Wild Strawberry Species Research Articles

Expression analysis of flowering gene in diploid wild strawberry species

Expression analysis of flowering gene in diploid wild strawberry species

Comparative analysis of the microbiomes of strawberry wild species Fragaria nilgerrensis and cultivated variety Akihime using amplicon-based next-generation sequencing.

Fragaria nilgerrensis is a wild strawberry species widely distributed in southwest China and has strong ecological adaptability. Akihime (F. × ananassa Duch. cv. Akihime) is one of the main cultivated strawberry varieties in China and is prone to infection with a variety of diseases. In this study, high-throughput sequencing was used to analyze and compare the soil and root microbiomes of F. nilgerrensis and Akihime. Results indicate that the wild species F. nilgerrensis showed higher microbial diversity in nonrhizosphere soil and rhizosphere soil and possessed a more complex microbial network structure compared with the cultivated variety Akihime. Genera such as Bradyrhizobium and Anaeromyxobacter, which are associated with nitrogen fixation and ammonification, and Conexibacter, which is associated with ecological toxicity resistance, exhibited higher relative abundances in the rhizosphere and nonrhizosphere soil samples of F. nilgerrensis compared with those of Akihime. Meanwhile, the ammonia-oxidizing archaea Candidatus Nitrososphaera and Candidatus Nitrocosmicus showed the opposite tendencies. We also found that the relative abundances of potential pathogenic genera and biocontrol bacteria in the Akihime samples were higher than those in the F. nilgerrensis samples. The relative abundances of Blastococcus, Nocardioides, Solirubrobacter, and Gemmatimonas, which are related to pesticide degradation, and genus Variovorax, which is associated with root growth regulation, were also significantly higher in the Akihime samples than in the F. nilgerrensis samples. Moreover, the root endophytic microbiomes of both strawberry species, especially the wild F. nilgerrensis, were mainly composed of potential biocontrol and beneficial bacteria, making them important sources for the isolation of these bacteria. This study is the first to compare the differences in nonrhizosphere and rhizosphere soils and root endogenous microorganisms between wild and cultivated strawberries. The findings have great value for the research of microbiomes, disease control, and germplasm innovation of strawberry.

Diversity of the volatilome and the fruit size and shape in European woodland strawberry (Fragaria vesca).

Woodland strawberry (Fragaria vesca subsp. vesca) is a wild relative of cultivated strawberry (F. × ananassa) producing small and typically conical fruits with an intense flavor and aroma. The wild strawberry species, F. vesca, is a rich resource of genetic and metabolic variability, but its diversity remains largely unexplored and unexploited. In this study, we aim for an in-depth characterization of the fruit complex volatilome by GC-MS as well as the fruit size and shape using a European germplasm collection that represents the continental diversity of the species. We report characteristic volatilome footprints and fruit phenotypes of specific geographical areas. Thus, this study uncovers phenotypic variation linked to geographical distribution that will be valuable for further genetic studies to identify candidate genes or develop markers linked to volatile compounds or fruit shape and size traits.

Evolutionary pattern of the presence and absence genes in Fragaria species

Presence and absence polymorphisms (PAPs) exist extensively and have been investigated in different organisms. However, PAPs have rarely been detected between strawberry species at the genome level. This study identified the presence and absence genes (P/A genes) between wild strawberry species (Fragaria vesca) and octoploid cultivated species (F. × ananassa) under a relatively strict criterion. In total, 333 P/A genes present in the wild strawberry but absent in the cultivated strawberry were detected. Of the P/A genes, 91.89% (306/333) were single genes, and only 8.11% were confirmed as multi-genes. The majority of the identified P/A genes in Fragaria were generated by tandem duplications. The P/A genes were unevenly distributed on the seven chromosomes of woodland strawberry, and they clustered preferentially near the telomeric regions of the chromosomes. The P/A genes tended to encode proteins with domains closely associated with responses to varying ecological factors, such as PPR, Protein kinases (PKs), NB-ARC, F-box and EF-hand domains. This indicated that the P/A genes were associated with coping with biotic and abiotic stresses to improve the adaptability of plants to changing environments.

Evolutionary history and pan-genome dynamics of strawberry (Fragaria spp.)

Strawberry (Fragaria spp.) has emerged as a model system for various fundamental and applied research in recent years. In total, the genomes of five different species have been sequenced over the past 10 y. Here, we report chromosome-scale reference genomes for five strawberry species, including three newly sequenced species' genomes, and genome resequencing data for 128 additional accessions to estimate the genetic diversity, structure, and demographic history of key Fragaria species. Our analyses obtained fully resolved and strongly supported phylogenies and divergence times for most diploid strawberry species. These analyses also uncovered a new diploid species (Fragaria emeiensis Jia J. Lei). Finally, we constructed a pan-genome for Fragaria and examined the evolutionary dynamics of gene families. Notably, we identified multiple independent single base mutations of the MYB10 gene associated with white pigmented fruit shared by different strawberry species. These reference genomes and datasets, combined with our phylogenetic estimates, should serve as a powerful comparative genomic platform and resource for future studies in strawberry.

Genetic diversity in wild species and cultivars of strawberry for the FanAAMT gene controlling fruit flavor volatiles

Background. An important consumer trait of strawberry fruits is their aroma. Methyl anthranilate makes a considerable contribution to the fruit flavor. The methyl anthranilate content in strawberry fruits is controlled by the FanAAMT (аnthranilic acid methyltransferase) gene. Identification of genetic determinants for this trait facilitates targeted selection of promising forms based on diagnostic DNA markers. The purpose of this study was to study the allelic diversity of the FanAAMT fruit flavor gene in wild strawberry species and strawberry cultivars for identification of promising genotypes.Materials and methods. The objects of this study were wild species of Fragaria L. as well as F. × anaschata Kantor. and F. × ananassa Duch. cultivars of different ecogeographic origin. The FanAAMT gene was identified with the dominant marker FanAAMT.Results and conclusion. In the analyzed collection of strawberry genotypes, the FanAAMT gene was identified in 36.4% of the forms, including the wild species F. vesca L., F. moschata Duch. and F. virginiana subsp. platypetala (Rydb.) Staudt, and cv. ‘Kupchikha’ (F. × anaschata). Among the analyzed F. × ananassa cultivars, the FanAAMT gene was found in 31.6% of the tested forms, specifically in 27.3% of the 22 Russian cultivars, and 37.5% of the analyzed foreign ones. Promising sources of high methyl anthranilate content in fruits were identified: wild spp. F. moschata, F. vesca, and F. virginiana subsp. platypetala; cv. ‘Kupchikha’ (F. × anaschata); Russian garden strawberry cvs. ‘Bylinnaya’, ‘Zenit’, ‘Lastochka’, ‘Neznakomka’, ‘Feyerverk’ and ‘Tsarskoselskaya’; and foreign garden strawberry cvs. ‘Karmen’, ‘Ostara’, ‘Samson’, ‘Symphony’, ‘Troubadour’ and ‘Vima Tarda’, in which the functional allele of the FanAAMT gene was found. In the remaining studied strawberry genotypes the marker FanAAMT was not detected, which presumably indicates that the FanAAMT gene is absent. cells (R9.4.1).

Early transcriptional response of terpenoid metabolism to Colletotrichum gloeosporioides in a resistant wild strawberry Fragaria nilgerrensis

Modern strawberry production is often threatened by microbe pathogens. Anthracnose is among the most prominent fungal disease caused mainly by Colletotrichum gloeosporioides and leads to large-scale losses both in quality and yield. Little is known regarding the mechanisms underlying the genetics in the strawberry-C. gloeosporioides interaction. In the current research, a wild accession ‘Fragaria nilgerrensis’ is used as a resistant model to study the roles of terpenoid and terpene genes in leaf response to C. gloeosporioides. We found that several terpenoids and terpene genes were up-regulated at early time points after challenged with C. gloeosporioides. Among the metabolites detected, sesquiterpenes were the most significantly accumulated compounds, increasing up to ~12-fold at 18 h post infection (hpi), followed by monoterpenes which showed a slight increase upon infection. Consistently, the time-resolved transcriptome data revealed that genes pertaining to terpenoid metabolism were rapidly up-regulated and co-expressed with signaling pathway genes relevant to defense response. Notably, quantitative real-time PCR confirmed that the expression of five terpene synthase genes (TPS) were greatly enhanced, by a factor of one to three orders of magnitude at 3–6 hpi. Our results reveal a possible link between rapidly induced terpenoid metabolism and the autoimmunity underlying anthracnose resistance in a wild strawberry species.

Current and Future Potential Distribution of Wild Strawberry Species in the Biodiversity Hotspot of Yunnan Province, China

Based on 243 current valid distribution records for six wild strawberry species in China and data on 20 environmental variables, the geographical distributions of and potentially suitable areas for the wild strawberry species in Yunnan Province (China) under the current climate scenario were explored using the MaxEnt model and ArcGIS software, and major environmental variables affecting their geographical distributions were evaluated. In addition, the spatio-temporal dynamic patterns of the suitable areas for the six wild strawberry species in Yunnan Province in the 2050s and 2070s under the two climate models of RCP2.6 and RCP8.5 were predicted. Under the current climate scenario, the six wild strawberry species have suitable areas in Yunnan Province, which were mainly distributed in the high-altitude and low-temperature regions in the northwest and northeast, such as Diqing and Zhaotong. In addition, the average size of the highly suitable area for diploid wild strawberry species was greater than that for tetraploid species. Under the future climate scenarios, the average size of the highly suitable area for diploid species showed a tendency to expand, while that of tetraploid species showed a tendency to shrink. Altitude was a critical variable affecting the distribution of tetraploid species. Under the two future climate models of RCP2.6 and RCP8.5, the suitable areas for wild strawberry species shifted to the regions of high latitude, high altitude, and low temperature. In addition, the average distance in the shift of the suitable area for tetraploid strawberry species was greater than that for the suitable area for diploid strawberry species. The above results provide valuable information for the management and protection of the germplasm resources of Fragaria.

Comparative analysis of fruit volatiles and related gene expression between the wild strawberry Fragaria pentaphylla and cultivated Fragaria × ananassa

Fragaria pentaphylla, one of several wild strawberry species, produces white or red fruits. The white fruits have a stronger aroma than the red. In this study, solid-phase microextraction was used in combination with gas chromatography–mass spectrometry to compare volatiles during fruit development and maturation from the two fruit types of F. pentaphylla and the cultivated F. × ananassa. A total of 38 volatile compounds were identified in F. × ananassa, while 61 and 53 volatile compounds were identified in the white and red fruits of F. pentaphylla, respectively. The predominant volatiles in white ripe fruits of F. pentaphylla were 3(2H)-furanone 4-methoxy-2,5 methyl (24.71%), butanoic acid, 2-methyl, methyl ester (10.43%), trans-2-hexenal (9.23%). The main volatiles in red ripe fruits of F. pentaphylla were 2-hexenal (21.23%), 1-hexanol (13.29%) and 2-hexen-1-ol acetate (13.00%). While the main volatiles in ripe fruits of F. × ananassa were butanoic acid, ethyl ester (25.80%), 2-hexenal (23.47%) and butanoic acid, 2-methyl (10.09%). In addition, cyclopropane propyl was first found in the white fruits of wild F. pentaphylla at high levels (4.83%). As the intense aroma of the white fruits of F. pentaphylla is characteristic of high 3(2H)-furanone 4-methoxy-2,5 methyl production. RNA-seq was used for quantitative analysis of volatiles-related gene expression. Integrative analysis of GC–MS data and RNA-seq data from fruits of F. pentaphylla indicated that reduction of sugar in red fruits of F. pentaphylla might lead to a relatively lower DMF and higher aldehydes and alcohols compared with that in white fruits.

The Genus Fragaria in Croatia

Only three native species of genus Fragaria (F. moschata, F. vesca and F. viridis) are recorded in three regions of Croatia. These species as well as many of their hybrids, are, or once were, cultivated for their edible fruits. The majority of cultivated strawberries in Europe belong to garden strawberries F. x ananassa (hybrids of F. chiloensis and F. virginiana). The most expanded wild strawberry species in Croatia is a woodland strawberry (F. vesca) whose berries are gathered seasonally as wild edible fruits. They often contain higher amount of nutrients and bioactive compounds in comparison to cultivated varieties. The research on the genus Fragaria species distribution in Croatia has not been carried out, and so is the case with many others wild growing fruit species in Croatia. By summing up a number of individual citations and observations, it is possible to get a perspective regarding the current state of their distribution.

Diversity of metabolite patterns and sensory characters in wild and cultivated strawberries1

In breeding programs wild strawberry species are used increasingly to enhance the genetic diversity and to implement higher sensory quality. Next to Fragaria moschata L. and F. viridis Weston wild collections cultivars of Fragaria vesca L. were the standards for strawberry taste in Europe before the development of Fragaria × ananassa Duch. around 250 years ago. Therefore, the objective of this research was the evaluation of patterns of volatile organic compounds including around twenty strawberry character impact compounds evaluated for Fragaria vesca and in comparison for standard cultivars of Fragaria × ananassa. The metabolic patterns were measured using immersion-SBSE-GC-MS. Sixteen accessions of Fragaria vesca exhibit a high diversity in qualities and quantities of volatile organic compounds (VOCs). A specific fruit sampling strategy equalizes environmental caused variation and avoids misleading interpretations. The shown results are valuable for further breeding activities regarding flavor, transcriptomic analyses, studies of biochemical pathways and signaling compounds as well as marker development.

Three wild Lithuanian strawberry species and their pollinators

The European wild strawberry species Fragaria vesca L., Fragaria viridis Weston, and Fragaria moschata Weston are sympatric and bloom concurrently, introducing the possibilities of cooperation and competition for pollinators. We studied the pollination biology of strawberries that were grown in rectangular plots at a field site near Vilnius city in Lithuania. The number of open flowers, the number of insects visiting flowers, and the plot area covered by strawberry plants were recorded. Wild strawberries were visited by solitary bees (38.5%), flies (31.4%), and other hymenopterans (21%; ants accounted for approximately 98% of this group). Coleopterans, lepidopterans and honey bees together represented less than 10% of the insects recorded on strawberries. Fragaria viridis and F. moschata flowers were more attractive to pollinators than those of F. vesca. The main visitors of F. viridis were small solitary bees; those of F. moschata were ants, while F. vesca flowers were visited by solitary bees, ants and flies in comparable numbers. We discuss competition for pollinators and the possible impact of climate fluctuation on strawberry-pollinator interactions.

Interspecific hybridization of diploids and octoploids in strawberry

Interspecific crosses were performed among accessions of the wild strawberry species F. vesca and F. nilgerrensis and the cultivated strawberry, F. × ananassa, following reciprocal crossing. Crosses between both F. vesca species ‘Hawaii-30’ and ‘UC-01’ were successful regardless of the presence of reciprocal crossing, while crosses with ‘Whiteberry’ of the F. nilgerrensis species were not successful. In particular, intraspecific hybridization of ‘Hawaii-30’ and ‘UC-01’ in the F. vesca species produced a tetraploid plant. Although octoploid ‘Akihime’ did not cross with different species, it performed well with ‘Hawaii-30’ only through the parent seed. Progenies of interspecific hybridization between species of different ploidy, namely ‘Hawaii-30’ and ‘Akihime’, produced 12 pentaploid plants with an intermediate phenotype between the crossing parents and characterized by sterility. In addition, despite its poor hybridization, a cross-combination between ‘Akihime’ and ‘Whiteberry’ produced one pentaploid plant, which did not bloom.

GEOGRAPHICAL DISTRIBUTION AND MORPHOLOGICAL DIVERSITY OF WILD STRAWBERRY GERMPLASM RESOURCE IN CHINA

Based on a systematical investigation, 11 species of Fragaria spp. have been described as distributed in China. There are eight diploid species including F. vesca L., F. nilgrrensis Schlecht., F. pentaphylla Lozinsk., F. gracilis A. Los., F. nubicola Lindl., F. viridis Duch., F. daltoniana J. Gay. and F. mandschurica Staudt., three tetraploid species, including F. orientalis Losinsk., F. moupinensis (Franch.) Card. and F. corymbosa A. Los. The wild strawberry species are mainly distributed in northeastern, northwestern and southwestern China. Among the 11 species, F. orientalis Losinsk. is distributed widely from Jilin to Hunan. F. nubicola Lindl. and F. daltoniana J. Gay. were only found in Tibet. F. viridis Duch., is originated in Xinjiang region. A pentaploid strawberry genotype was found in Changbai Mountains in northeast China. Morphological analysis of 58 wild strawberry genotypes native to China was done in the field. Among the 33 morphological traits, the fruit shape, petal shape, hair on pedicel and stolon, and calyx state showed great differences. The C.V. of most of morphological traits was between 21 % and 47%. But the C.V. of petal length, flower width, and length of hairs on petiole were below 20% and especially of fruit shape, reached 80.03%.

Potentilla reptansis an Alternative Host for Two Strawberry Viruses

Strawberry [Fragaria x ananassa Duchesne = Potentilla x ananassa (Rozier) Mabb] has accumulated a variety of viruses in its relatively short history. Strawberry crinkle virus and Strawberry mild yellow edge virus are transmitted obligately by the aphid Chaetosiphon fragaefolii (Cockerell), which also occasionally infests other species of Potentilla. Several wild strawberry species have been shown previously to be hosts of the viruses. Leaves infected with these strawberry viruses were grafted into plants of UC-5, an indicator strawberry cultivar, and then UC-5 leaves were grafted into Potentilla reptans. Leaves from P. reptans were subsequently grafted back to uninfected UC-5 plants to demonstrate their potential as reservoirs for the virus. UC-5, Fragaria vesca and P. reptans plants were indexed for strawberry viruses by end-point reverse transcriptase PCR subsequent to back grafting.

Decaploidy in Fragaria iturupensis (Rosaceae)

The strawberry genus, Fragaria (Rosaceae), has a base chromosome number of x = 7. Cultivated strawberries (F. ×ananassa nothosubsp. ananassa) are octoploid (2n = 8x = 56) and first hybridized from F. chiloensis subsp. chiloensis forma chiloensis × F. virginiana subsp. virginiana. Europe has no known native octoploid species, and only one Asian octoploid species has been reported: F. iturupensis, from Iturup Island. Our objective was to examine the chromosomes of F. iturupensis. Ploidy levels of wild strawberry species, include diploid (2n = 2x = 14), tetraploid (2n = 4x = 28), pentaploid (2n = 5x = 35), hexaploid (2n = 6x = 42), octoploid (2n = 8x = 56), and nonaploid (2n = 9x = 63). Artificial triploid (2n = 3x = 21), tetraploid, pentaploid, octoploid, decaploid (2n = 10x = 70), 16-ploid, and 32-ploid plants have been constructed and cultivated. Surprisingly, chromosome counts and flow cytometry revealed that F. iturupensis includes natural decaploid genotypes with 2n = 10x = 70 chromosomes. This report is the first of a naturally occurring decaploid strawberry species. Further research on F. iturupensis and exploration on northern Pacific islands is warranted to ascertain the phylogeny and development of American octoploid species.

Gain and Loss of Fruit Flavor Compounds Produced by Wild and Cultivated Strawberry Species

The blends of flavor compounds produced by fruits serve as biological perfumes used to attract living creatures, including humans. They include hundreds of metabolites and vary in their characteristic fruit flavor composition. The molecular mechanisms by which fruit flavor and aroma compounds are gained and lost during evolution and domestication are largely unknown. Here, we report on processes that may have been responsible for the evolution of diversity in strawberry (Fragaria spp) fruit flavor components. Whereas the terpenoid profile of cultivated strawberry species is dominated by the monoterpene linalool and the sesquiterpene nerolidol, fruit of wild strawberry species emit mainly olefinic monoterpenes and myrtenyl acetate, which are not found in the cultivated species. We used cDNA microarray analysis to identify the F. ananassa Nerolidol Synthase1 (FaNES1) gene in cultivated strawberry and showed that the recombinant FaNES1 enzyme produced in Escherichia coli cells is capable of generating both linalool and nerolidol when supplied with geranyl diphosphate (GPP) or farnesyl diphosphate (FPP), respectively. Characterization of additional genes that are very similar to FaNES1 from both the wild and cultivated strawberry species (FaNES2 and F. vesca NES1) showed that only FaNES1 is exclusively present and highly expressed in the fruit of cultivated (octaploid) varieties. It encodes a protein truncated at its N terminus. Green fluorescent protein localization experiments suggest that a change in subcellular localization led to the FaNES1 enzyme encountering both GPP and FPP, allowing it to produce linalool and nerolidol. Conversely, an insertional mutation affected the expression of a terpene synthase gene that differs from that in the cultivated species (termed F. ananassa Pinene Synthase). It encodes an enzyme capable of catalyzing the biosynthesis of the typical wild species monoterpenes, such as alpha-pinene and beta-myrcene, and caused the loss of these compounds in the cultivated strawberries. The loss of alpha-pinene also further influenced the fruit flavor profile because it was no longer available as a substrate for the production of the downstream compounds myrtenol and myrtenyl acetate. This phenomenon was demonstrated by cloning and characterizing a cytochrome P450 gene (Pinene Hydroxylase) that encodes the enzyme catalyzing the C10 hydroxylation of alpha-pinene to myrtenol. The findings shed light on the molecular evolutionary mechanisms resulting in different flavor profiles that are eventually selected for in domesticated species.

3種イチゴウイルスのイチゴ近縁野生植物における発生

3種イチゴウイルスのイチゴ近縁野生植物における発生