Project description:Abscisic acid (ABA) regulates plant development and adaptation to environmental conditions. The ABA biosynthesis pathway in plants has been thoroughly elucidated; however, very few transcription factors directly regulating the expression of ABA biosynthetic genes have been identified. Here we show that the tomato (Solanum lycopersicum) zinc finger transcription factor SlZFP2, which is mainly expressed in developing fruits and axillary buds, negatively regulates ABA biosynthesis. Overexpression of SlZFP2 resulted in multiple phenotypic changes, including more branches, early flowering, delayed fruit ripening, lighter seeds and faster seed germination, whereas gene silencing by RNA interference (RNAi) caused poor fruit set and inhibited seed germination. Gene expression analysis showed that SlZFP2 represses ABA biosynthesis mainly through downregulation of the ABA biosynthetic genes SITIENS (SIT), FLACCA (FLC) and aldehyde oxidase SlAO1. SlZFP2 delays the onset of ripening through suppression of the ripening regulator COLORLESS NON-RIPENING (CNR). Using bacterial one hybrid screening and a selected amplification and binding assay we identified the (A/T)(G/C)TT repeat as the core binding sequence of SlZFP2. We further identified a large number of tomato genes containing putative SlZFP2 binding sites in their promoter regions. Chromatin immunoprecipitation and electrophoretic mobility shift assays demonstrated that SIT, FLC and SlAO1 are direct targets of SlZFP2 through binding to their promoter regions. We propose that SlZFP2 represents a novel negative regulator for fine tuning ABA biosynthesis during fruit development and provides a potentially valuable tool for dissecting the role of ABA in fruit ripening.To gain further insight on transcriptome changes regulated by SlZFP2, we sequenced a representative SlZFP2 RNAi line in LA1589 background and its nontransgenic sibling (WT) on a Miseq platform. The RNAi line 207 showed defected fruit set and ABA biosynthesis were chosen for profiling gene expression via RNA sequencing. Its nontransgenic sibling was served as controls. Three biological replicates were conducted.
Project description:Abscisic acid (ABA) regulates plant development and adaptation to environmental conditions. The ABA biosynthesis pathway in plants has been thoroughly elucidated; however, very few transcription factors directly regulating the expression of ABA biosynthetic genes have been identified. Here we show that the tomato (Solanum lycopersicum) zinc finger transcription factor SlZFP2, which is mainly expressed in developing fruits and axillary buds, negatively regulates ABA biosynthesis. Overexpression of SlZFP2 resulted in multiple phenotypic changes, including more branches, early flowering, delayed fruit ripening, lighter seeds and faster seed germination, whereas gene silencing by RNA interference (RNAi) caused poor fruit set and inhibited seed germination. Gene expression analysis showed that SlZFP2 represses ABA biosynthesis mainly through downregulation of the ABA biosynthetic genes SITIENS (SIT), FLACCA (FLC) and aldehyde oxidase SlAO1. SlZFP2 delays the onset of ripening through suppression of the ripening regulator COLORLESS NON-RIPENING (CNR). Using bacterial one hybrid screening and a selected amplification and binding assay we identified the (A/T)(G/C)TT repeat as the core binding sequence of SlZFP2. We further identified a large number of tomato genes containing putative SlZFP2 binding sites in their promoter regions. Chromatin immunoprecipitation and electrophoretic mobility shift assays demonstrated that SIT, FLC and SlAO1 are direct targets of SlZFP2 through binding to their promoter regions. We propose that SlZFP2 represents a novel negative regulator for fine tuning ABA biosynthesis during fruit development and provides a potentially valuable tool for dissecting the role of ABA in fruit ripening.To gain further insight on transcriptome changes regulated by SlZFP2, we sequenced a representative SlZFP2 RNAi line in LA1589 background and its nontransgenic sibling (WT) on a Miseq platform.
Project description:In this study, we explored the metabolome and transcriptome of the ripe fruit in nine landrace accessions representing the seven genetic groups and compared them to the mature fruit of the wild progenitor S. pimpinellifolium. The goal is to shed light in understanding the factors responsible for acquiring tomato fruit quality (taste and flavour) at molecular level during the domestication process.
Project description:For exploring whether mRNA m6A modification participates in the regulation of tomato fruit ripening, we performed m6A-seq in three tomato fruit samples, including wild-type (WT) at 39 days post-anthesis (DPA) and 42 DPA, and Cnr mutant at 42 DPA, with three biological replicates. mRNA methylome analysis reveals that m6A methylation is a prevalent modification in mRNA of tomato fruit and the m6A sites are predominantly enriched in the stop codon and 3’ untranslated region, where m6A deposition has been proved to negatively correlate with gene expression. Hundreds of ripening-induced and ripening-repressed genes, including the SlDML2, were found to harbour changed m6A levels during fruit ripening or in the Cnr mutant, implicating the involvement of m6A modification in the regulation of fruit ripening.
Project description:Transcriptome analysis of 7 tissues of commercial tomato (S. lycopersicum cv MoneyMaker) and its wild red-fruited ancestor (S. pimpinellifolium LA0722) genotypes performed to assess expression level of tomato transcriptome and to aid whole genome annotation. Sequencing of fruit at 3 different developmental stages will help to assess gene regulation through ripening.
Project description:Here, we found that the tomato jmjC domain-containing gene SlJMJ6 encodes a histone lysine demethylase that specifically demethylates H3K27 methylation. Overexpression of SlJMJ6 accelerated fruit ripening in tomato, which is associated with the up-regulated expression of a large number of ripening-related genes. Integrated analysis of RNA-seq and ChIP-seq data identified 55 genes that are targeted directly by SlJMJ6 and transcriptionally up-regulated with decreased H3K27m3 in SlJMJ6 overexpressing (SlJMJ6-OE) fruits. A large number of the SlJMJ6-regulated genes are involved in transcription regulation, ethylene biosynthesis, cell wall degradation, pigment biosynthesis, and hormone signaling. Fourteen ripening-related genes including RIN, ACS4, ACO1, PL, TBG4 were confirmed to be directly regulated by SlJMJ6 through removing H3K27me3. Taken together, these results indicated that SlJMJ6 is a ripening prompting H3K27me3 demethylase that activates the expression of the ripening-related genes by modulating H3K27me3, thereby facilitating fruit ripening in tomato. To our knowledge, this is the first report of the involvement of a histone lysine demethylase in the regulation of fruit ripening.
Project description:Here, we found that the tomato jmjC domain-containing gene SlJMJ6 encodes a histone lysine demethylase that specifically demethylates H3K27 methylation. Overexpression of SlJMJ6 accelerated fruit ripening in tomato, which is associated with the up-regulated expression of a large number of ripening-related genes. Integrated analysis of RNA-seq and ChIP-seq data identified 55 genes that are targeted directly by SlJMJ6 and transcriptionally up-regulated with decreased H3K27m3 in SlJMJ6 overexpressing (SlJMJ6-OE) fruits. A large number of the SlJMJ6-regulated genes are involved in transcription regulation, ethylene biosynthesis, cell wall degradation, pigment biosynthesis, and hormone signaling. Fourteen ripening-related genes including RIN, ACS4, ACO1, PL, TBG4 were confirmed to be directly regulated by SlJMJ6 through removing H3K27me3. Taken together, these results indicated that SlJMJ6 is a ripening prompting H3K27me3 demethylase that activates the expression of the ripening-related genes by modulating H3K27me3, thereby facilitating fruit ripening in tomato. To our knowledge, this is the first report of the involvement of a histone lysine demethylase in the regulation of fruit ripening.
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.
Project description:Purpose: The goals of this study was to provide genome-wide data to investigate the molecular mechanism of ABA regulation in many ripening related biological processes, including fruit color variation, antioxidant capacity, flavonoids biosynthesis and photosynthesis. Methods:By applying the next generation sequencing technology, we conducted a comparative analysis of exogenous ABA and NDGA effects on tomato fruit maturation. Results:The high throughput sequencing results showed that 25728 genes expressed across all three samples, and 10388 of them were identified as significantly differently expressed genes (DEGs). Exogenous ABA was found to enhance the transcription of genes in pigments metabolism, including carotenoids biosynthesis and chlorophyll degradation, whereas NDGA treatment inhibited these progresses. The results also revealed the crucial role of ABA in flavonoids synthesis and regulation of antioxidant system. Intriguingly, we also found that an inhibition of endogenous ABA significantly enhanced the transcriptional abundance of genes involved in fruit photosynthesis. Conclusions:next-generation sequencing enabled us to characterize the transcriptomes of tomato fruit treated with ABA and NDGA. By comparing these transcriptomes with control respectively, we observed that ABA could accelerate fruit maturation by positively regulating many genes related to ripening processes. Our study have turned spotlight on the pathways of fruit pigmentation, including carotenoid biosynthesis and chlorophyll metabolism. Exogenous ABA was able to up-regulate many genes in relation to the carotenoids accumulation and chlorophyll breakdown, thus promoting the color transition of tomato fruit. In addition, ABA has the potential to improve the genes related to antioxidant capacity, such as SODs, CATs, APXs, GSTs, GPXs, TrXs and PrxRs. Besides, the expression changes of genes involved in flavonoids biosynthesis after ABA exposure was striking, suggesting ABA could enhance the defense response by producing more secondary metabolite in tomato fruit. Moreover, the sequencing results also implied high level of ABA could negatively affect photosynthesis of tomato fruit, which needs more investigations to explore the interaction between ABA and photosynthesis in the future.