Fragaria Vesca Research Articles

Diversity and Functional Evolution of Terpene Synthases in Rosaceae.

Terpenes are organic compounds and play important roles in plant development and stress response. Terpene synthases (TPSs) are the key enzymes for the biosynthesis of terpenes. For Rosaceae species, terpene composition represents a critical quality attribute, but limited information is available regarding the evolution and expansion occurring in the terpene synthases gene family. Here, we selected eight Rosaceae species with sequenced and annotated genomes for the identification of TPSs, including three Prunoideae, three Maloideae, and two Rosoideae species. Our data showed that the TPS gene family in the Rosaceae species displayed a diversity of family numbers and functions among different subfamilies. Lineage and species-specific expansion of the TPSs accompanied by frequent domain loss was widely observed within different TPS clades, which might have contributed to speciation or environmental adaptation in Rosaceae. In contrast to Maloideae and Rosoideae species, Prunoideae species owned less TPSs, with the evolution of Prunoideae species, TPSs were expanded in modern peach. Both tandem and segmental duplication significantly contributed to TPSs expansion. Ka/Ks calculations revealed that TPSs genes mainly evolved under purifying selection except for several pairs, where the divergent time indicated TPS-e clade was diverged relatively anciently. Gene function classification of TPSs further demonstrated the function diversity among clades and species. Moreover, based on already published RNA-Seq data from NCBI, the expression of most TPSs in Malus domestica, Prunus persica, and Fragaria vesca displayed tissue specificity and distinct expression patterns either in tissues or expression abundance between species and TPS clades. Certain putative TPS-like proteins lacking both domains were detected to be highly expressed, indicating the underlying functional or regulatory potentials. The result provided insight into the TPS family evolution and genetic information that would help to improve Rosaceae species quality.

FvWRKY48 binds to the pectate lyase FvPLA promoter to control fruit softening in Fragaria vesca.

The regulatory mechanisms that link WRKY gene expression to fruit ripening are largely unknown. Using transgenic approaches, we showed that a WRKY gene from wild strawberry (Fragaria vesca), FvWRKY48, may be involved in fruit softening and ripening. We showed that FvWRKY48 is localized to the nucleus and that degradation of the pectin cell wall polymer homogalacturonan, which is present in the middle lamella and tricellular junction zones of the fruit, was greater in FvWRKY48-OE (overexpressing) fruits than in empty vector (EV)-transformed fruits and less substantial in FvWRKY48-RNAi (RNA interference) fruits. Transcriptomic analysis indicated that the expression of pectate lyase A (FvPLA) was significantly downregulated in the FvWRKY48-RNAi receptacle. We determined that FvWRKY48 bound to the FvPLA promoter via a W-box element through yeast one-hybrid, electrophoretic mobility shift, and chromatin immunoprecipitation quantitative polymerase chain reaction experiments, and β-glucosidase activity assays suggested that this binding promotes pectate lyase activity. In addition, softening and pectin degradation were more intense in FvPLA-OE fruit than in EV fruit, and the middle lamella and tricellular junction zones were denser in FvPLA-RNAi fruit than in EV fruit. We speculated that FvWRKY48 maybe increase the expression of FvPLA, resulting in pectin degradation and fruit softening.

Freezing induces an increase in leaf spectral transmittance of forest understorey and alpine forbs

Evergreen plants growing at high latitudes or high elevations may experience freezing events in their photosynthetic tissues. Freezing events can have physical and physiological effects on the leaves which alter leaf optical properties affecting remote and proximal sensing parameters. We froze leaves of six alpine plant species (Soldanella alpina, Ranunculus kuepferi, Luzula nutans, Gentiana acaulis, Geum montanum, and Centaurea uniflora) and three evergreen forest understorey species (Hepatica nobilis, Fragaria vesca and Oxalis acetosella), and assessed their spectral transmittance and optically measured pigments, as well as photochemical efficiency of photosystem II (PSII) as an indicator of freezing damage. Upon freezing, leaves of all the species transmitted more photosynthetically active radiation (PAR) and some species had increased ultraviolet-A (UV-A) transmittance. These differences were less pronounced in alpine than in understorey species, which may be related to higher chlorophyll degradation, visible as reduced leaf chlorophyll content upon freezing in the latter species. Among these understorey forbs, the thin leaves of O. acetosella displayed the largest reduction in chlorophyll (−79%). This study provides insights into how freezing changes the leaf optical properties of wild plants which could be used to set a baseline for upscaling optical reflectance data from remote sensing. Changes in leaf transmittance may also serve to indicate photosynthetic sufficiency and physiological tolerance of freezing events, but experimental research is required to establish this functional association.Graphical abstract

DNA Methylation Can Mediate Local Adaptation and Response to Climate Change in the Clonal Plant Fragaria vesca: Evidence From a European-Scale Reciprocal Transplant Experiment.

The ongoing climate crisis represents a growing threat for plants and other organisms. However, how and if plants will be able to adapt to future environmental conditions is still debated. One of the most powerful mechanisms allowing plants to tackle the changing climate is phenotypic plasticity, which can be regulated by epigenetic mechanisms. Environmentally induced epigenetic variation mediating phenotypic plasticity might be heritable across (a)sexual generations, thus potentially enabling rapid adaptation to climate change. Here, we assessed whether epigenetic mechanisms, DNA methylation in particular, enable for local adaptation and response to increased and/or decreased temperature of natural populations of a clonal plant, Fragaria vesca (wild strawberry). We collected ramets from three populations along a temperature gradient in each of three countries covering the southern (Italy), central (Czechia), and northern (Norway) edges of the native European range of F. vesca. After clonal propagation and alteration of DNA methylation status of half of the plants via 5-azacytidine, we reciprocally transplanted clones to their home locality and to the other two climatically distinct localities within the country of their origin. At the end of the growing season, we recorded survival and aboveground biomass as fitness estimates. We found evidence for local adaptation in intermediate and cold populations in Italy and maladaptation of plants of the warmest populations in all countries. Plants treated with 5-azacytidine showed either better or worse performance in their local conditions than untreated plants. Application of 5-azacytidine also affected plant response to changed climatic conditions when transplanted to the colder or warmer locality than was their origin, and the response was, however, country-specific. We conclude that the increasing temperature will probably be the limiting factor determining F. vesca survival and distribution. DNA methylation may contribute to local adaptation and response to climatic change in natural ecosystems; however, its role may depend on the specific environmental conditions. Since adaptation mediated by epigenetic variation may occur faster than via natural selection on genetic variants, epigenetic adaptation might to some degree help plants in keeping up with the ongoing environmental crisis.

Natural Variation in the Control of Flowering and Shoot Architecture in Diploid Fragaria Species.

In perennial fruit and berry crops of the Rosaceae family, flower initiation occurs in late summer or autumn after downregulation of a strong repressor TERMINAL FLOWER1 (TFL1), and flowering and fruiting takes place the following growing season. Rosaceous fruit trees typically form two types of axillary shoots, short flower-bearing shoots called spurs and long shoots that are, respectively, analogous to branch crowns and stolons in strawberry. However, regulation of flowering and shoot architecture differs between species, and environmental and endogenous controlling mechanisms have just started to emerge. In woodland strawberry (Fragaria vesca L.), long days maintain vegetative meristems and promote stolon formation by activating TFL1 and GIBBERELLIN 20-OXIDASE4 (GA20ox4), respectively, while silencing of these factors by short days and cool temperatures induces flowering and branch crown formation. We characterized flowering responses of 14 accessions of seven diploid Fragaria species native to diverse habitats in the northern hemisphere and selected two species with contrasting environmental responses, Fragaria bucharica Losinsk. and Fragaria nilgerrensis Schlecht. ex J. Gay for detailed studies together with Fragaria vesca. Similar to F. vesca, short days at 18°C promoted flowering in F. bucharica, and the species was induced to flower regardless of photoperiod at 11°C after silencing of TFL1. F. nilgerrensis maintained higher TFL1 expression level and likely required cooler temperatures or longer exposure to inductive treatments to flower. We also found that high expression of GA20ox4 was associated with stolon formation in all three species, and its downregulation by short days and cool temperature coincided with branch crown formation in F. vesca and F. nilgerrensis, although the latter did not flower. F. bucharica, in contrast, rarely formed branch crowns, regardless of flowering or GA20ox4 expression level. Our findings highlighted diploid Fragaria species as rich sources of genetic variation controlling flowering and plant architecture, with potential applications in breeding of Rosaceous crops.

Identification and characterization of strawberry FvGELP1 (Fragaria vesca GDSL esterase/lipase)

Abstract. Witasari LD, Huang FC, Schwab W. 2022. Identification and characterization of strawberry FvGELP1 (Fragaria vesca GDSL esterase/lipase).Biodiversitas 23: 907-915. Fruit softening is primarily the result of the hydrolytic enzymes activity. Esterases are reasonable candidates due to their putative role in cell wall components degradation. This study aimed to identify and characterize a new enzyme related to strawberry fruit ripening. Esterase activity was detected in the native PAGE of protein extract isolated from Fragaria ×ananassared fruit. Amino acid sequence analysis of the protein band revealed several esterases as possible candidates. GDSL esterase/lipase from Fragaria vesca(gene27964; FvGELP1) was chosen for cloning purposes and further analysis. Quantitative RT-PCR of FvGELP1in plant tissues of F. vescaindicated high expression levels in fruit, in particular in early developmental stages. The gene FvGELP1(1,161 bp) was amplified from F. vescafruit cDNA and expressed as a 43 kDa HisTag fusion protein in Saccharomyces cerevisiae.FvGELP1 possesses four conserved residues Gly43-Asp44-Ser45-Asn46. FvGELP1 contains Ser45, Asp364, and His367 as the catalytic triad. Esterase assays of FvGELP1 resulted in high levels of the aromatic alcohol products by applying ?-naphthyl acetate (?NA), p-nitrophenyl acetate (pNPA), phenyl acetate, and benzyl acetate as substrates. It could be suspected that FvGELP1 plays a role in strawberry fruit ripening and might be involved in the hemicellulose degradation, presumably by deacetylation of the polysaccharide.

Genome-wide identification and expression analysis of dirigent gene family in strawberry (Fragaria vesca) and functional characterization of FvDIR13

Dirigent proteins (DIR) are thought to have important roles in lignans or lignin-like molecules production, defensive responses, secondary metabolism, and disease resistance in plants. There is a lack of information about the DIR genes in strawberries (Fragaria vesca). In this study, 33 FvDIR genes were identified and divided into four subfamilies based on the phylogenetic analysis. A detailed bioinformatic analysis of FvDIR genes was performed including physiochemical properties of genes, chromosomal locations, exon-intron distribution, motif arrangements, in silico analysis of cis-elements, and protein localization. All the genes were unevenly distributed on 7 chromosomes. The structure and chromosomal distribution of FvDIR genes were systematically analyzed. Most of the genes showed conserved motif and domain composition within the same subfamily. According to exon-intron analysis, 85% of FvDIR genes have no intron. Evolutionary history analysis showed that tandem duplication (six sets) has played more roles in the expansion of gene family than segmental duplication (one set). In silico analysis of cis-elements suggested that most FvDIR genes may function in response to light, hormones, and environmental stresses. Furthermore, we analyzed the expression of FvDIR genes in different plants parts (roots, stolons, leaves, flowers, and fruits), against Colletotrichum gloeosporioides inoculation, and hormone (SA and JA) treatments. The majority of the genes displayed tissue-specific expression patterns, suggesting their roles in plant growth and development. Some of the genes showed differential expression against C. gloeosporioides inoculation and hormone (SA and JA) treatments, signifying their critical roles in plant response to pathogen and hormone treatments. Moreover, ectopic expression of FvDIR13 (Acc. NO. MZ318691) in Arabidopsis thaliana exhibited enhanced resistance to C. higginsianum, increase in lignin contents, and change in expression of genes having presumed roles in JA and SA signaling pathways. We surmise that FvDIR13 can promote lignin synthesis, and has roles in disease resistance via regulating JA and SA responsive genes. Our findings give a new foundation for understanding the functions of FvDIR genes and provide preliminary information about the roles of FvDIR13 in disease resistance.

Effect of Selected Meteorological Variables on Full Flowering of Some Forest Herbs in the Western Carpathians

At present, temperate forest ecosystems are endangered by both abiotic and biotic factors. The effects of abiotic components, e.g., meteorological variables, are constantly studied. However, the detailed mechanisms affecting the phenology of plants are still unknown. Two meteorological variables (air temperature and cumulative precipitation) were analysed for the period from 1995 to 2020 in order to determine which factor which has a more significant effect on onset of the full-flowering (FF) phenophase. A set of nine forest herbs, representing different phenological groups from the viewpoint of flowering, was examined (early spring: Petasites albus and Pulmonaria officinalis; mid-spring: Carex pilosa and Dentaria bulbifera; late spring: Fragaria visa and Galium odoratum; early summer: Veronica officinalis; mid-summer: Mycelis muralis; and late summer: Campanula trachelium). Temperature-sum requirements and temporal trends in the onset of FF were also studied. The research conducted at the Ecological Experimental Station in the Kremnické vrchy Mountains (central Slovakia) at an altitude of 500 m asl. Our results show that the air temperature correlated more significantly with the date of onset of FF (r > 0.6, p < 0.001) than with precipitation. On average, the air-temperature sums, calculated for the threshold temperatures of 0 °C and 5 °C, increased from 142.9 °C (Petasites albus) to 1732.9 °C (Campanula trachelium) and from 223.4 °C (Petasites albus) to 1820.8 °C (Campanula trachelium), respectively. Temporal trends in the onset of FF over the last 26 years confirm shifts to earlier dates for most species (excepting early spring Petasites albus). In spring flowering species, shifts ranged from 2 days (0.07 day/year) for Pulmonaria officinalis to 8 days (0.30 day/year) for Carex pilosa. As for summer species, the onset of flowering shifted more significantly to earlier dates—from 7 days (0.27 day/year) for Campanula trachelium to 12 days (0.46 day/year) for Veronica officinalis. The observed trends were statistically significant (p < 0.05) for five examined species (Carex pilosa, Dentaria bulbifera, Fragaria vesca, Veronica officinalis and Mycelis muralis).

Photodynamic Inactivation of plant pathogens part II: fungi

The constantly increasing demand for agricultural produce from organic and conventional farming calls for new, sustainable, and biocompatible solutions for crop protection. The overuse of fungicides leading to contamination of both produce and environment and the emergence of plant pathogenic fungi that are resistant to conventional treatments warrant the need for new methods to combat fungal infections in the field. We here deliver the follow-up study to our research on the Photodynamic Inactivation (PDI) of plant pathogenic bacteria (Glueck et al. in Photochem Photobiol Sci 18(7):1700–1708, 2019) by expanding the scope to fungal pathogens. Both fungal species employed in this study—Alternaria solani and Botrytis cinerea—cause substantial crop and economic losses. Sodium magnesium chlorophyllin (Chl, approved as food additive E140) in combination with Na2EDTA and the chlorin e6 derivative B17-0024 holding cationic moieties serve as eco-friendly photoactive compounds. Effectiveness of the antifungal PDI was measured by inhibition of growth of mycelial spheres (average diameter 2–3 mm) after incubation with the photosensitizer for 100 min and subsequent illumination using a LED array (395 nm, 106.6 J cm−2). One hundred micromolar Chl combined with 5 mM Na2EDTA was able to successfully photokill 94.1% of A. solani and 91.7% of B. cinerea samples. PDI based on B17-0024 can completely inactivate A. solani at 10 times lower concentration (10 µM); however, for B. cinerea, the concentration required for complete eradication was similar to that of Chl with Na2EDTA (100 µM). Using a plant compatibility assay based on Fragaria vesca, we further demonstrate that both photosensitizers neither affect host plant development nor cause significant leaf damage. The plants were sprayed with 300 µL of treatment solution used for PDI (one or three treatments on consecutive days) and plant growth was monitored for 21 days. Only minor leaf damage was observed in samples exposed to the chelators Na2EDTA and polyaspartic acid, but overall plant development was unaffected. In conclusion, our results suggest that sodium magnesium chlorophyllin in combination with EDTA and B17-0024 could serve as effective and safe photofungicides.Graphical abstract

Genome-wide identification and characterization of the bHLH gene family in an ornamental woody plant Prunus mume

The basic helix-loop-helix (bHLH) transcription factor family is the second-largest family in plants, where it plays essential roles in development, and the responses to multiple abiotic and biotic stressors. However, little information is available about this gene family in Prunus mume, which is widely cultivated in East Asia as an ornamental fruit tree. Here, 100 PmbHLH genes were identified, and their evolution and functions were explored in P. mume for the first time. The PmbHLH genes were classified into 21 subfamilies. The chromosomal distribution, physicochemical properties, bHLH domain, conserved motif, and intron/exon compositions were also analyzed. Furthermore, the evolutionary pattern, divergence time of the PmbHLH family, and genetic relationships among P. mume, Arabidopsis thaliana, and Prunus persica and Fragaria vesca of Rosaceae were explored. The functional prediction analysis of these PmbHLHs indicated that their functions varied, and included participating in the formation of organs and tissues, responding to stress, and the biosynthesis and metabolism of hormones and other secondary metabolites. Interestingly, expression analyses of PmbHLHs also revealed diverse expression patterns. Most of the PmbHLH genes were highly expressed in roots and stems, and a few were highly expressed in leaves, buds, and fruits, indicating tissue expression specificity. Eight PmbHLH genes, which were upregulated during low-temperature stress, may have critical roles in the response to cold stress. Ten PmbHLHs were differentially expressed between weeping and upright branches in a P. mume F1 population. These results shed light on the structure and evolution of the PmbHLH gene family, and lay a foundation for further functional studies of the bHLH genes.

MiR390-tasiRNA3-ARF4 pathway is involved in regulating flowering time in woodland strawberry.

miR390-tasiRNA3-ARF4 pathway was identified in woodland strawberry. FvemiR390 was involved in the regulation of flowering time, and miR390-tasiRNA3-ARF4 regulated flowering time through FveAP1/FveFUL in woodland strawberry. miRNA is an important type of regulator, and widely involved in plant growth, development and stress response. As a conserved miRNA family, the function of miR390 has been studied in many species, but poorly understood in woodland strawberry. In this study, we found that the members of miR390 family were highly conservative, and FvemiR390a and FvemiR390b have the same mature sequence. Therefore, we chose FveMIR390a to generate FvemiR390 mature sequence for functional studies. Subsequently, the result of transient gene expression assay proved that FvemiR390 negatively regulates FveARF4 through miR390-tasiRNA3-ARF4 pathway. Using transgenic plants, we discovered that the overexpression of FveMIR390a delayed flowering in woodland strawberry. Further studies revealed that the expressions of FveAP1 and FveFUL were lower in transgenic plants, which indicates miR390-tasiRNA3-ARF4 pathway delays flowering time through the FveAP1/FveFUL in woodland strawberry. Moreover, the expression of FvemiR390 responded to exogenous hormones, which also provides a reference for the application of exogenous hormones in regulating the flowering time of woodland strawberry.

DNA methylation dynamics during stress response in woodland strawberry (Fragaria vesca).

SummaryEnvironmental stresses can result in a wide range of physiological and molecular responses in plants. These responses can also impact epigenetic information in genomes, especially at the level of DNA methylation (5-methylcytosine). DNA methylation is the hallmark heritable epigenetic modification and plays a key role in silencing transposable elements (TEs). Although DNA methylation is an essential epigenetic mechanism, fundamental aspects of its contribution to stress responses and adaptation remain obscure.We investigated epigenome dynamics of wild strawberry (Fragaria vesca) in response to variable ecologically relevant environmental conditions at the DNA methylation level. F. vesca methylome responded with great plasticity to ecologically relevant abiotic and hormonal stresses. Thermal stress resulted in substantial genome-wide loss of DNA methylation. Notably, all tested stress conditions resulted in marked hot spots of differential DNA methylation near centromeric or pericentromeric regions, particularly in the non-symmetrical DNA methylation context. Additionally, we identified differentially methylated regions (DMRs) within promoter regions of transcription factor (TF) superfamilies involved in plant stress-response and assessed the effects of these changes on gene expression.These findings improve our understanding on stress-response at the epigenome level by highlighting the correlation between DNA methylation, TEs and gene expression regulation in plants subjected to a broad range of environmental stresses.

The callus formation capacity of strawberry leaf explant is modulated by DNA methylation.

Shoot regeneration from leaf tissue requires the de-differentiation of cells from a highly differentiated state into an actively dividing state, but it remains unclear how this physiological transition occurs and is regulated, especially at the epigenetic level. Here, we characterized the DNA methylome represented by 5-methylcytosine (5mC) in leaf and callus tissue derived from leaf explants of woodland strawberry, Fragaria vesca. We detected an overall increase in DNA methylation and distinct 5mC enrichment patterns in the CG, CHG, and CHH sequence contexts in genes and transposable elements. Our analyses revealed an intricate relationship between DNA methylation and gene expression level in leaves or leaf-derived callus. However, when considering the genes involved in callus formation and shoot regeneration, e.g. FvePLT3/7, FveWIND3, FveWIND4, FveLOG4 and FveIAA14, their dynamic transcription levels were associated with differentially methylated regions located in the promoters or gene bodies, indicating a regulatory role of DNA methylation in the transcriptional regulation of pluripotency acquisition in strawberry. Furthermore, application of the DNA methyltransferase inhibitor 5′-azacytidine (5′-Aza) hampered both callus formation and shoot regeneration from the leaf explants. We further showed that 5′-Aza downregulated the expression of genes involved in cell wall integrity, such as expansin, pectin lyase, and pectin methylesterase genes, suggesting an essential role of cell wall metabolism during callus formation. This study reveals the contribution of DNA methylation to callus formation capacity and will provide a basis for developing a strategy to improve shoot regeneration for basic and applied research applications.

Development of a single-cell atlas for woodland strawberry (Fragaria vesca) leaves during early Botrytis cinerea infection using single cell RNA-seq.

Pathogen invasion leads to fast, local-to-systemic signal transduction that initiates plant defense responses. Despite tremendous progress in past decades, aspects of this process remain unknown, such as which cell types respond first and how signals are transferred among cell types. Here, we used single-cell RNA-seq of >50 000 single cells to document the gene expression landscape in leaves of woodland strawberry during infection by Botrytis cinerea and identify major cell types. We constructed a single-cell atlas and characterized the distinct gene expression patterns of hydathode, epidermal, and mesophyll cells during the incubation period of B. cinerea infection. Pseudotime trajectory analysis revealed signals of the transition from normal functioning to defense response in epidermal and mesophyll cells upon B. cinerea infection. Genes related to disease resistance showed different expression patterns among cell types: disease resistance-related genes and genes encoding transcription factors were highly expressed in individual cell types and interacted to trigger plant systemic immunity to B. cinerea. This is the first report to document the single-cell transcriptional landscape of the plant pathogenic invasion process; it provides new insights into the holistic dynamics of host–pathogen interactions and can guide the identification of genes and the formulation of strategies for resistant cultivar development.

Genome-wide identification and analysis of SAUR gene family in strawberry (Fragaria vesca L.) reveal its potential functions in different developmental stages

Auxin is a plant hormone that is highly associated with various biological processes, especially plant growth, development and fruit ripening. The Small Auxin Upregulated RNA (SAUR) genes, whose family is the largest one of early auxin response genes, has received less attention from genome-wide analyzes compared to other gene families. In this study, we successfully conducted a genome-wide analysis of Fragaria vesca L. and identified 66 SAUR genes. In this paper, we provide important information on the identification of all SAUR genes in Fragaria vesca, including gene and protein sequences, chromosome mapping, and phylogeny analyzes. Gene expression data from the strawberry eFP Browser demonstrated that FvSAUR genes had diversified expression patterns in vegetative tissues. The RT-qPCR analysis demonstrated that 10 selected SAUR genes based on eFP strawberry browser could be expressed with expression divergence at least in one of the strawberry organs/tissues tested. Our analysis provides some basic genomic information for the FvSAUR genes in strawberry and a foundation for further investigations for deciphering their function during plant development and fruit ripening.

Assembly and annotation of <i>Fragaria vesca</i> 'Yellow Wonder' genome, a model diploid strawberry for molecular genetic research

<italic>Fragaria vesca</italic>, a wild diploid strawberry, serves as a fundamental research model for cultivated strawberry. The current reference genomes available are limited to two closely-related accessions, Hawaii 4 and CFRA2339. The widely-used model accession 'Yellow Wonder' does not yet have its reference genome. In this study, the genome of a 7^th generation inbred 'Yellow Wonder' was assembled using a combination of Oxford Nanopore long reads and Illumina short reads. The <italic>de novo</italic> chromosome-scale assembly of this 220 megabase genome possesses 34,007 genes which were annotated through lift over from the Hawaii 4 genome annotation. Genome comparisons show that the 'Yellow Wonder' genome is relatively distinct from the two previously published <italic>F. vesca</italic> accessions, Hawaii 4 and CFRA2339. The availability of a 'Yellow Wonder' reference genome adds another important genomic resource to <italic>Fragaria</italic> <italic>vesca</italic> and enables rapid research progress in strawberry.

FvZFP1 confers transgenic Nicotiana benthamiana resistance against plant pathogens and improves tolerance to abiotic stresses

Zinc finger proteins can induce plant resistance and activate the expression of molecules involved in the resistance pathway in response to harsh environmental conditions. Previously, we found that a novel Fragaria vesca zinc finger protein interacts with the P6 protein encoded by a strawberry vein banding virus. However, the molecular mechanism of the zinc finger protein in plant stress resistance is still unknown. In this study, we reported the identification and functional characterization of the RING finger and CHY zinc finger domain-containing protein 1 (FvZFP1). The overexpression of FvZFP1 in Nicotiana benthamiana enhanced resistance to tobacco mosaic virus (TMV) and Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) infection by increasing ROS content. Additionally, FvZFP1 overexpression upregulated salicylic acid (SA) response-related gene expression as well as SA accumulation following TMV and Pst DC3000 infection. Furthermore, FvZFP1 overexpression resulted in increased salinity and drought stress tolerance by increasing SOD activity and decreasing MDA content. Overexpression of FvZFP1 also activated the ABA pathway under salinity or drought conditions. To our knowledge, this is the first study on the involvement of F. vesca zinc finger protein in crosstalk between biotic and abiotic stress signaling pathways, suggesting that FvZFP1 is a candidate gene for the improvement of resistance in response to multiple stresses.

Prospecting the unpredicted potential traits of Cladophialophora chaetospira SK51 to alter photoperiodic flowering in strawberry, a perennial SD plant

Due to the economic importance of strawberry, many countries have established national breeding programs aimed at improving the flowering time and fruiting season to achieve year-round fruit availability. The ability of crops to produce fruits throughout the year with “flowering on command” is still a challenge in strawberry production systems. Although growth promotion by dark septate endophytic (DSE) fungi has been reported, the symbiotic association that alters flowering behaviors in photoperiodic fruit crops has not been studied. Here we established an experimental scheme for inducing the short-day (SD) strawberry cultivar Fragaria vesca to initiate flowering under a long-day (LD) photoperiod in symbiotic association with DSE fungus. We evaluated the relationship between growth-promoting and flower-inducing activities using Pearson's correlation analysis. Symbiotic association with C. chaetospira SK51 markedly stimulated SD strawberry cultivar to initiate early flowering, with the greatest flower induction (94.8%) and highest number of fruits (10.6 fruits/plant) during cultivation under a 16-h LD photoperiod at 23 °C, defined as non-flower-inductive conditions, considered as a new finding. We found that the interactions between C. chaetospira SK51 and strawberry plants markedly contributed to accelerating the earliness of the flowering time, as flower buds were initiated 90 days earlier than in the untreated control. Interestingly, we show that plant response in flowering by co-cultivation of C. chaetospira SK51 is constantly induce under various soil types and pHs. Based on Pearson's correlation coefficient analysis, we suggest that flowering behavior has a weakly non-significant relationship with growth-promoting activities, indicating that the control of flowering has a different or indirect pathway. Strawberry plants in symbiosis with C. chaetospira SK51 might be well-adapted to all regions and help preserve crops resilience against adverse climate conditions. These findings provide an essential resource and new insight for photoperiodic flowering research and innovation that can be adopted to deliver sustainable solutions that eventually will lead to extending and increasing crop production.

Ex Vivo Fecal Fermentation of Human Ileal Fluid Collected After Wild Strawberry Consumption Modulates Human Microbiome Community Structure and Metabolic Output and Protects Against DNA Damage in Colonic Epithelial Cells.

Wild strawberries (Fragaria vesca) are richer in (poly)phenols than common commercial strawberry varieties, e.g., Fragaria × ananassa. (Poly)phenols and their microbiota-derived metabolites are hypothesized to exert bioactivity within the human gut mucosa. To address this, the effects of wild strawberries are investigated with respect to their bioactivity and microbiota-modulating capacity using both in vitro and ex vivo approaches. Ileal fluids collected pre- (0h) and post-consumption (8h) of 225g wild strawberries by ileostomates (n = 5) and also in vitro digested strawberry varieties (Fragaria vesca and Fragaria × ananassa Duchesne) supernatants are collected. Subsequent fermentation of these supernatants using an in vitro batch culture proximal colon model reveals significant treatment-specific changes in microbiome community structure in terms of alpha but not beta diversity at 24 h. Nutri-kinetic analysis reveals a significant increase in the concentration of gut microbiota catabolites, including 3-(4hydroxyphenyl)propionic acid, 3-(3-hydroxyphenyl)propanoic acid, and benzoic acid. Furthermore, post-berry ileal fermentates (24 h) significantly (p< 0.01) decrease DNA damage (% Tail DNA, COMET assay) in both HT29 cells (∼45%) and CCD 841 CoN cells (∼25%) compared to untreated controls. Post berry consumption fermentates exhibit increased overall levels of (poly)phenolic metabolites, which retains their bioactivity, reducing DNA damage in colonocytes.

Characterization of YABBY genes and the correlation between their transcript levels and histone modifications in strawberry

YABBY (YAB) is a class of plant-specific transcription factors playing important roles in the growth and development of leaves and leaf-derived organs/tissues. The fleshy fruit of strawberry is developed from the expanded receptacle, a leaf-derived organ. In this study, we have identified six and 25 YAB proteins in the woodland strawberry (Fragaria vesca, 2n=2x=14) and the cultivated strawberry (Fragaria × ananassa, 2n=8x=56), respectively, and performed phylogenetic and structural analyses to characterize the YAB proteins. Transcriptome data demonstrate that FveYAB and FaYAB genes have temporal- and spatial-expression patterns in fruit development and ripening. Particularly, the transcript levels of FveYAB5 and its orthologous genes, FaYAB16 and FaYAB18, are up-regulated during ripening. Chromatin immunoprecipitation (ChIP) experiment reveals that FveYAB5, FaYAB16 and FaYAB18 are enriched in the active mark histone 3 lysine 9/lysine 14 acetylation (H3K9/K14ac) in the mature red fruits. Further, ChIP-seq profiles from the small white stage to the red stage reveal that FveYAB5 is positively correlated with H3K9/K14ac while negatively correlated with histone 3 lysine 27 tri-methylation, indicating a role of histone modifications in its transcriptional regulation. On the other hand, our transcriptome data reveal that the transcript levels of some FveYAB genes are responsive to temperature stress, in that FveYAB1, FveYAB2 and FveYAB5 are down-regulated after heat shock, while FveYAB1 and FveYAB5 are up-regulated after cold shock. In general, our work characterizes the YAB family proteins in terms of transcription patterns, association with histone modifications and responsiveness to temperature stress, which provides information for further functional studies.