Project description:Petal senescence is controlled by a complex regulatory network. Epigenetic regulation like histone modification influences chromatin state and gene expression. However, involvement of histone methylation in regulating petal senescence is still largely unknown. Here, we found that the trimethylation of histone H3 at Lysine 4 (H3K4me3) is increased during the ethylene induced petal senescence in carnation (Dianthus caryophyllus L.). The H3K4me3 levels are positively associated with the expression of transcription factor DcWRKY75, ethylene biosynthetic genes DcACS1 and DcACO1, and senescence associated genes (SAGs) DcSAG12 and DcSAG29. Further, we identified that carnation DcATX1 (ARABIDOPSIS HOMOLOG OF TRITHORAX1) encodes a histone lysine methyltransferase which can methylate H3K4. Knockdown of DcATX1 delays ethylene induced petal senescence in carnation, which is associated with the downregulated expression of DcWRKY75, DcACO1 and DcSAG12. While overexpression of DcATX1 exhibits the opposite effects. DcATX1 promotes the transcription of DcWRKY75, DcACO1 and DcSAG12 by targeting to their promoters to elevate the H3K4me3 levels. Overall, our results demonstrate that DcATX1 is a H3K4 methyltransferase that promotes the expression of DcWRKY75, DcACO1, DcSAG12 and maybe other downstream target genes by regulating H3K4me3 levels, thereby accelerating ethylene induced petal senescence in carnation. This study further indicates that epigenetic regulation is important for plant senescence process.
Project description:Small RNA libraries were constructed from total RNA from Jasminum sambac plants exhibiting virus-like symptoms. After sequencing, small RNAs were assembled into contigs with MetaVelvet and assembled contigs were aligned against the NR database of NCBI using BLASTx. Top hits that reported a virus as subject were considered putative viral sequences. Based on such alignments, the whole genome of a virus, we tentatively name Jasmine Virus H was recovered and cloned. Two more small RNA libraries were made in a confirmatory experiment. One from Jasminum sambac and another one from Nicotiana benthamiana plants infected with the newly-cloned virus. The small RNA libraries were aligned against the full-length sequence of Jasmine Virus H to determine the spacial distribution of virus-derived small RNAs along the virus genome.
Project description:During the process of flower opening, most petals move downward in the direction of pedicel (i.e., epinastic movement). In most Delphinium flowers, however, their two lateral petals display a very peculiar movement, the mirrored helical rotation. Such a distinctive petal movement requires the twist of the stalk. However, in some lineages, their lateral petals also exhibit asymmetric bending that increases the degree of mirrored helical rotation, facilitating the formation of a 3D final shape. Notably, the petal asymmetric bending is a novel trait that has not been noticed yet so that its morphological nature, developmental process and molecular mechanisms remain largely unknown. Here, by using D. anthriscifolium as a model, we determined that the petal asymmetric bending was caused by localized expansion of cell width, accompanied with specialized arrangement of surface ornamentation, on the adaxial epidermis. Digital gene analyses, gene expression and functional studies revealed that a class I homeodomain-leucine zipper family transcription factor gene, DeanLATE MERISTEM IDENTITY1 (DeanLMI1), contributes to the petal asymmetric bending; knockdown of it led to the formation of explanate 2D petals. Specifically, DeanLMI1 promotes cell expansion in width and influences the arrangement of surface ornamentation, through regulating the auxin distribution, on the localized adaxial epidermis. These results not only provide a comprehensive portrait of petal asymmetric bending for the first time, but also shed some new insight into the mechanisms of flower opening and helical movement in plants.
Project description:Petal senescence involves numerous programmed changes in biological and biochemical processes. Ubiquitination plays a critical role in protein degradation, a hallmark of organ senescence. Therefore, we investigated changes in the proteome and ubiquitome of senescing rose (Rosa hybrida) petals to better understand their involvement in petal senescence. Of 3859 proteins quantified in senescing petals, 1198 were up-regulated and 726 were down-regulated during senescence. We identified 2208 ubiquitinated sites including 384 with increased ubiquitination in 298 proteins and 1035 with decreased ubiquitination in 674 proteins. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed that proteins related to peptidases in proteolysis and autophagy pathways were enriched in the proteome, suggesting that protein degradation and autophagy play important roles in petal senescence. In addition, many transporter proteins accumulated in senescing petals, and several transport processes were enriched in the ubiquitome, indicating that transport of substances is associated with petal senescence and regulated by ubiquitination. Moreover, several components of the brassinosteroid (BR) biosynthesis and signaling pathways were significantly altered at the protein and ubiquitination levels, implying that BR plays important roles in petal senescence. Our data provide a comprehensive view of rose petal senescence at the posttranslational level.
2020-05-27 | PXD016490 | Pride
Project description:Multi-species Single Cell Data Process Pipeline