Project description:Comprehensive utilization of cottonseeds is limited by the presence of pigment gland and its inclusion gossypol. The ideal cotton is glandless-seeds and glanded-plant, a trait found in only few Australian wild cotton species, including Gossypium bickii. Introgressing the trait to cultivated species is proved to be difficult. Understanding the biological processes towards pigment gland morphogenesis and the associated underlying molecular mechanisms will facilitate breeding cultivated cotton varieties with the trait of glandless-seeds and glanded-plant. Single-cell RNA sequencing (scRNA-seq) was performed on 12,222 protoplasts isolated from cotyledons of germinating G. bickii seeds 48-hours after imbibition. Clustered into 14 distinct clusters unsupervisedly, these cells could be grouped into eight cell populations with the assistance of known cell marker genes. The pigment gland cells were well separated from others, and could be separated into pigment gland parenchyma cells, secretory cells, and apoptotic cells. In this study, integrating pigment gland cells developmental trajectory, transcription factors regulatory networks, and core transcription factors functional validation, a relatively complete model was proposed for pigment gland formation. Light and gibberellin were verified to promote the formation of pigment glands. Besides, three novel genes, GbiERF114 (ETHYLENE RESPONSE FACTOR 114), GbiZAT11 (ZINC FINGER OF ARABIDOPSIS THALIANA 11) and GbiNTL9 (NAC TRANSCRIPTION FACTOR-LIKE 9), were found to affect pigment gland formation. These findings shed new insights into pigment gland morphogenesis and lay the cornerstone for future cotton scRNA-seq investigations.
Project description:Comprehensive utilization of cottonseeds is limited by the presence of pigment gland and its inclusion gossypol. The ideal cotton is glandless-seeds and glanded-plant, a trait found in only few Australian wild cotton species, including Gossypium bickii. Introgressing the trait to cultivated species is proved to be difficult. Understanding the biological processes towards pigment gland morphogenesis and the associated underlying molecular mechanisms will facilitate breeding cultivated cotton varieties with the trait of glandless-seeds and glanded-plant. Single-cell RNA sequencing (scRNA-seq) was performed on 12,222 protoplasts isolated from cotyledons of germinating G. bickii seeds 48-hours after imbibition. Clustered into 14 distinct clusters unsupervisedly, these cells could be grouped into eight cell populations with the assistance of known cell marker genes. The pigment gland cells were well separated from others, and could be separated into pigment gland parenchyma cells, secretory cells, and apoptotic cells. In this study, integrating pigment gland cells developmental trajectory, transcription factors regulatory networks, and core transcription factors functional validation, a relatively complete model was proposed for pigment gland formation. Light and gibberellin were verified to promote the formation of pigment glands. Besides, three novel genes, GbiERF114 (ETHYLENE RESPONSE FACTOR 114), GbiZAT11 (ZINC FINGER OF ARABIDOPSIS THALIANA 11) and GbiNTL9 (NAC TRANSCRIPTION FACTOR-LIKE 9), were found to affect pigment gland formation. These findings shed new insights into pigment gland morphogenesis and lay the cornerstone for future cotton scRNA-seq investigations.
Project description:Purpose: The goal of this experiment was to use RNA-seq to compare the two commercial cotton species Gossypium hirsutum and Gossypium barbadense and determine what transcripts may account for the better fiber quality in the latter. Methods: RNA was extracted from Gossypium barbadense or Gossypium hirsutum fibers at 10, 15, 18, 21, and 28 days post anthesis. Paired-end, 100-bp RNA-seq was performed on an Illumina HiSeq2000 and the reads were mapped to the Gossypium raimondii genome at www.phytozome.net and non-homologous contig assemblies from Gossypium arboreum. Results from RNA-seq were combined with non-targeted metabolomics. Results: Approximately 38,000 transcripts were expressed (RPKM>2) in each fiber type and approximately 2,000 of these transcripts were differentially expressed in a cross-species comparison at each timepoint. Enriched Gene Ontology biological processes in differentially expressed transcripts suggested that Gh fibers were more stressed. Conclusions: Both metabolomic and transcriptomic data suggest that better mechanisms for managing reactive oxygen species contribute to the increased fiber length in Gossypium barbadense. This appears to result from enhanced ascorbate biosynthesis via gulono-1,4-lactone oxidase and ascorbate recycling via dehydroascorbate reductase.
Project description:Purpose: The goal of this experiment was to use RNA-seq to compare the two commercial cotton species Gossypium hirsutum and Gossypium barbadense and determine what transcripts may account for the better fiber quality in the latter. Methods: RNA was extracted from Gossypium barbadense or Gossypium hirsutum fibers at 10, 15, 18, 21, and 28 days post anthesis. Paired-end, 100-bp RNA-seq was performed on an Illumina HiSeq2000 and the reads were mapped to the Gossypium raimondii genome at www.phytozome.net and non-homologous contig assemblies from Gossypium arboreum. Results from RNA-seq were combined with non-targeted metabolomics. Results: Approximately 38,000 transcripts were expressed (RPKM>2) in each fiber type and approximately 2,000 of these transcripts were differentially expressed in a cross-species comparison at each timepoint. Enriched Gene Ontology biological processes in differentially expressed transcripts suggested that Gh fibers were more stressed. Conclusions: Both metabolomic and transcriptomic data suggest that better mechanisms for managing reactive oxygen species contribute to the increased fiber length in Gossypium barbadense. This appears to result from enhanced ascorbate biosynthesis via gulono-1,4-lactone oxidase and ascorbate recycling via dehydroascorbate reductase. See Bioproject PRJNA263926 and SRA accession SRP049330 for study design and raw sequencing data and Bioproject PRJNA269608 and TSA accession GBYK00000000 for Gossypium arboreum assembled contig sequences used for transcriptome mapping - Cotton fiber mRNA from 10,15,18,21 and 28 day post anthesis fiber from either Gossypium hirusutm or Gossypium barbadense was sequenced and differential gene expression analysis was conducted between species for each timepoint and between adjacent timepoints. Each timepoint was representative of fiber from 9 individual plants processed as 3 biological replicate pools (material from 3 individual plants per pool).