and IGG was supported in part by JST (Japan Science and Technology Agency) Grant AS2715164U.
Journal Article
Knocking-down Meloidogyne incognita proteases by plant-delivered dsRNA has negative pleiotropic effect on nematode vigor
The root-knot nematode Meloidogyne incognita causes serious damage and yield losses in numerous important crops worldwide. Analysis of the M. incognita genome revealed a vast number of proteases belonging to five different catalytic classes. Several reports indicate that M. incognita proteases could play important roles in nematode parasitism, besides their function in ordinary digestion of giant cell contents for feeding. The precise roles of these proteins during parasitism however are still unknown, making them interesting targets for gene silencing to address protein function. In this study we have knocked-down an aspartic (Mi-asp-1), a serine (Mi-ser-1) and a cysteine protease (Mi-cpl-1) by RNAi interference to get an insight into the function of these enzymes during a host/nematode interaction. Tobacco lines expressing dsRNA for Mi-ser-1 (dsSER), Mi-cpl-1 (dsCPL) and for the three genes together (dsFusion) were generated. Histological analysis of galls did not show clear differences in giant cell morphology. Interestingly, nematodes that infected plants expressing dsRNA for proteases produced a reduced number of eggs. In addition, nematode progeny matured in dsSER plants had reduced success in egg hatching, while progeny resulting from dsCPL and dsFusion plants were less successful to infect wild-type host plants. Quantitative PCR analysis confirmed a reduction in transcripts for Mi-cpl-1 and Mi-ser-1 proteases. Our results indicate that these proteases are possibly involved in different processes throughout nematode development, like nutrition, reproduction and embryogenesis. A better understanding of nematode proteases and their possible role during a plant-nematode interaction might help to develop new tools for phytonematode control.
Journal Article
Evolutionary diversification of galactinol synthases in Rosaceae: adaptive roles of galactinol and raffinose during apple bud dormancy
Galactinol synthase (GolS) is a key enzyme in the biosynthetic pathway of raffinose family oligosaccharides (RFOs), which play roles in carbon storage, signal transduction, and osmoprotection. The present work assessed the evolutionary history of GolS genes across the Rosaceae using several bioinformatic tools. Apple (Malus x domestica) GolS genes were transcriptionally characterized during bud dormancy, in parallel with galactinol and raffinose measurements. Additionally, MdGolS2, a candidate to regulate seasonal galactinol and RFO content during apple bud dormancy, was functionally characterized in Arabidopsis. Evolutionary analyses revealed that whole genome duplications have driven GolS gene evolution and diversification in Rosaceae speciation. The strong purifying selection identified in duplicated GolS genes suggests that differential gene expression might define gene function better than protein structure. Interestingly, MdGolS2 was differentially expressed during bud dormancy, concomitantly with the highest galactinol and raffinose levels. One of the intrinsic adaptive features of bud dormancy is limited availability of free water; therefore, we generated transgenic Arabidopsis plants expressing MdGolS2. They showed higher galactinol and raffinose contents and increased tolerance to water deficit. Our results suggest that MdGolS2 is the major GolS responsible for RFO accumulation during apple dormancy, and these carbohydrates help to protect dormant buds against limited water supply.
Journal Article