Cytonuclear interplay in auto- and allopolyploids: a multifaceted perspective from the Festuca-Lolium complex.

Restoring cytonuclear stoichiometry is necessary after whole-genome duplication (WGD) and interspecific/intergeneric hybridization in plants. We investigated this phenomenon in auto- and allopolyploids of the Festuca-Lolium complex providing insights into the mechanisms governing cytonuclear interactions in early polyploid and hybrid generations. Our study examined the main processes potentially involved in restoring the cytonuclear balance after WGD comparing diploids and new and well-established autopolyploids. We uncovered that both the number of chloroplasts and the number of chloroplast genome copies were significantly higher in the newly established autopolyploids and grew further in more established autopolyploids. The increase in the copy number of the chloroplast genome exceeded the rise in the number of chloroplasts and fully compensated for the doubling of the nuclear genome. In addition, changes in nuclear and organelle gene expression were insignificant. Allopolyploid Festuca × Lolium hybrids displayed potential structural conflicts in parental protein variants within the cytonuclear complexes. While biased maternal allele expression has been observed in numerous hybrids, our results suggest that its role in cytonuclear stabilization in the Festuca × Lolium hybrids is limited. This study provides insights into the restoration of the cytonuclear stoichiometry, yet it emphasizes the need for future research to explore post-transcriptional regulation and its impact on cytonuclear gene expression stoichiometry. Our findings may enhance the understanding of polyploid plant evolution, with broader implications for the study of cytonuclear interactions in diverse biological contexts.

Effects of atmospheric CO2 concentration on transpiration and leaf elongation responses to drought in Triticum aestivum, Lolium perenne and Festuca arundinacea.

BACKGROUND AND AIMS: Leaf elongation is vital for Poaceae species' productivity, influenced by atmospheric CO2 concentration ([CO2]) and climate-induced water availability changes. Although [CO2] mitigates the effects of drought on reducing transpiration per unit leaf area, it also increases total leaf area and water use. These complex interactions associated with leaf growth pose challenges in anticipating climate change effects. This study aims to assess [CO2] effects on leaf growth response to drought in perennial ryegrass (Lolium perenne), tall fescue (Festuca arundinacea) and wheat (Triticum aestivum). METHODS: Plants were cultivated in growth chambers with [CO2] at 200 or 800 ppm. At leaf six to seven unfolding, half of the plants were subjected to severe drought treatment. Leaf elongation rate (LER) was measured daily, whereas plant transpiration was continuously recorded gravimetrically. Additionally, water-soluble carbohydrate (WSC) content along with water and osmotic potentials in the leaf growing zone were measured at drought onset, mid-drought and leaf growth cessation. KEY RESULTS: Elevated [CO2] mitigated drought impacts on LER and delayed growth cessation across species. A positive correlation between LER and soil relative water content (SRWC) was observed. At the same SRWC, perennial grasses exhibited a higher LER with elevated [CO2], likely due to enhanced stomatal regulation. Despite stomatal closure and WSC accumulation, CO2 did not influence nighttime water potential or osmotic potential. The marked increase in leaf area across species resulted in similar (wheat and tall fescue) or higher (ryegrass) total water use by the experiment's end, under both watered and unwatered conditions. CONCLUSIONS: In conclusion, elevated [CO2] mitigates the adverse effects of drought on leaf elongation in three Poaceae species, due to its impact on plant transpiration. Overall, these findings provide valuable insights into CO2 and drought interactions that may help anticipate plant responses to climate change.

Effect of magnetized water irrigation on Cd subcellular allocation and chemical forms in leaves of Festuca arundinacea during phytoremediation.

The application of an external magnetic field has been shown to improve the Cd phytoremediation efficiency of F. arundinacea by leaf harvesting. However, the influencing mechanisms of the promoting effect have not yet been revealed. This study evaluated variations in the Cd subcellular allocation and fractions in various F. arundinacea leaves, with or without magnetized water irrigation. Over 50 % of the metal were sequestered within the cell wall in all tissues under all treatments, indicating that cell wall binding was a critical detoxification pathway for Cd. After magnetized water treatment, the metal stored in the cytoplasm of roots raised from 33.1 % to 45.3 %, and the quantity of soluble Cd in plant roots enhanced from 53.4 % to 59.0 %. The findings suggested that magnetized water mobilized Cd in the roots, and thus drove it into the leaves. In addition, the proportion of Cd in the organelles, and the concentration of ethanol-extracted Cd in emerging leaves, decreased by 13.0 % and 47.1 %, respectively, after magnetized water treatment. These results explained why an external field improved the phytoextraction effect of the plant through leaf harvesting.

Dig up tall fescue plastid genomes for the identification of morphotype-specific DNA variants.

BACKGROUND: Tall fescue (Festuca arundinacea Schreb.) is an important cool-season perennial grass species. Hexaploid tall fescue has three distinct morphotypes used either as forage or turf purposes. Its chloroplast genome is conserved due to it being maternally inherited to the next generation progenies. To identify morphotype-specific DNA markers and the genetic variations, plastid genomes of all three tall fescue morphotypes, i.e., Continental cv. Texoma MaxQ II, Rhizomatous cv. Torpedo, and Mediterranean cv. Resolute, have been sequenced using Illumina MiSeq sequencing platform. RESULTS: The plastid genomes of Continental-, Rhizomatous-, and Mediterranean tall fescue were assembled into circular master molecules of 135,283 bp, 135,336 bp, and 135,324 bp, respectively. The tall fescue plastid genome of all morphotypes contained 77 protein-coding, 20 tRNAs, four rRNAs, two pseudo protein-coding, and three hypothetical protein-coding genes. We identified 630 SNPs and 124 InDels between Continental and Mediterranean, 62 SNPs and 20 InDels between Continental and Rhizomatous, and 635 SNPs and 123 InDels between Rhizomatous and Mediterranean tall fescue. Only four InDels in four genes (ccsA, rps18, accD, and ndhH-p) were identified, which discriminated Continental and Rhizomatous plastid genomes from the Mediterranean plastid genome. Here, we identified and reported eight InDel markers (NRITCHL18, NRITCHL35, NRITCHL43, NRITCHL65, NRITCHL72, NRITCHL101, NRITCHL104, and NRITCHL110) from the intergenic regions that can successfully discriminate tall fescue morphotypes. Divergence time estimation revealed that Mediterranean tall fescue evolved approximately 7.09 Mya, whereas the divergence between Continental- and Rhizomatous tall fescue occurred about 0.6 Mya. CONCLUSIONS: To our knowledge, this is the first report of the assembled plastid genomes of Rhizomatous and Mediterranean tall fescue. Our results will help to identify tall fescue morphotypes at the time of pre-breeding and will contribute to the development of lawn and forage types of commercial varieties.

Drought survival and recovery in grasses: Stress intensity and plant-plant interactions impact plant dehydration tolerance.

Plant dehydration tolerance confers drought survival in grasses, but the mortality thresholds according to soil water content (SWC), vapour pressure deficit (VPD) and plant-plant interactions are little explored. We compared the dehydration dynamics of leaf meristems, which are the key surviving organs, plant mortality, and recovery of Mediterranean and temperate populations of two perennial grass species, Dactylis glomerata and Festuca arundinacea, grown in monocultures and mixtures under a low-VPD (1.5 kPa) versus a high-VPD drought (2.2 kPa). The lethal drought index (LD50 ), that is, SWC associated with 50% plant mortality, ranged from 2.87% (ψs = -1.68 MPa) to 2.19% (ψs = -4.47 MPa) and reached the lowest values under the low-VPD drought. Populations of D. glomerata were more dehydration-tolerant (lower LD50 ), survived and recovered better than F. arundinacea populations. Plant-plant interactions modified dehydration tolerance and improved post-drought recovery in mixtures compared with monocultures. Water content as low as 20.7%-36.1% in leaf meristems allowed 50% of plants to survive. We conclude that meristem dehydration causes plant mortality and that drought acclimation can increase dehydration tolerance. Genetic diversity, acclimation and plant-plant interactions are essential sources of dehydration tolerance variability to consider when predicting drought-induced mortality.

Metabolism of crown tissue is crucial for drought tolerance and recovery after stress cessation in Lolium/Festuca forage grasses.

A process of plant recovery after drought cessation is a complex trait which has not been fully recognized. The most important organ associated with this phenomenon in monocots, including forage grasses, is the crown tissue located between shoots and roots. The crown tissue is a meristematic crossroads for metabolites and other compounds between these two plant organs. Here, for the first time, we present a metabolomic and lipidomic study focused on the crown tissue under drought and recovery in forage grasses, important for agriculture in European temperate regions. The plant materials involve high (HDT) and low drought-tolerant (LDT) genotypes of Festuca arundinacea, and Lolium multiflorum/F. arundinacea introgression forms. The obtained results clearly demonstrated that remodeling patterns of the primary metabolome and lipidome in the crown under drought and recovery were different between HDT and LDT plants. Furthermore, HDT plants accumulated higher contents of primary metabolites under drought in the crown tissue, especially carbohydrates which could function as osmoprotectants and storage materials. On the other hand, LDT plants characterized by higher membranes damage under drought, simultaneously accumulated membrane phospholipids in the crown and possessed the capacity to recover their metabolic functions after stress cessation to the levels observed in HDT plants.

Intraspecific phylogeny of a Patagonian fescue: differentiation at molecular markers and morphological traits suggests hybridization at peripheral populations.

BACKGROUND AND AIMS: Grasses of the Festuca genus have complex phylogenetic relations due to morphological similarities among species and interspecific hybridization processes. Within Patagonian fescues, information concerning phylogenetic relationships is very scarce. In Festuca pallescens, a widely distributed species, the high phenotypic variability and the occurrence of interspecific hybridization preclude a clear identification of the populations. Given the relevance of natural rangelands for livestock production and their high degradation due to climate change, conservation actions are needed and knowledge about genetic variation is required. METHODS: To unravel the intraspecific phylogenetic relations and to detect genetic differences, we studied 21 populations of the species along its natural geographical distribution by coupling both molecular [internal transcribed spacer (ITS) and trnL-F markers] and morpho-anatomical analyses. Bayesian inference, maximum likelihood and maximum parsimony methods were applied to assemble a phylogenetic tree, including other native species. The morphological data set was analysed by discriminant and cluster analyses. KEY RESULTS: The combined information of the Bayesian tree (ITS marker), the geographical distribution of haplotype variants (trnL-F marker) and the morpho-anatomical traits, distinguished populations located at the margins of the distribution. Some of the variants detected were shared with other sympatric species of fescues. CONCLUSIONS: These results suggest the occurrence of hybridization processes between species of the genus at peripheral sites characterized by suboptimal conditions, which might be key to the survival of these populations.

Chromosome-scale assembly and annotation of the perennial ryegrass genome.

BACKGROUND: The availability of chromosome-scale genome assemblies is fundamentally important to advance genetics and breeding in crops, as well as for evolutionary and comparative genomics. The improvement of long-read sequencing technologies and the advent of optical mapping and chromosome conformation capture technologies in the last few years, significantly promoted the development of chromosome-scale genome assemblies of model plants and crop species. In grasses, chromosome-scale genome assemblies recently became available for cultivated and wild species of the Triticeae subfamily. Development of state-of-the-art genomic resources in species of the Poeae subfamily, which includes important crops like fescues and ryegrasses, is lagging behind the progress in the cereal species. RESULTS: Here, we report a new chromosome-scale genome sequence assembly for perennial ryegrass, obtained by combining PacBio long-read sequencing, Illumina short-read polishing, BioNano optical mapping and Hi-C scaffolding. More than 90% of the total genome size of perennial ryegrass (approximately 2.55 Gb) is covered by seven pseudo-chromosomes that show high levels of collinearity to the orthologous chromosomes of Triticeae species. The transposon fraction of perennial ryegrass was found to be relatively low, approximately 35% of the total genome content, which is less than half of the genome repeat content of cultivated cereal species. We predicted 54,629 high-confidence gene models, 10,287 long non-coding RNAs and a total of 8,393 short non-coding RNAs in the perennial ryegrass genome. CONCLUSIONS: The new reference genome sequence and annotation presented here are valuable resources for comparative genomic studies in grasses, as well as for breeding applications and will expedite the development of productive varieties in perennial ryegrass and related species.

The Role of Triacylglycerol in the Protection of Cells against Lipotoxicity under Drought in Lolium multiflorum/Festucaarundinacea Introgression Forms.

Triacylglycerol is a key lipid compound involved in maintaining homeostasis of both membrane lipids and free fatty acids (FFA) in plant cells under adverse environmental conditions. However, its role in the process of lipid remodeling has not been fully recognized, especially in monocots, including grass species. For our study, two closely related introgression forms of Lolium multiflorum (Italian ryegrass) and Festuca arundinacea (tall fescue), distinct in their level of drought tolerance, were selected as plant models to study rearrangements in plant lipidome under water deficit and further re-watering. The low drought tolerant (LDT) form revealed an elevated level of cellular membrane damage accompanied by an increased content of polyunsaturated FFA and triacylglycerol under water deficit, compared with the high drought tolerant (HDT) form. However, the LDT introgression form demonstrated also the ability to regenerate its membranes after stress cessation. The obtained results clearly indicated that accumulation of triacylglycerol under advanced drought in the LDT form could serve as a cellular protective mechanism against overaccumulation of toxic polyunsaturated FFA and other lipid intermediates. Furthermore, accumulation of triacylglycerol under drought conditions could serve also as storage of substrates required for further regeneration of membranes after stress cessation. The rearrangements in triacylglycerol metabolism were supported by the upregulation of several genes, involved in a biosynthesis of triacylglycerol. With respect to this process, diacylglycerol O-acyltransferase DGAT2 seems to play the most important role in the analyzed grasses.

Cloning and in silico characterization of cinnamyl alcohol dehydrogenase gene involved in lignification of Tall fescue (Festuca arundinacea Schreb.).

Tall fescue, a promising temperate forage grass of Himalayan region, possesses extraordinary property of rapid growth with high biomass production, but its poor digestibility due to higher lignin content limits its utilization in livestock feeding. The lignification in Tall fescue is under the control of enzymatic cascade of different regulatory enzymes. Cinnamyl alcohol dehydrogenase (CAD) is a crucial regulatory enzyme that catalyzes the last step of monolignol biosynthesis and is a potential candidate for altering the content and types of lignin, and hence increasing the digestibility of fodder crops. Hence, the present investigation was conducted on isolation, cloning and characterization of CAD gene from Tall fescue. Isolation and amplification of CAD gene resulted in an amplicon of 1521 bp. The CAD gene sequence was submitted to NCBI database with an accession number MW442831. Translation of the CAD gene sequence exhibited an ORF of 361 amino acids. The deduced CAD protein was predicted to be hydrophobic, acidic and thermally stable with molecular formula C1712H2734N460O520S23, molecular mass of 38.82 kDa, theoretical pI of 5.60 and 3 strong transmembrane helices. The CAD protein was predicted to have a dimer forming behavior with putative NAD(P) binding site between amino acids 48 and 301, putative substrate-binding site between amino acids 48 and 301, catalytic zinc-binding site between amino acids 48 and 164 and structural zinc-binding site between amino acid residue 101 and 115. A conserved 189GLGGVG194 motif is the binding site for NADP(H). The conserved motif pattern of CAD's zinc catalytic center was found to be 69GHEVVGEV(X)EVG(X)2V83. The zinc-binding site was found to be conserved between amino acid 89 and 115 and was found to be 89G(X)2VG(X)G(X)2VGXC(X)2C(X)2C(X)5QYC115. The deciphered sequence and putative protein information might be useful in subsequent research in lignin bioengineering for enhanced digestibility, biomass conversion as well as impact of lignin on cell wall mechanics.

Suitable coverage and slope guided by soil and water conservation can prevent non-point source pollution diffusion: A case study of grassland.

Non-point source pollution caused by surface runoff has been a popular hydrological and environmental safety issue and has attracted extensive attention from global scholars. To identify the optimal vegetation coverage of Festuca arundinacea grassland for controlling soil erosion and purifying surface runoff, bare land was chosen as the control in this experiment. Simulated rainfall experiments were carried out with three levels of coverage (low coverage, moderate coverage and full coverage) under four slope conditions (flat slope, gentle slope, medium slope, and steep slope) and at four rainfall intensities (moderate rainfall, heavy rainfall, rainstorm and heavy rainstorm). The comprehensive evaluation results suggested that the capacity of Festuca arundinacea grassland for reducing the surface runoff, sediment yield, suspended solids (SS), total nitrogen (TN), total phosphorus (TP) and chemical oxygen demand (COD) decreased with increasing rainfall intensity and slope but increased with increasing vegetation coverage. Structural equation model (SEM) results suggested that there were positive relationships between the vegetation coverage and purification capacity index and negative correlations between the rainfall intensity and slope and the purification capacity index. The response surface analysis results suggested that the optimal vegetation coverage should be higher than 84% and that the slope should be smaller than 10° for controlling soil erosion and avoiding pollution via diffusion with surface runoff in Festuca arundinacea grassland. This study proposes recommendations for the vegetation configuration pattern in the development and management of runoff purification systems.

Elevated atmospheric CO2 enhances the phytoremediation efficiency of tall fescue (Festuca arundinacea) in Cd-polluted soil.

With the economic development of society, concentrations of atmospheric CO2 and heavy metals in soils have been increasing. The physiological responses of plants to the interaction between soil pollution and climatic change need to be understood. Pot experiments were designed to assess variations in Festuca arundinacea dry weight, leaf type, chlorophyll content, antioxidase activities, and Cd accumulation ability, under different atmospheric CO2 treatments. The results showed that the total dry weights increased with increasing CO2, and Cd concentrations in falling leaf tissues increased with raised atmospheric CO2, before reaching a peak at 600 ppm, above which they remained constant. Compared with the control (400 ppm), 600, 650, and 700 ppm CO2 treatments increased the proportions of the falling tissues by 1.7%, 3.3%, and 4.5%, respectively. Antioxidant enzyme activities in plant leaves increased with increasing atmospheric CO2 levels. The concentration of H2O2 in leaf tissues increased with increasing CO2, reaching a peak at 600 ppm, and then decreased significantly as the CO2 content increased further, to 700 ppm. The results in this study suggest that F. arundinacea could be regarded as a potential candidate for phytoremediation of Cd-polluted soil; especially if senescent and dead leaf tissues could be harvested, and that raised atmospheric CO2 levels could improve its soil remediation efficiency.Novelty statement Extrapolation of results from experiments of environmental impacts in greenhouse to real scale field requires to be considered cautiously. External factors such as water, temperature, humidity, and pollution are variable in real field. Plants will face a lot of beneficial or detrimental conditions which will influence the magnitude of the results. However, the elevation of CO2 is an inevitable phenomenon in future. Therefore, findings from experiments under artificial conditions are sometime a good choice to obtain knowledge about elevated CO2 related impacts on phytoremediation efficiency of a specific plant. The final goal of this work is to find a suitable CO2 fumigation strategy optimized for soil remediation. We report on that elevated atmospheric CO2 can increase the phytoremediation efficiency of Festuca arundinacea for Cd. This is significant because the combined influences of elevated atmospheric CO2 and metal pollution in terms of biomass yield, pollutant uptake, and phytoremediation efficiency would be more complex than the effects of each individual factor.

The 'black box' of plant demography: how do seed type, climate and seed fungal communities affect grass seed germination?

Demographic studies measure drivers of plant fecundity including seed production and survival, but few address both abiotic and biotic drivers of germination such as variation in climate among sites, population density, maternal plants, seed type and fungal pathogen abundance. We examined germination and microbial communities of seeds of Danthonia californica, which are either chasmogamous (external, wind-pollinated) or cleistogamous (internal, self-fertilized) and Festuca roemeri, which are solely chasmogamous. Seed populations were sourced across environmental gradients. We tested germination and used high-throughput sequencing to characterize seed fungal community structure. For F. roemeri, maternal plants significantly influenced germination as did climate and pathogens; germination increased from wetter, cooler sites. For D. californica, the main drivers of germination were maternal plant, seed type and pathogens; on average, more chasmogamous seeds germinated. Fungal communities depended largely on seed type, with fewer fungi associated with cleistogamous seeds, but the communities also depended on site factors such as vapor pressure deficit, plant density and whether the seeds had germinated. Putative pathogens that were negatively correlated with germination were more abundant for both D. californica and F. roemeri chasmogamous seeds than D. californica cleistogamous seeds. In D. californica, cleistogamous and chasmogamous seeds contain vastly different fungal communities.

Transcriptional responses to water stress and recovery in a drought-tolerant fescue wild grass (Festuca ovina; Poaceae).

Water stress associated with drought-like conditions is a major factor limiting plant growth and impacts productivity of natural plant communities and agricultural crops. Molecular responses of plants to water stress have been studied most extensively in model species and crops, few of which have evolved natural drought tolerance. In the current study, we examined physiological and transcriptomic responses at multiple timepoints during increasing water stress and following initial recovery from stress in a drought-tolerant C3 species, Festuca ovina. Results demonstrated non-linear transcriptomic changes during increasing stress, but largely linear declines in physiological measurements during this same period. Transcription factors represented approximately 12.7% of all differentially expressed genes. In total, 117 F. ovina homologs of previously identified and molecularly characterized drought-responsive plant genes were identified. This information will be valuable for further investigations of the molecular mechanisms involved in drought tolerance in C3 plants.

Latitudinal gradients in population growth do not reflect demographic responses to climate.

Spatial gradients in population growth, such as across latitudinal or elevational gradients, are often assumed to primarily be driven by variation in climate, and are frequently used to infer species' responses to climate change. Here, we use a novel demographic, mixed-model approach to dissect the contributions of climate variables vs. other latitudinal or local site effects on spatiotemporal variation in population performance in three perennial bunchgrasses. For all three species, we find that performance of local populations decreases with warmer and drier conditions, despite latitudinal trends of decreasing population growth toward the cooler and wetter northern portion of each species' range. Thus, latitudinal gradients in performance are not predictive of either local or species-wide responses to climate. This pattern could be common, as many environmental drivers, such as habitat quality or species' interactions, are likely to vary with latitude or elevation, and thus influence or oppose climate responses.

Effects of nutrient addition on endophyte-associated grass invasion in a long-term, old-field community experiment.

Strictly vertically transmitted (hereditary) Epichloë spp. fungal endophytes are symbionts with cool-season pooid host grasses. Such endophytes may increase host invasiveness in the non-native, introduced ranges. However, because costs and benefits for the host can vary with the growing conditions, the endophyte may become locally or temporally extinct when costs outweigh benefits. Our long-term field experiment involved the introduction of seven Schedonorus pratensis (meadow fescue) cultivars hosting Epichloë uncinata endophyte, which represent host-grass populations differing in genetic backgrounds and Epichloë infection frequencies, to an unmanaged old field. In the first 6 years, the host grasses persisted but did not become invasive in the plant community, regardless of their endophyte infection frequency. Subsequently, we hypothesized that increasing nutrient availability would decrease endophyte costs and thus increase the host's success and abundance. We fertilized half of the plots for four additional years and re-examined S. pratensis invasiveness. We predicted that increased nutrient availability would increase S. pratensis abundance and E. uncinata frequency and concentration, as well as decrease plant community diversity, relative to unfertilized plots. Fertilization increased endophyte concentrations in three low-endophyte host populations. However, E. uncinata did not enable S. pratensis populations to achieve high abundance or to reduce plant community diversity in the old field, with or without fertilization. Thus, nutrient availabililty and host invasiveness appear to be decoupled in this study system.

Genome Resources for Seven Fungal Isolates That Cause Dollar Spot Disease in Turfgrass, Including Clarireedia jacksonii and C. monteithiana.

Fungi in the genus Clarireedia are widespread and destructive pathogens of grasses worldwide, and are best known as the causal agents of dollar spot disease in turfgrass. Here, we report genome assemblies of seven Clarireedia isolates, including ex-types of the two most widespread species, Clarireedia jacksonii and C. monteithiana. These datasets provide a valuable resource for ongoing studies of the dollar spot pathogens that include population diversity, host-pathogen interactions, marker development, and disease control.

Influence of Planting Density on the Phytoremediation Efficiency of Festuca arundinacea in cd-Polluted Soil.

Planting density can influence the biomass generation and element uptake capacity of various plants, which are two critical factors that determine the phytoremediation efficiency of plants. A series of 70 d experiments was performed to evaluate the influence of the planting density (10, 15, 20, 25, and 30 g seeds·m- 2, namely D10, D15, D20, D25, and D30, respectively) of Festuca arundinacea on the decontamination of Cd-polluted soils. The variations in the biomass yield, falling tissue (senescent and dead leaf tissues) proportion, and Cd extraction capacity of the species under different cultivation strategies were determined. The results showed that the biomass generation of the species per square meter increased as the planting density increased, reached a peak at D20, and then decreased significantly. In addition, planting density can change the proportions of different leaf types, and the highest amount of senescent and dead leaves which accumulated significantly more Cd compared with the emerging and mature leaf tissues was observed at D20. A suitable planting density can also drive the species to secrete more dissolved organic matter (DOM), especially hydrophilic fractionations in to the soil, activating more Cd. Therefore, the phytoremediation efficiency of the species was determined by the dry weight of the falling tissues, which contained more than 75% of the leaf Cd. A suitable planting density can enhance the Cd decontamination capacity of F. arundinacea, and the adjustment of the planting density is a practicable and economical method that can be performed in real fields.

Genome Resources for the Endophytic Fungus Paraphaeosphaeria sporulosa.

Paraphaeosphaeria genus includes plant pathogens or biocontrol agents as well as bioremediators and endophytic fungi. Paraphaeosphaeria sporulosa 10515 was isolated in 2013 as an endophyte of Festuca spp. collected on Mount Etna at 1,832 meters above sea level. Here, we present the first-draft whole-genome sequence of a P. sporulosa endophytic isolate. This data will be useful for future research on understanding the genetic bases of endophytism.

Efficient root metabolism improves drought resistance of Festuca arundinacea.

Festuca arundinacea is a model to work on the mechanisms of drought resistance in grasses. The crucial components of that resistance still remain not fully recognized. It was suggested that deep root system could be a crucial trait for drought avoidance strategy but the other components of root performance under water deficit have not paid much attention of scientists. In this study, two genotypes of F. arundinacea with a different ability to withstand soil water deficit were selected to perform comprehensive research, including analysis of root architecture, phytohormones, proteome, primary metabolome and lipidome under progressive stress conditions, followed by a rewatering period. The experiments were performed in tubes, thus enabling undisturbed development of root systems. We demonstrated that long roots are not sufficient to perfectly avoid drought damage in F. arundinacea and to withstand adverse environmental conditions without a disturbed cellular metabolism (with respect to leaf relative water potential and cellular membrane integrity). Furthermore, we proved that metabolic performance of roots is as crucial as its architecture under water deficit, to cope with drought stress via avoidance, tolerance and regeneration strategies. We believe that the presented studies could be a good reference for the other, more applied experiments, in closely related species.