Grass survey of the Itremo Massif records endemic central highland grasses

Despite the substantial area covered by grasslands in Madagascar (65%), the taxonomy of the grasses (Poaceae), which represent the main plant component of these vegetation types, is still understudied. Inventories and detailed specimen identification work from 1 2 localities in the Itremo Massif Protected Area allowed us to compile a list of grasses present in the area. In total, members of eight subfamilies, 56 genera, and 99 species have been recorded from the Itremo Massif. Grasslands cover 75% of the Itremo Massif Protected Area and are dominated by Panicoideae (65%) and by C4 plants. The genera Eragrostis and Panicum, with nine and eight species respectively, are the best represented genera in Itremo. Eragrostis betsileensis and Tristachya betsileensis are the two species known to be local endemics. Twenty species are endemic to the central highlands, and a further 1 4 species are restricted to Madagascar. Five ecological groups of grasses were identified in the Itremo Massif: shade species in gallery forests, open wet area species, fire grasses, anthropogenic disturbance associated grasses and rock-dwelling grasses. Grasslands of the Itremo Massif are likely to be at least partly natural as shown by their richness in terms of endemic and native grass species. Conservation of such grasslands is thus an important issue, not only for grasses but for all species that inhabit these open canopy habitats

Fire and grazing determined grasslands of central Madagascar represent ancient assemblages

The ecology of Madagascar's grasslands is under-investigated and the dearth of ecological understanding of how disturbance by fire and grazing shapes these grasslands stems from a perception that disturbance shaped Malagasy grasslands only after human arrival. However, worldwide, fire and grazing shape tropical grasslands over ecological and evolutionary timescales, and it is curious Madagascar should be a global anomaly. We examined the functional and community ecology of Madagascar's grasslands across 71 communities in the Central Highlands. Combining multivariate abundance models of community composition and clustering of grass functional traits, we identified distinct grass assemblages each shaped by fire or grazing. The fire-maintained assemblage is primarily composed of tall caespitose species with narrow leaves and low bulk density. By contrast, the grazer-maintained assemblage is characterized by mat-forming, high bulk density grasses with wide leaves. Within each assemblage, levels of endemism, diversity and grass ages support these as ancient assemblages. Grazer-dependent grasses can only have co-evolved with a now-extinct megafauna. Ironically, the human introduction of cattle probably introduced a megafaunal substitute facilitating modern day persistence of a grazer-maintained grass assemblage in an otherwise defaunated landscape, where these landscapes now support the livelihoods of millions of people

Heteropogon ‐ Themeda grasses evolve to occupy either tropical grassland or wetland biomes

Species of the Heteropogon‐Themeda clade are ecologically important grasses distributed across the tropics, including widespread species, such as the pantropical Heteropogon contortus and Themeda triandra, and range‐restricted species such as Heteropogon ritchiei and Themeda anathera. Here, we examine habitat preferences of the grassland/savanna and wetland species by describing bioclimatic niche characteristics, characterizing functional traits, and investigating the evolution of functional traits of 31 species in the Heteropogon‐Themeda clade in relation to precipitation and temperature. The climatic limits of the clade are linked to mean annual precipitation and seasonality that also distinguish seven wetland species from 24 grassland/savanna species. Tests of niche equivalency highlighted the unique bioclimatic niche of the wetland species. However, climatic factors do not fully explain species geographic range, and other factors are likely to contribute to their distribution ranges. Trait analyses demonstrated that the wetland and grassland/savanna species were separated by culm height, leaf length, leaf area, awn length, and awn types. Phylogenetic analyses showed that the wetland species had tall stature with long and large leaves and lack of hygroscopic awns, which suggest selective pressures in the shift between savanna/grassland and wetland. The two most widespread species, H. contortus and T. triandra, have significantly different bioclimatic niches, but we also found that climatic niche alone does not explain the current geographic distributions of H. contortus and T. triandra. Our study provides a new understanding of the biogeography and evolutionary history of an ecologically important clade of C4 tropical grasses

The origin and morphological character evolution of the paleotropical woody bamboos

The woody bamboos (Bambusoideae) exhibit distinctive biological traits within Poaceae, such as highly lignified culms, rapid shoot growth, monocarpic mass flowering and nutlike or fleshy caryopses. Much of the remarkable morphological diversity across the subfamily exists within a single hexaploid clade, the paleotropical woody bamboos (PWB), making it ideal to investigate the factors underlying morphological evolution in woody bamboos. However, the origin and biogeographical history of PWB remain elusive, as does the effect of environmental factors on the evolution of their morphological characters. We generated a robust and time-calibrated phylogeny of PWB using single nucleotide polymorphisms retrieved from optimized double digest restriction site associated DNA sequencing, and explored the evolutionary trends of habit, inflorescence, and caryopsis type in relation to environmental factors including climate, soil, and topography. We inferred that the PWB started to diversify across the Oligocene–Miocene boundary and formed four major clades, that is, Melocanninae, Racemobambosinae s.l. (comprising Dinochloinae, Greslanlinae, Racemobambosinae s.str. and Temburongiinae), Hickeliinae and Bambusinae s.l. (comprising Bambusinae s.str. plus Holttumochloinae). The ancestor of PWB was reconstructed as having erect habit, indeterminate inflorescence and basic caryopsis. The characters including climbing/scrambling habit, determinate inflorescence, and nucoid/bacoid caryopsis have since undergone multiple changes and reversals during the diversification of PWB. The evolution of all three traits was correlated with, and hence likely influenced by, aspects of climate, topography, and soil, with climate factors most strongly correlated with morphological traits, and soil factors least so. However, topography had more influence than climate or soil on the evolution of erect habit, whereas both factors had greater effect on the evolution of bacoid caryopsis than did soil. Our results provide novel insights into morphological diversity and adaptive evolution in bamboos for future ecological and evolutionary research.</p

A 250 plastome phylogeny of the grass family (Poaceae): topological support under different data partitions

The systematics of grasses has advanced through applications of plastome phylogenomics, although studies have been largely limited to subfamilies or other subgroups of Poaceae. Here we present a plastome phylogenomic analysis of 250 complete plastomes (179 genera) sampled from 44 of the 52 tribes of Poaceae. Plastome sequences were determined from high throughput sequencing libraries and the assemblies represent over 28.7 Mbases of sequence data. Phylogenetic signal was characterized in 14 partitions, including (1) complete plastomes; (2) protein coding regions; (3) noncoding regions; and (4) three loci commonly used in single and multi-gene studies of grasses. Each of the four main partitions was further refined, alternatively including or excluding positively selected codons and also the gaps introduced by the alignment. All 76 protein coding plastome loci were found to be predominantly under purifying selection, but specific codons were found to be under positive selection in 65 loci. The loci that have been widely used in multi-gene phylogenetic studies had among the highest proportions of positively selected codons, suggesting caution in the interpretation of these earlier results. Plastome phylogenomic analyses confirmed the backbone topology for Poaceae with maximum bootstrap support (BP). Among the 14 analyses, 82 clades out of 309 resolved were maximally supported in all trees. Analyses of newly sequenced plastomes were in agreement with current classifications. Five of seven partitions in which alignment gaps were removed retrieved Panicoideae as sister to the remaining PACMAD subfamilies. Alternative topologies were recovered in trees from partitions that included alignment gaps. This suggests that ambiguities in aligning these uncertain regions might introduce a false signal. Resolution of these and other critical branch points in the phylogeny of Poaceae will help to better understand the selective forces that drove the radiation of the BOP and PACMAD clades comprising more than 99.9% of grass diversity

Contrasted histories of organelle and nuclear genomes underlying physiological diversification in a grass species: Intraspecific dispersal of C4 physiology

C 4 photosynthesis evolved multiple times independently in angiosperms, but most origins are relatively old so that the early events linked to photosynthetic diversification are blurred. The grass Alloteropsis semialata is an exception, as this species encompasses C 4 and non-C 4 populations. Using phylogenomics and population genomics, we infer the history of dispersal and secondary gene flow before, during and after photosynthetic divergence in A. semialata. We further analyse the genome composition of individuals with varied ploidy levels to establish the origins of polyploids in this species. Detailed organelle phylogenies indicate limited seed dispersal within the mountainous region of origin and the emergence of a C 4 lineage after dispersal to warmer areas of lower elevation. Nuclear genome analyses highlight repeated secondary gene flow. In particular, the nuclear genome associated with the C 4 phenotype was swept into a distantly related maternal lineage probably via unidirectional pollen flow. Multiple intraspecific allopolyploidy events mediated additional secondary genetic exchanges between photosynthetic types. Overall, our results show that limited dispersal and isolation allowed lineage divergence, with photosynthetic innovation happening after migration to new environments, and pollen-mediated gene flow led to the rapid spread of the derived C 4 physiology away from its region of origin.This study was funded by the European Research Council (grant no. ERC-2014-STG-638333), the Royal Society (grant no. RGF\EA\181050) and has benefited from ‘Investissements d'Avenir' grants managed by the Agence Nationale de la Recherche (CEBA, ref. ANR-10-LABX-25-01 and TULIP, ref. ANR-10-LABX-41). Edinburgh Genomics, which contributed to the sequencing, is partly supported through core grants from the NERC (grant no. R8/H10/ 56), MRC (grant no. MR/K001744/1) and BBSRC (grant no. BB/ J004243/1). P.A.C. is funded by a Royal Society University Research Fellowship (grant no. URF\R\180022).Abstract 1. Introduction 2. Materials and methods (a) Sampling, sequencing and data filtering (b) Genome sizing and carbon isotope analyses (c) Assembly of organelle genomes and molecular dating (d) Phylogenetic analyses of the nuclear genome (e) Genetic structure (f) Genome composition 3. Results (a) Genome sizes (b) Time-calibrated organelle phylogenies (c) Nuclear phylogeny (d) Population structure and genome composition 4. Discussion (a) Limited seed dispersal in the region of origin (b) Widespread pollen flow and sweep of the C4 nuclear genome (c) Recurrent hybridization and polyploidization 5. Concluding remarks Data accessibility Authors' contributions Competing interests Funding Acknowledgements Footnote

Botanical Monography in the Anthropocene

Unprecedented changes in the Earth's biota are prompting urgent efforts to describe and conserve plant diversity. For centuries, botanical monographs — comprehensive systematic treatments of a family or genus — have been the gold standard for disseminating scientific information to accelerate research. The lack of a monograph compounds the risk that undiscovered species become extinct before they can be studied and conserved. Progress towards estimating the Tree of Life and digital information resources now bring even the most ambitious monographs within reach. Here, we recommend best practices to complete monographs urgently, especially for tropical plant groups under imminent threat or with expected socioeconomic benefits. We also highlight the renewed relevance and potential impact of monographies for the understanding, sustainable use, and conservation of biodiversity.Fil: Grace, Olwen M.. Royal Botanic Gardens, Kew; Reino UnidoFil: Pérez-Escobar, Oscar A.. Royal Botanic Gardens, Kew; Reino UnidoFil: Lucas, Eve J.. Royal Botanic Gardens, Kew; Reino UnidoFil: Vorontsova, Maria S.. Royal Botanic Gardens, Kew; Reino UnidoFil: Lewis, Gwilym P.. Royal Botanic Gardens, Kew; Reino UnidoFil: Walker, Barnaby E.. Royal Botanic Gardens, Kew; Reino UnidoFil: Lohmann, Lúcia G.. Universidade de Sao Paulo; BrasilFil: Knapp, Sandra. Natural History Museum; Reino UnidoFil: Wilkie, Peter. Royal Botanic Gardens; Reino UnidoFil: Sarkinen, Tiina. Royal Botanic Gardens; Reino UnidoFil: Darbyshire, Iain. Royal Botanic Gardens; Reino UnidoFil: Lughadha, Eimear Nic. Royal Botanic Gardens; Reino UnidoFil: Monro, Alexandre. Royal Botanic Gardens; Reino UnidoFil: Woudstra, Yannick. Universidad de Copenhagen; Dinamarca. Royal Botanic Gardens; Reino UnidoFil: Demissew, Sebsebe. Addis Ababa University; EtiopíaFil: Muasya, A. Muthama. University Of Cape Town; SudáfricaFil: Díaz, Sandra Myrna. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Baker, William J.. Royal Botanic Gardens, Kew; Reino UnidoFil: Antonelli, Alexandre. University of Oxford; Reino Unido. University Goteborg; Sueci

Antitumor Activity of Auger Electron Emitter 111In Delivered by Modular Nanotransporter for Treatment of Bladder Cancer With EGFR Overexpression

Gamma-ray emitting 111In, which is extensively used for imaging, is also a source of short-range Auger electrons (AE). While exhibiting negligible effect outside cells, these AE become highly toxic near DNA within the cell nucleus. Therefore, these radionuclides can be used as a therapeutic anticancer agent if delivered precisely into the nuclei of tumor target cells. Modular nanotransporters (MNTs) designed to provide receptor-targeted delivery of short-range therapeutic cargoes into the nuclei of target cells are perspective candidates for specific intracellular delivery of AE emitters. The objective of this study was to evaluate the in vitro and in vivo efficacy of 111In attached MNTs to kill human bladder cancer cells overexpressing epidermal growth factor receptor (EGFR). The cytotoxicity of 111In delivered by the EGFR-targeted MNT (111In-MNT) was greatly enhanced on EJ-, HT-1376-, and 5637-expressing EGFR bladder cancer cell lines compared with 111In non-targeted control. In vivo microSPECT/CT imaging and antitumor efficacy studies revealed prolonged intratumoral retention of 111In-MNT with t½ = 4.1 ± 0.5 days as well as significant dose-dependent tumor growth delay (up to 90% growth inhibition) after local infusion of 111In-MNT in EJ xenograft-bearing mice