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Frost tolerance has evolved many times independently across flowering plants. However, conservation of several frost tolerance mechanisms among distant relatives suggests that apparently independent entries into freezing climates may have been facilitated by repeated modification of existing traits ('precursor traits'). One possible precursor trait for freezing tolerance is drought tolerance, because palaeoclimatic data suggest plants were exposed to drought before frost and several studies have demonstrated shared physiological and genetic responses to drought and frost stress. Here, we combine ecophysiological experiments and comparative analyses to test the hypothesis that drought tolerance acted as a precursor to frost tolerance in cool-season grasses (Pooideae). Contrary to our predictions, we measured the highest levels of frost tolerance in species with the lowest ancestral drought tolerance, indicating that the two stress responses evolved independently in different lineages. We further show that drought tolerance is more evolutionarily labile than frost tolerance. This could limit our ability to reconstruct the order in which drought and frost responses evolved relative to each other. Further research is needed to determine whether our results are unique to Pooideae or general for flowering plants. [ABSTRACT FROM AUTHOR]

Poaceae (the grass family) originated in the Cretaceous, but first dominate the palynological records of the Amazon drainage basin (ADB) in the Neogene (23 to 2.5 million years ago (Ma)). However, the ecological role of grasses in the landscape during this time remains to be resolved. In this paper, we summarise the global significance of grasses and the relevance of the fossil record, and evaluate the history of the grasses in the ADB. We present a 3-stage model of the changing role of grasses, which we based on a revision of Neogene depositional environments, the palynological record, and modern grass distribution in the Neotropics. Our model comprises the following hypotheses: (H1) assumes that from c. 23 to 9 Ma western Amazonia was dominated by a megawetland (the ‘Pebas system’) that harboured large amounts of (aquatic?) grasses. In (H2) we propose that from c. 9 Ma Andean uplift prompted megafans (extremely large alluvial fans) that extended from the Andes into the lowlands. Meanwhile, the ‘Pebas’ megawetland gradually transformed into a fluvial system. In this scenario, grasses would have had a competitive advantage and were able to colonise the newly formed megafan and fluvial landscapes. Finally, in (H3) we suggest that landscape dynamics and climatic change intensified from c. 3.5 Ma, allowing for a renewed expansion of the grasses. In addition, both the fossil and molecular records suggest that from c. 5 Ma grasses were firmly established in the tropical alpine vegetation (páramo), the tropical lowland floodplains (várzeas), and savannas (cerrado). Although further study will have to confirm the precise nature of the ADB grass history, we anticipate that abiotic processes during the Neogene and Quaternary left a strong imprint in the grass phytogeography of northern South America.

В статье рассматривается проблема номенклатуры и классификации фитолитов. На примере злаков подсемейства Pooideae юга Западной Сибири обосновано разделение морфотипа «crenate» (ICPN 2.0) на две формы: полилопастную и волнистую. Анализ литературных данных подтверждает неоднородность этого морфотипа и различные трактовки его вариаций. К первой форме были отнесены высокие в боковой проекции фитолиты с отчетливыми лопастями, ко второй группе – уплощенные формы с волнистым краем. В статье рассмотрено формирование этих двух морфотипов у 52 видов злаков, относящихся к 25 родам. Основное содержание исследования составляет анализ встречаемости форм в различных трибах и подтрибах Pooideae согласно современным сведениям о филогении злаков. На примере трех родов рассмотрены различия в формировании этих морфотипов на секционном и подродовом уровнях. В ходе детального анализа выявлено, что волнистые пластинки наиболее характерны для подтрибы Aveninae(Poeae), полилопастные частицы – для подтрибы Agrostidinae (Poeae) и трибы Meliceae. По некоторым таксонам, например, трибе Stipeae, получены неоднозначные данные, не согласующиеся с информацией по другим территориям, что указывает на необходимость дальнейших исследований обозначенной проблемы. При анализе встречаемости форм на внутриродовом уровне установлено, что в родах Poa и Festucaпрослеживаются различия между отдельными подродами и секциями, а для рода Calamagrostis такие отличия отсутствуют. Полученные результаты указывают на перспективность привлечения к классификации фитолитов филогенетической информации и необходимость более полного изучения крупных родов злаков на предмет фитолитного состава (Festuca, Calamagrostis, Poa, Stipa и др.).

One of the main intoxications to livestock in the Patagonia region of Argentina is the tremorgenic disease "Mal de Huecú", attributed to the consumption of the native grasses Poa huecu and/or Festuca argentina. In this report, five outbreaks of spontaneous intoxications were investigated. Several indole-diterpene alkaloids were identified in Poa huecu and Festuca argentina including the known tremorgen terpendole C and are likely the cause of "Mal de Huecú" disease. [Display omitted] • Poa huecu and Festuca argentina cause the tremorgenic syndrome known as Mal de Huecú. • An Epichloë -like fungal endophyte was detected in both plants. • Tremorgenic indole-diterpene alkaloids were detected in Poa huecu and Festuca argentina. [ABSTRACT FROM AUTHOR]

Poa pindariensis, a newly discovered species of Poa (family Poaceae) from Pindari Valley, Western Himalaya, is described and illustrated. Within the genus Poa, the new species belongs to P. subg. Stenopoa sect. Pandemos, and morphologically similar to P. trivialis by the sickle shape of lower glume but differs from the latter in characteristic features of habit, leaf sheath, ligules, panicle and spikelet. Additionally, data on its distribution, habitat, flowering and fruiting are given along with photo plates and distribution maps. [ABSTRACT FROM AUTHOR]

PhasiRNAs (phased, small interfering RNAs) play a crucial role in supporting male fertility in grasses. Earlier work in maize (Zea mays) and rice (Oryza sativa) - and subsequently many other plant species - identified premeiotic 21-nt and meiotic 24-nt phasiRNAs. More recently, a group of premeiotic 24-nt phasiRNAs was discovered in the anthers of two Pooideae species, barley (Hordeum vulgare) and bread wheat (Triticum aestivum). Whether premeiotic 24-nt phasiRNAs and other classes of reproductive phasiRNAs are conserved across Pooideae species remains unclear. We conducted comparative RNA profiling of three anther stages in six Pooideae species and one Bambusoideae species. We observed complex temporal accumulation patterns of 21-nt and 24-nt phasiRNAs in Pooideae and Bambusoideae grasses. In Bambusoideae, 21-nt phasiRNAs accumulated during meiosis, whereas 24-nt phasiRNAs were present in both premeiotic and postmeiotic stages. We identified premeiotic 24-nt phasiRNAs in all seven species examined. These phasiRNAs exhibit distinct biogenesis mechanisms and potential Argonaute effectors compared to meiotic 24-nt phasiRNAs. We show that specific Argonaute genes co-expressed with stage-specific phasiRNAs are conserved across Bambusoideae and Pooideae species. Our degradome analysis identified a set of conserved miRNA target genes across species, while 21-nt phasiRNA targets were species-specific. Cleavage of few targets was observed for 24-nt phasiRNAs. In summary, this study demonstrates that premeiotic 24-nt phasiRNAs are present across Bambusoideae and Pooideae families, and the temporal accumulation of other classes of 21-nt and 24-nt phasiRNA differs between bamboo and Pooideae species. Furthermore, targets of the three classes of phasiRNAs may be rapidly evolving or undetectable., (© The Author(s) 2024. Published by Oxford University Press on behalf of American Society of Plant Biologists. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Members of the grass family Poaceae have adapted to a wide range of habitats and disturbance regimes globally. The cellular structure and arrangements of leaves can help explain how plants survive in different climates, but these traits are rarely measured in grasses. Most studies are focussed on individual species or distantly related species within Poaceae. While this focus can reveal broad adaptations, it is also likely to overlook subtle adaptations within more closely related groups (subfamilies, tribes). This study, therefore, investigated the scaling relationships between leaf size, vein length area (VLA) and vessel size in five genera within the subfamily Pooideae. The scaling exponent of the relationship between leaf area and VLA was -0.46 (±0.21), which is consistent with previous studies. In Poa and Elymus , however, minor vein number and leaf length were uncorrelated, whereas in Festuca these traits were positively correlated (slope = 0.82 ± 0.8). These findings suggest there are broad-scale and fine-scale variations in leaf hydraulic traits among grasses. Future studies should consider both narrow and broad phylogenetic gradients., Competing Interests: None declared., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Annals of Botany Company.)

Poaceae is the most prominent monocot family that contains the primary cereal crops wheat, rice, and maize. These cereal species exhibit physiological diversity, such as different photosynthetic systems and environmental stress tolerance. Phosphoenolpyruvate carboxylase (PEPC) in Poaceae is encoded by a small multigene family and plays a central role in C4-photosynthesis and dicarboxylic acid metabolism. Here, to better understand the molecular basis of the cereal species diversity, we analyzed the PEPC gene family in wheat together with other grass species. We could designate seven plant-type and one bacterial-type grass PEPC groups, ppc1a, ppc1b, ppc2a, ppc2b, ppc3, ppc4, ppcC4, and ppc-b, respectively, among which ppc1b is an uncharacterized type of PEPC. Evolutionary inference revealed that these PEPCs were derived from five types of ancient PEPCs (ppc1, ppc2, ppc3, ppc4, and ppc-b) in three chromosomal blocks of the ancestral Poaceae genome. C4-photosynthetic PEPC (ppcC4) had evolved from ppc1b, which seemed to be arisen by a chromosomal duplication event. We observed that ppc1b was lost in many Oryza species but preserved in Pooideae after natural selection. In silico analysis of cereal RNA-Seq data highlighted the preferential expression of ppc1b in upper ground organs, selective up-regulation of ppc1b under osmotic stress conditions, and nitrogen response of ppc1b. Characterization of wheat ppc1b showed high levels of gene expression in young leaves, transcriptional responses under nitrogen and abiotic stress, and the presence of a Dof1 binding site, similar to ppcC4 in maize. Our results indicate the evolving status of Poaceae PEPCs and suggest the functional association of ppc1- derivatives with adaptation to environmental changes. [ABSTRACT FROM AUTHOR]

The external cues that trigger timely flowering vary greatly across tropical and temperate plant taxa, the latter relying on predictable seasonal fluctuations in temperature and photoperiod. In the grass family (Poaceae) for example, species of the subfamily Pooideae have become specialists of the northern temperate hemisphere, generating the hypothesis that their progenitor evolved a flowering response to long days from a short-day or day-neutral ancestor. Sampling across the Pooideae, we found support for this hypothesis, and identified several secondary shifts to day-neutral flowering and one to short-day flowering in a tropical highland clade. To explain the proximate mechanisms for the secondary transition back to short-day-regulated flowering, we investigated the expression of CCT domain genes, some of which are known to repress flowering in cereal grasses under specific photoperiods. We found a shift in CONSTANS 1 and CONSTANS 9 expression that coincides with the derived short-day photoperiodism of our exemplar species Nassella pubiflora. This sets up the testable hypothesis that trans - or cis -regulatory elements of these CCT domain genes were the targets of selection for major niche shifts in Pooideae grasses. [ABSTRACT FROM AUTHOR]

Trisetopsis himalayensis, a new species from the valley of the Maitoli Glacier, Western Himalaya (India), is described and illustrated. The new species is morphologically most similar to T. virescens, but differs from it in ligule, leaf blade, panicle and spikelet characters. Data on its geographical distribution, habitat and associated plant species are presented. An identification key to the species of Trisetopsis in India is also provided. [ABSTRACT FROM AUTHOR]

Background and Aims Grass silica short cell (GSSC) phytoliths appear to be the most reliable source of fossil evidence for tracking the evolutionary history and paleoecology of grasses. In recent years, modern techniques that quantitatively assess phytolith shape variation have widened opportunities for the classification of grass fossil phytoliths. However, phylogenetic, ecological and intraindividual variability patterns in phytolith shape remain largely unexplored. Methods The full range of intraindividual phytolith shape variation [3650 two-dimensional (2-D) outlines] from 73 extant grass species, 48 genera, 18 tribes and eight subfamilies (particularly Pooideae) was analysed using geometric morphometric analysis based on semi-landmarks spanning phytolith outlines. Key Results The 2-D phytolith shape is mainly driven by deep-time diversification of grass subfamilies. There is distinct phytolith shape variation in early-diverging lineages of Pooideae (Meliceae, Stipeae). The amount of intraindividual variation in phytolith shape varies among species, resulting in a remarkable pattern across grass phylogeny. Conclusions The phylogenetic pattern in phytolith shape was successfully revealed by applying geometric morphometrics to 2-D phytolith shape outlines, strengthening the potential of phytoliths to track the evolutionary history and paleoecology of grasses. Geometric morphometrics of 2-D phytolith shape is an excellent tool for analysis requiring large numbers of phytolith outlines, making it useful for quantitative palaeoecological reconstruction. [ABSTRACT FROM AUTHOR]

Adaptation to cool climates has occurred several times in different angiosperm groups. Among them, Pooideae, the largest grass subfamily with ∼3,900 species including wheat and barley, have successfully occupied many temperate regions and play a prominent role in temperate ecosystems. To investigate possible factors contributing to Pooideae adaptive evolution to cooling climates, we performed phylogenetic reconstruction using five gene sets (with 1,234 nuclear genes and their subsets) from 157 transcriptomes/genomes representing all 15 tribes and 24 of 26 subtribes. Our phylogeny supports the monophyly of all tribes (except Diarrheneae) and all subtribes with at least two species, with strongly supported resolution of their relationships. Molecular dating suggests that Pooideae originated in the late Cretaceous, with subsequent divergences under cooling conditions first among many tribes from the early middle to late Eocene and again among genera in the middle Miocene and later periods. We identified a cluster of gene duplications (CGD5) shared by the core Pooideae (with 80% Pooideae species) near the Eocene–Oligocene transition, coinciding with the transition from closed to open habitat and an upshift of diversification rate. Molecular evolutionary analyses homologs of CBF for cold resistance uncovered tandem duplications during the core Pooideae history, dramatically increasing their copy number and possibly promoting adaptation to cold habitats. Moreover, duplication of AP1 / FUL -like genes before the Pooideae origin might have facilitated the regulation of the vernalization pathway under cold environments. These and other results provide new insights into factors that likely have contributed to the successful adaptation of Pooideae members to temperate regions. [ABSTRACT FROM AUTHOR]

The proper timing of flowering, which is key to maximize reproductive success and yield, relies in many plant species on the coordination between environmental cues and endogenous developmental programs. The perception of changes in day length is one of the most reliable cues of seasonal change, and this involves the interplay between the sensing of light signals and the circadian clock. Here, we describe a Brachypodium distachyon mutant allele of the evening complex protein EARLY FLOWERING 3 (ELF3). We show that the elf3 mutant flowers more rapidly than wild type plants in short days as well as under longer photoperiods but, in very long (20 h) days, flowering is equally rapid in elf3 and wild type. Furthermore, flowering in the elf3 mutant is still sensitive to vernalization, but not to ambient temperature changes. Molecular analyses revealed that the expression of a short-day marker gene is suppressed in elf3 grown in short days, and the expression patterns of clock genes and flowering time regulators are altered. We also explored the mechanisms of photoperiodic perception in temperate grasses by exposing B. distachyon plants grown under a 12 h photoperiod to a daily night break consisting of a mixture of red and far-red light. We showed that 2 h breaks are sufficient to accelerate flowering in B. distachyon under non-inductive photoperiods and that this acceleration of flowering is mediated by red light. Finally, we discuss advances and perspectives for research on the perception of photoperiod in temperate grasses. [ABSTRACT FROM AUTHOR]

The proper timing of flowering, which is key to maximize reproductive success and yield, relies in many plant species on the coordination between environmental cues and endogenous developmental programs. The perception of changes in day length is one of the most reliable cues of seasonal change, and this involves the interplay between the sensing of light signals and the circadian clock. Here, we describe a Brachypodium distachyon mutant allele of the evening complex protein EARLY FLOWERING 3 (ELF3). We show that the elf3 mutant flowers more rapidly than wild type plants in short days as well as under longer photoperiods but, in very long (20 h) days, flowering is equally rapid in elf3 and wild type. Furthermore, flowering in the elf3 mutant is still sensitive to vernalization, but not to ambient temperature changes. Molecular analyses revealed that the expression of a short-day marker gene is suppressed in elf3 grown in short days, and the expression patterns of clock genes and flowering time regulators are altered. We also explored the mechanisms of photoperiodic perception in temperate grasses by exposing B. distachyon plants grown under a 12 h photoperiod to a daily night break consisting of a mixture of red and far-red light. We showed that 2 h breaks are sufficient to accelerate flowering in B. distachyon under non-inductive photoperiods and that this acceleration of flowering is mediated by red light. Finally, we discuss advances and perspectives for research on the perception of photoperiod in temperate grasses.

Species delimitation in the Poa taxa of the ' Cucullata complex' from the páramos of north-west South America, morphologically defined by open panicles and webbed calluses, among other characters, has been complicated by their large morphological variability coupled with a lack of available taxonomic treatments. Using multivariate morphometric and phylogenetic analyses, distinct groupings of taxa were identified including the new páramo taxa, P. bricenoi sp. nov. from Venezuela and P. cucullata subsp. cucullatella subsp. nov. from Ecuador, which are described and illustrated. Poa scabrivaginata is also presented as a new record for Ecuador and páramo vegetation in general. Based on the results from this study, updated descriptions and images are also presented for P. chirripoensis , P. cucullata s.s. , P. petrosa and P. scabrivaginata , and an identification key is provided for the species of the Cucullata complex and other open-panicled Poa spp. from Ecuador, Colombia and Venezuela. [ABSTRACT FROM AUTHOR]

Background and Aims Grasses in subfamily Pooideae live in some of the world's harshest terrestrial environments, from frigid boreal zones to the arid windswept steppe. It is hypothesized that the climate distribution of species within this group is driven by differences in climatic tolerance, and that tolerance can be partially explained by variation in stomatal traits. Methods We determined the aridity index (AI) and minimum temperature of the coldest month (MTCM) for 22 diverse Pooideae accessions and one outgroup, and used comparative methods to assess predicted relationships for climate traits versus fitness traits, stomatal diffusive conductance to water (g w) and speed of stomatal closure following drought and/or cold. Key Results Results demonstrate that AI and MTCM predict variation in survival/regreening following drought/cold, and g w under drought/cold is positively correlated with δ 13C-measured water use efficiency (WUE). However, the relationship between climate traits and fitness under drought/cold was not explained by g w or speed of stomatal closure. Conclusions These findings suggest that Pooideae distributions are at least partly determined by tolerance to aridity and above-freezing cold, but that variation in tolerance is not uniformly explained by variation in stomatal traits. [ABSTRACT FROM AUTHOR]

Two new species, Poa liuliangii and P. kengii, from the Hengduan Mountains (Sichuan province of southwest China) are described and illustrated. Detailed description and comparison tables are also provided. Poa liuliangii is similar to P. incerta and P. orinosa of the Poa versicolor aggregate (in accordance with a monotypic species concept), but differs from them in its more mesomorphic appearance (broader panicles, broader leaf blades, flag leaf blades longer than sheathes or equal) and pubescent rachillas. Poa kengii is similar to P. sphondylodes and P. faberi, but differs from them in its shorter ligules and glabrous lemma calluses. [ABSTRACT FROM AUTHOR]

Background Microsatellite loci, or single sequence repeats (SSR), are widely used as powerful markers in population genetics. They represent an attractive tool for studying plants such as grasses, whose evolution is driven by hybridisation and polyploidization. However, the development of microsatellite markers has been challenging and time-consuming, especially for non-model organisms lacking available genome-wide sequence data. One straightforward and low-cost approach is to transfer the SSR loci developed for one species, or complex, to another closely-related one. This work evaluates the transferability of microsatellite loci from homoploid to allopolyploid complexes of fine-leaved Festuca species and to assess their use in two new species. The studied complex (F. amethystina—F. tatrae) is a useful model for research on the local adaptability of grasses with different ploidy levels. Since both species can be considered as rare or threatened (F. tatrae—as a mountain and narrow endemic species and F. amethystina—a mountain species with relict lowland populations), any tool enabling studies on genetic diversity and population genetics, such as SSR markers, could also be very useful in a conservation context. Methods The ploidy level within populations was estimated using flow cytometry. One diploid and one tetraploid population of F. amethystina and a diploid population of F. tatrae were chosen to test the transferability of SSR loci. Because our work describes the transfer of SSR nuclear markers designed originally for F. gautieri, a phylogenetic tree was prepared based on the ITS marker to assess the genetic distance between the studied complexes. The PCR products were separated on a high-resolution agarose gel, intended for SSR marker analysis. Appropriate solutions for the allotetraploid population and whole mixed-ploidy complex were implemented. Results Flow cytometry confirmed earlier data regarding DNA content in the investigated species and cytotypes. The phylogenetic ITS tree indicated a small genetic distance between F. gautieri complexes and the studied species. Ten microsatellite markers were successfully transferred. All markers were polymorphic. In total, 163 different alleles were scored from the 10 SSR loci. PCoA of accessions revealed well-separated groups corresponding to studied populations. Over 60% of the total variance is explained by differentiation within populations and one third among them. Conclusions The transferred markers are valid tools for the study of population genetics and inheritance relationships within cytotypes and species and between them. The presented markers can be used to study inbreeding depression in the Festuca species, and variations in the degrees of genetic diversity between different cytotypes in mountain and lowland areas. Our findings can also be applied to study conservation strategies for ensuring biodiversity at the genetic level in polyploid complexes.

The successful introduction of the C4 pathway into C3 crops would increase photosynthetic rates and crop productivity. However, our poor understanding of how Kranz leaf anatomy develops poses a great obstacle. In particular, the origin, development, and genetics of bundle sheath (BS) cells in C4 plants are key points to elucidate. Here we report that Elymus tsukushiensis, a common C3 grass of the subfamily Pooideae, contains chloroplasts in the mestome sheath (MS) cells of the leaf, unlike most MS cells of C3 grasses. The chloroplasts are smaller than those of mesophyll cells. Immunogold localization showed that the chloroplasts and mitochondria of MS cells, respectively, accumulate ribulose 1,5-bisphosphate carboxylase/oxygenase and a photorespiratory enzyme, glycine decarboxylase, as in mesophyll cells. Thus, we suggest that the MS cells have weak photosynthetic and photorespiratory functions. This finding provides an insight into the development and evolution of C4-type BS cells in leaves of C3 grasses.

Known as a high quality forage grass, Achnatherum splendens distributes in the northwest of China, northeast, Inner Mongolia, shanxi and hebei provinces. In this study, we assembled the complete chloroplast (cp) genome of A. splendens using data from high-throughput Illumina sequencing. The A. splendens cp genome is 136,876 bp in size and includes two inverted repeat regions of 21,639 bp each, which is separated by a large single copy region of 80,958 bp and a small single copy region of 12,640 bp. A total of 130 genes were predicted, including 38 tRNA, 8 rRNA, and 84 protein-coding genes. In addition, 8 PCG genes possess a single intron, 74 PCG genes no intron, 2 other genes harbor two introns. 6 tRNA genes harbor a single intron. Phylogenetic analysis placed A. splendens within the Stipeae.

Summary: Semelparous annual plants flower a single time during their 1‐yr life cycle, investing much of their energy into rapid reproduction. By contrast, iteroparous perennial plants flower multiple times over several years, and partition their resources between reproduction and persistence. To which extent evolutionary transitions between life‐cycle strategies are internally constrained at the developmental, genetic and phylogenetic level is unknown. Here we study the evolution of life‐cycle strategies in the grass subfamily Pooideae and test if transitions between them are facilitated by evolutionary precursors.We integrate ecological, life‐cycle strategy and growth data in a phylogenetic framework. We investigate if growth traits are candidates for a precursor.Species in certain Pooideae clades are predisposed to evolve annuality from perenniality, potentially due to the shared inheritance of specific evolutionary precursors. Seasonal dry climates, which have been linked to annuality, were only able to select for transitions to annuality when the precursor was present. Allocation of more resources to above‐ground rather than below‐ground growth is a candidate for the precursor.Our findings support the hypothesis that only certain lineages can respond quickly to changing external conditions by switching their life‐cycle strategy, likely due to the presence of evolutionary precursors. [ABSTRACT FROM AUTHOR]

Epichloë fungal endophytes that systemically colonise cool-season grasses have become an internationally well-researched symbiosis. While sexual species of Epichloë can cause choke disease of grass seed heads, asexual forms are symptomless endophytes that colonise embryos to become seed transmitted. In mutualistic associations, the grass benefits through greater tolerance of abiotic and biotic stresses. In New Zealand, at least 12 species of naturalised and native grasses have been documented as infected with a range of asexual or sexual Epichloë. The impact of endophyte-infected ryegrass and tall fescue has been significant for pastoral farmers, with Epichloë enhancing pasture performance. Production of bioactive secondary metabolites reduces herbivory by invertebrate pests but some are also toxic to grazing animals. Selected strains of Epichloë have been utilised to reduce livestock problems while retaining improved pasture performance. Documented Epichloë-infected native grasses are rare, justifying greater efforts of discovery, description and conservation as taonga (a treasure) for Māori and all New Zealanders. Given their ecological success in New Zealand ecosystems, along with economic and environmental benefits, there are good prospects to further develop both endemic and naturalised Epichloë-grass associations that may benefit other cool-season grasses and potentially deliver new beneficial properties. [ABSTRACT FROM AUTHOR]

Background. Microsatellite loci, or single sequence repeats (SSR), are widely used as powerful markers in population genetics. They represent an attractive tool for studying plants such as grasses, whose evolution is driven by hybridisation and polyploidization. However, the development of microsatellite markers has been challenging and time-consuming, especially for non-model organisms lacking available genome-wide sequence data. One straightforward and low-cost approach is to transfer the SSR loci developed for one species, or complex, to another closely-related one. This work evaluates the transferability of microsatellite loci from homoploid to allopolyploid complexes of fine-leaved Festuca species and to assess their use in two new species. The studied complex (F. amethystina-F. tatrae) is a useful model for research on the local adaptability of grasses with different ploidy levels. Since both species can be considered as rare or threatened (F. tatrae-as a mountain and narrow endemic species and F. amethystina-a mountain species with relict lowland populations), any tool enabling studies on genetic diversity and population genetics, such as SSR markers, could also be very useful in a conservation context. Methods. The ploidy level within populations was estimated using flow cytometry. One diploid and one tetraploid population of F. amethystina and a diploid population of F. tatrae were chosen to test the transferability of SSR loci. Because our work describes the transfer of SSR nuclear markers designed originally for F. gautieri, a phylogenetic tree was prepared based on the ITS marker to assess the genetic distance between the studied complexes. The PCR products were separated on a high-resolution agarose gel, intended for SSR marker analysis. Appropriate solutions for the allotetraploid population and whole mixed-ploidy complex were implemented. Results. Flow cytometry confirmed earlier data regarding DNA content in the investigated species and cytotypes. The phylogenetic ITS tree indicated a small genetic distance between F. gautieri complexes and the studied species. Ten microsatellite markers were successfully transferred. All markers were polymorphic. In total, 163 different alleles were scored from the 10 SSR loci. PCoA of accessions revealed well-separated groups corresponding to studied populations. Over 60% of the total variance is explained by differentiation within populations and one third among them. Conclusions. The transferred markers are valid tools for the study of population genetics and inheritance relationships within cytotypes and species and between them. The presented markers can be used to study inbreeding depression in the Festuca species, and variations in the degrees of genetic diversity between different cytotypes in mountain and lowland areas. Our findings can also be applied to study conservation strategies for ensuring biodiversity at the genetic level in polyploid complexes. [ABSTRACT FROM AUTHOR]

Three subfamilies of grasses, the Erhardtoideae (rice), the Panicoideae (maize, sorghum, sugar cane and millet), and the Pooideae (wheat, barley and cool season forage grasses) provide the basis of human nutrition and are poised to become major sources of renewable energy. Here we describe the complete genome sequence of the wild grass Brachypodium distachyon (Brachypodium), the first member of the Pooideae subfamily to be completely sequenced. Comparison of the Brachypodium, rice and sorghum genomes reveals a precise sequence- based history of genome evolution across a broad diversity of the grass family and identifies nested insertions of whole chromosomes into centromeric regions as a predominant mechanism driving chromosome evolution in the grasses. The relatively compact genome of Brachypodium is maintained by a balance of retroelement replication and loss. The complete genome sequence of Brachypodium, coupled to its exceptional promise as a model system for grass research, will support the development of new energy and food crops

Epichloë is a genus of filamentous fungal endophytes that has co-evolved with cool-season grasses with which they form long-term, symbiotic associations. The most agriculturally important associations for pasture persistence for grazing livestock are those between asexual vertically transmitted Epichloë strains and the pasture species, perennial ryegrass, and tall fescue. The fungus confers additional traits to their host grasses including invertebrate pest deterrence and drought tolerance. Selected strains of these mutualistic endophytes have been developed into highly efficacious biocontrol products and are widely utilized within the Americas, Australia, and New Zealand for pasture persistence. Less publicized is the antagonism Epichloë endophytes display towards multiple species of saprophytic and pathogenic microbes. This opinion piece will review the current literature on antimicrobial properties exhibited by this genus of endophyte and discuss the reasons why this trait has historically remained a research curiosity rather than a trait of commercial significance.

Aim: Frost is among the most dramatic stresses a plant can experience, and complex physiological adaptations are needed to endure long periods of sub‐zero temperatures. Owing to the need to evolve these complex adaptations, transitioning from tropical to temperate climates is regarded as difficult. Here, we study the transition from tropical to temperate climates in the grass subfamily Pooideae, which dominates cool temperate, continental and Arctic regions. We produce a dated phylogeny and investigate the role of climate cooling in diversification. Location: Global, temperate regions. Time period: Cretaceous–Cenozoic. Major taxa: Pooideae. Methods: Using newly available fossils and methods, we dated a comprehensive Pooideae phylogeny and tested for the impact of palaeoclimates on diversification rates. Using ancestral state reconstruction, we investigated whether Pooideae ancestors experienced frost and winter. To locate the ancestral distribution area of Pooideae, we performed biogeographical analyses. Results: We estimated a Late Cretaceous/early Palaeocene origin of the Pooideae (61–77 Ma), with all major clades already having diversified at the Eocene–Oligocene climate cooling (34 Ma). Climate cooling was a probable driving force of Pooideae diversification. Pooideae probably evolved in a temperate niche experiencing frost, but not long winters. Main conclusion: Pooideae probably originated in a temperate niche and experienced cold temperatures and frost long before expansion of temperate biomes after the Eocene–Oligocene transition. This suggests that the Pooideae ancestor had adaptations to temperate climate and that certain responses to low‐temperature stress are shared in extant Pooideae grasses. Throughout the Cenozoic, falling temperatures and expansion of temperate biomes were associated with an increase in diversification. However, complex mechanisms for enduring strongly seasonal climate with long, cold winters most probably evolved independently in daughter lineages. Our findings provide insight into how adaptations to historical changes in chill and frost exposure influence the distribution of plant diversity today. [ABSTRACT FROM AUTHOR]

Se cita por primera vez el género Peyritschia para el Perú, representado por dos especies, P. pringlei y P. deyeuxioides. El género se describe y se diferencia en una clave de los géneros afines Trisetum y Deschampsia. P. deyeuxioides y P. pringlei se describen, incluyéndose sinónimos, distribución geográfica y hábitat. Las dos especies se ilustran sobre la base de sus caracteres vegetativos y

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The successful introduction of the C4 pathway into C3 crops would increase photosynthetic rates and crop productivity. However, our poor understanding of how Kranz leaf anatomy develops poses a great obstacle. In particular, the origin, development, and genetics of bundle sheath (BS) cells in C4 plants are key points to elucidate. Here we report that Elymus tsukushiensis, a common C3 grass of the subfamily Pooideae, contains chloroplasts in the mestome sheath (MS) cells of the leaf, unlike most MS cells of C3 grasses. The chloroplasts are smaller than those of mesophyll cells. Immunogold localization showed that the chloroplasts and mitochondria of MS cells, respectively, accumulate ribulose 1,5-bisphosphate carboxylase/oxygenase and a photorespiratory enzyme, glycine decarboxylase, as in mesophyll cells. Thus, we suggest that the MS cells have weak photosynthetic and photorespiratory functions. This finding provides an insight into the development and evolution of C4-type BS cells in leaves of C3 grasses. [ABSTRACT FROM AUTHOR]

* Angiosperm adaptations to seasonally cold climates have occurred multiple times independently. However, the observation that less than half of all angiosperm families are represented in temperate latitudes suggests internal constraints on the evolution of cold tolerance/avoidance strategies. Similar to angiosperms as a whole, grasses are primarily tropical, but one major clade, subfamily Pooideae, radiated extensively within temperate regions. It is posited that this Pooideae niche transition was facilitated by an early origin of long-term cold responsiveness around the base of the subfamily, and that a set of more ancient pathways enabled evolution of seasonal cold tolerance. * To test this, we compared transcriptome-level responses of disparate Pooideae to short-/long-term cold and with those previously known in the subtropical grass rice (Ehrhartoideae). * Analyses identified several highly conserved cold-responsive 'orthogroups' within our focal Pooideae species that originated successively during the diversification of land plants, predominantly via gene duplication. The majority of conserved Pooideae cold-responsive genes appear to have ancient roles in stress responses, with most of the orthogroups also being sensitive to cold in rice. However, a subgroup of genes was likely co-opted de novo early in the Pooideae. * These results highlight a plausible stepwise evolutionary trajectory for cold adaptations across Pooideae. [ABSTRACT FROM AUTHOR]

Pyrrolizidine alkaloids (PAs) are a class of secondary metabolites found in various unrelated angiosperm lineages including cool-season grasses (Poaceae, subfamily Pooideae). Thesinine conjugates, saturated forms of PA that are regarded as non-toxic, have been described to occur in the two grass species Lolium perenne and Festuca arundinacea (Poaceae, subfamily Pooideae). In a wider screen, we tested various species of the Pooideae lineage, grown under controlled conditions, for their ability to produce thesinine conjugates or related structures. Using an LC-MS based targeted metabolomics approach we were able to show that PA biosynthesis in grasses is limited to a group of very closely related Pooideae species that produce a limited diversity of PA structures. High variability in PA levels was observed even between individuals of the same species. These individual accumulation patterns are discussed with respect to a possible function and evolution of this type of alkaloid.

Pyrrolizidine alkaloids (PAs) are a class of secondary metabolites found in various unrelated angiosperm lineages including cool-season grasses (Poaceae, subfamily Pooideae). Thesinine conjugates, saturated forms of PA that are regarded as non-toxic, have been described to occur in the two grass species Lolium perenne and Festuca arundinacea (Poaceae, subfamily Pooideae). In a wider screen, we tested various species of the Pooideae lineage, grown under controlled conditions, for their ability to produce thesinine conjugates or related structures. Using an LC-MS based targeted metabolomics approach we were able to show that PA biosynthesis in grasses is limited to a group of very closely related Pooideae species that produce a limited diversity of PA structures. High variability in PA levels was observed even between individuals of the same species. These individual accumulation patterns are discussed with respect to a possible function and evolution of this type of alkaloid. [ABSTRACT FROM AUTHOR]

Flowering time is a carefully regulated trait controlled primarily through the action of the central genetic regulator, FLOWERING LOCUS T ( FT ). Recently it was demonstrated that a microRNA, miR5200 , targets the end of the second exon of FT under short-day photoperiods in the grass subfamily Pooideae, thus preventing FT transcripts from reaching threshold levels under non-inductive conditions. Pooideae are an interesting group in that they rapidly diversified from the tropics into the northern temperate region during a major global cooling event spanning the Eocene-Oligocene transition. We hypothesize that miR5200 photoperiod-sensitive regulation of Pooideae flowering time networks assisted their transition into northern seasonal environments. Here, we test predictions derived from this hypothesis that miR5200, originally found in bread wheat and later identified in Brachypodium distachyon , (1) was present in the genome of the Pooideae common ancestor, (2) is transcriptionally regulated by photoperiod, and (3) is negatively correlated with FT transcript abundance, indicative of miR5200 regulating FT. Our results demonstrate that miR5200 did evolve at or around the base of Pooideae, but only acquired photoperiod-regulated transcription within the Brachypodium lineage. Based on expression profiles and previous data, we posit that the progenitor of miR5200 was co-regulated with FT by an unknown mechanism. [ABSTRACT FROM AUTHOR]