Project description:The pink-flowered strawberry is very popular in China due to its appreciation and economic benefits and its flower has rich red petal with varying degrees, which is provided by anthocyanins accumulation. To better understand the functions of miRNAs, sRNAome, transcriptome and degradome sequencing were used to explore the target genes of miRNAs in flower development and coloring of pink-flowered strawberry. Nine small RNA libraries and a mixed degradome library from flower petals at different developmental stages were constructed and sequenced in this study. A total of 739 known miRNAs and 964 newly identified miRNAs were identified via small RNA sequencing, and their 2816 target genes were cleaved by 639 miRNAs based on the degradome data. There were 317 different expression miRNAs among flower development in pink-flowered strawberry regulated 2134 different expression target genes, which significantly enriched in the transcriptional regulation, phenylpropanoid biosynthesis and plant hormone signal transduction. Furthermore, integrated microRNAomic and transcriptomic analyses suggested that 98 miRNAs were targeted several transcription factors related to anthocyanin accumulation, in which 26 were targeted to MYBs, 12 bHLHs, 14 NACs, and 19 SPLs. And that, twenty seven different expression miRNAs may affect anthocyanin biosynthesis by regulating 23 targets participated in hormone signal transduction pathway in pink-flowered strawberry. The qRT-PCR analysis confirmed the expression changes of 21 miRNA-target pairs showed an opposite trend. Moreover, a co-expression regulatory network was constructed based on differentially expressed miRNA-targets according to the degradome data. Overall, we conducted a comparative analysis uncovered the regulatory functions of microRNAs in flower development and color changes of pink-flowered strawberry via multiple factors, including anthocyanin biosynthesis, hormone signaling and regulation factors. This work not only expands the knowledge of miRNAs affecting the coloration in strawberry, but also provides rich resources for future functional studies.
Project description:Pink-flowered strawberry is a new promising ornamental flower derived from intergeneric hybridization (Fragaria × Potentilla) with bright color, prolonged flowering period and edible fruits. However, the transcriptional events underlying anthocyanins biosynthesis pathway have not been fully characterized in its petal coloration. The pigment compounds accumulated in its fruits were the same as cultivated strawberry, but different from in its flowers. To gain insights into the regulatory networks related to anthocyanin biosynthesis and identify key genes, we performed an integrated analyses of the transcriptome and metabolomes involved in red petals at three development stages (Bud stage (L), Coloration beginning stage (Z) and Big bud stage (D)) of pink-flowered strawberry. Transcript and metabolite profiles were generated through high-throughput RNA-sequencing and high-performance liquid chromatography coupled with mass spectrometry, respectively. The results showed that the main pigments of red and dark pink petals were anthocyanins, among which cyanidins were the main compounds. There were no anthocyanins detected in white-flowered hybrids. A total of 50 285 non-redundant unigenes were obtained from the transcriptome databases, among which 59 differentially expressed genes could be identified as putative homologues of flower coloration related genes. Based on a comprehensive analysis relating pigmentation compounds to gene expression profiles, the mechanism of flower color formation was examined in pink-flowered strawberry. Furthermore, a new hypothesis explaining the lack of color phenotype of the white-flowered strawberry hybrids from the level of the transcriptome. The expression patterns of FpDFR gene and FpANS gene corresponded to the accumulation patterns of cyanidin contents in pink-flowered strawberry hybrids with different shades of pink; Whereas other anthocyanin biosynthesis genes were weakly related flower color deepened. Moreover, FpANS, FpBZ1 and FpUGT75C1 genes were the key factors that lead to the inability to accumulate anthocyanins in the white petals of PFS hybrids. Meanwhile, the competitive effect of FpFLS gene and FpDFR gene may further inhibit anthocyanin synthesis. The data presented herein are important for understanding of the molecular mechanisms underlying the petal pigmentation and will be powerful for integrating into novel genes that are potential targets for breeding new valuable pink-flowered strawberry cultivars.
Project description:In plants, microRNAs (miRNAs) play a critical role in post-transcriptional gene regulation and have been shown to control many genes involved in various biological and metabolic processes. Deep sequencing technologies have facilitated identification of species-specific or lowly expressed as well as conserved or highly expressed miRNAs in plants. Strawberry is one of the most economically important fruit throughout the world.Although miRNAs have been extensively studied in the past five years, limited systematic study of miRNAs has been performed on the Fragaria genus. These results show that regulatory miRNAs exist in agronomically important strawberry and may play an important role in strawberry growth, development, and response to disease.
Project description:In plants, microRNAs (miRNAs) play a critical role in post-transcriptional gene regulation and have been shown to control many genes involved in various biological and metabolic processes. Deep sequencing technologies have facilitated identification of species-specific or lowly expressed as well as conserved or highly expressed miRNAs in plants. Strawberry is one of the most economically important fruit throughout the world.Although miRNAs have been extensively studied in the past five years, limited systematic study of miRNAs has been performed on the Fragaria genus. These results show that regulatory miRNAs exist in agronomically important strawberry and may play an important role in strawberry growth, development, and response to disease. High throughput sequencing was employed to identify miRNAs in strawberry and try to describe their functions in strawberry growth and development
Project description:The wild strawberry Fragaria vesca has recently emerged as an excellent model for investigating flower and fruit traits in economically important fruit crops. Its history of physiological studies combined with sequenced genome and full complements of molecular genetic tools facilitate investigations into mechanisms of its unique biological processes such as fleshy fruit development from the enlarged stem tip called receptacle. Sequencing of nine small RNA libraries encompassing vegetative, flower, and fruit tissues led to the identification of 22 conserved and 10 less-conserved miRNAs as well as 41 novel miRNAs that are likely specific to the strawberry. High throughput Parallel Analyses of RNA ends (PARE) were performed to identify miRNA-guided cleavage events and corresponding target genes. We found that most conserved miRNAs developed species-specific target genes in addition to conserved targets, highlighting the dynamic and fluid nature of the miRNA_target relations. Significantly, we discovered two novel clusters of miRNAs, which together target up to 94 F-box genes. Within one of the clusters is a 22 nt novel miRNA, miRN39, that was expressed preferentially in the developing receptacle fruit and triggered phased siRNA production from six primary FBX PHAS loci. This miRN39-phasiFBX pathway may be involved in regulating disease resistance in the receptacle fruit. In addition, a modified “two-hit” mode of tasiRNA processing was identified in F. vesca, suggesting flexibility in applying previously set rules. A major theme that emerges from this work is that novel miRNAs and miRNA-phasiRNA networks may have evolved to regulate recently expanded gene families so as to control species-specific biological or physiological processes.
Project description:For exploring the influence of the m6A methyltransferase gene MTA silencing in the global m6A mRNA methylomes of strawberry fruits, we performed m6A-seq in the MTA RNAi strawberry fruits (RNAi-MTA) and the controls with three independently biological replicates. Results showed that MTA silencing induces the m6A hypomethylation of thousands of transcripts, including those of ripening and ABA pathway genes.
Project description:DNA methylation is a conserved epigenetic mark that influences diverse biological processes in many eukaryotes. Recently, DNA methylation was proposed to regulate fleshy fruit ripening. Fleshy fruits can be distinguished by their ripening process as climacteric fruits, such as tomatoes, or non-climacteric fruits, such as strawberries. Tomatoes undergo a global decrease in DNA methylation during ripening, due to increased expression of a DNA demethylase gene. The dynamics and biological relevance of DNA methylation during ripening of non-climacteric fruits, or other climacteric fruits, are unknown. Here, we generated and characterized single-base resolution maps of the DNA methylome in strawberry fruit, from immature to ripe stages. We observed an overall loss of DNA methylation during strawberry fruit ripening. Thus, ripening-induced DNA hypomethylation occurs not only in climacteric fruit, but also in non-climacteric fruit. However, we discovered that the mechanisms underlying DNA hypomethylation during ripening of tomato and strawberry are distinct. Unlike in tomatoes, DNA demethylase genes were not up-regulated during ripening of strawberries. Instead, genes involved in RNA-directed DNA methylation were down-regulated during strawberry ripening. Further, ripening-induced DNA hypomethylation was associated with decreased siRNA levels, consistent with reduced RdDM activity. Therefore, we propose that DNA hypomethylation during strawberry ripening is caused by diminished RdDM activity. Finally, hundreds of ripening-related genes displayed altered expression that was associated with, and thus potentially regulated by, DNA hypomethylation during ripening. Our findings provide new insight into the DNA methylation dynamics during the ripening of non-climateric fruit and reveal a novel function of RdDM in regulating an important process in plant development.
Project description:In contrast to climacteric fruits such as tomato, the knowledge on key regulatory genes controlling the ripening of strawberry, a non-climacteric fruit, is still limited. NAC transcription factors mediate different developmental processes in plants. Here, we identified and characterized FaRIF (Ripening Inducing Factor), a NAC transcription factor that is highly expressed and induced in strawberry receptacles during ripening. Functional analyses based on stable transgenic lines aimed at silencing FaRIF by RNA interference, either from a constitutive promoter or the ripe receptacle-specific EXP2 promoter, as well as overexpression lines showed that FaRIF controls critical ripening-related processes such as fruit softening and pigment and sugar accumulation. Physiological, metabolome and transcriptome analyses of receptacles of FaRIF-silenced and overexpression lines point to FaRIF as a key regulator of strawberry fruit ripening from early developmental stages, controlling abscisic acid (ABA) biosynthesis and signaling, cell wall degradation and modification, the phenylpropanoid pathway, volatiles production, and the balance of the aerobic/anaerobic metabolism. FaRIF is therefore a target to be modified/edited to control the quality of strawberry fruits.