Project description:Full-length transcriptome collection from Japanese larch (Larix kaempferi) and Dahurian larch (Larix gmelinii var. japonica) and identification of flowering signal genes
Project description:To investigate the roles of sRNAs in keeping embryo dormancy or germination in Larix leptolepis, we deciphered the endogenous "sRNAome" in dormant and germinated embryos. High-throughput sequencing of the sRNA libraries showed that dormant embryos exhibited a length bias towards 24-nt, while germinated embryos showed a bias towards a 21-nt and/or 22-nt length. Both of proportions for miRNAs to the non-redundant and redundant sRNAs were higher in germinated embryos than those in dormant embryos, while the ratio of unknown sRNAs was higher in dormant embryos than in germinated embryos. The proportion of 21-nt and 22-nt sRNAs increased in germinated embryos, which might attribute to the higher expression level of miRNAs. We identified a total of 160 conserved miRNAs from 39 families, 16 novel miRNAs, and 14 plausible miRNA candidates, of which novel and non-conserved known miRNAs might be the main contributors. These findings indicate that larch and possibly other gymnosperms have complex mechanisms of gene regulation involving sRNAs and miRNAs operating transcriptionally and post-transcriptionally during embryo dormancy and germination. One embryogenic cell line of Japanese larch (Larix leptolepis), designated as D878, with a high embryo maturation capacity was used in this study. Embryogenic callus were induced from immature embryos of larch on induction medium, followed by sub-culture, and culture on ABA-containing mature medium in a dark environment at 25 2 C. After cultured 45 days in mature medium, embryogenic calli developed into mature somatic embryos. In our study, the samples were harvested at day 57, one sample was collected after mature embryos continued to stay for 12 days on ABA-containing medium, and the other one was harvested after cultured for 12 days on ABA-removing medium. All samples were snap-frozen in liquid nitrogen, and stored in liquid nitrogen until RNA extraction.
Project description:Episodic drought stress negatively impacts the health of long-lived trees. Understanding the genetic and molecular mechanisms that underpin response to drought stress is requisite for selecting or enhancing climate change resilience. Here we aim to establish standardized drought stress protocols for transcriptome studies in poplar trees, to determine how hybrid poplars respond to prolonged and uniform exposure to drought; to determine if the responses to moderate and more severe growth-limiting drought stresses were qualitatively or quantitatively different; and, to determine how response to drought changes throughout the day. We established hybrid poplar trees (Populus x ’Okanese’) from unrooted stem cutting with abundant soil moisture for six weeks. We then withheld water to establish three soil water contents reflecting well-watered, moderate, and severe growth-limiting drought conditions. Plants were rewatered as needed for three weeks to maintain the soil water conditions. The mild and severe drought treatments elicited distinct changes in growth and development, photosynthetic rates and global transcriptomic changes. Notably, the time of day of sampling was strongest signal in the transcriptome data and it quantitatively and qualitatively affected drought responsive changes in gene expression. These analyses emphasize the complex nature of drought regulation in long-lived trees.
Project description:Purpose: The goal of this study are to reveal the internal mechanism of Bacillus pumilus G5 and silicon increased Glycyrrhiza uralensis Fisch. seedlings drought-tolerance by RNA-Seq. Methods: mRNA profiles of Glycyrrhiza uralensis Fisch. Seedling in five treatment: control treatment, drought stress treatment, drought stress with G5 treatment, drought stress with Si treatment and drought stress with G5 combined Si treatment. Results: The full-length transcriptome sequencing of 15 samples was completed, and the clean data of each sample was 6.28GB. All the consistent transcript sequences were aligned to the reference genome by minimap2 software and then de-redundant analysis was performed. Finally, 37267 genes were obtained. A total of 6934 DEGs were identified in four comparisons (D vs CK, DB vs D, DSi vs D, and DBSi vs D), among which are 967, 1559, 1278 and 3130 DEGs in four comparisons, respectively. Conclusions: Our study help to better understand the underlying molecular mechanisms of Bacillus pumilus G5 and silicon improve the drought-tolerance of G. uralensis.
Project description:To investigate the roles of sRNAs in keeping embryo dormancy or germination in Larix leptolepis, we deciphered the endogenous "sRNAome" in dormant and germinated embryos. High-throughput sequencing of the sRNA libraries showed that dormant embryos exhibited a length bias towards 24-nt, while germinated embryos showed a bias towards a 21-nt and/or 22-nt length. Both of proportions for miRNAs to the non-redundant and redundant sRNAs were higher in germinated embryos than those in dormant embryos, while the ratio of unknown sRNAs was higher in dormant embryos than in germinated embryos. The proportion of 21-nt and 22-nt sRNAs increased in germinated embryos, which might attribute to the higher expression level of miRNAs. We identified a total of 160 conserved miRNAs from 39 families, 16 novel miRNAs, and 14 plausible miRNA candidates, of which novel and non-conserved known miRNAs might be the main contributors. These findings indicate that larch and possibly other gymnosperms have complex mechanisms of gene regulation involving sRNAs and miRNAs operating transcriptionally and post-transcriptionally during embryo dormancy and germination.
Project description:Plants show a high degree of developmental plasticity in response to external cues, including day length and environmental stress. Water scarcity in particular can interfere with photoperiodic flowering, resulting in the acceleration of the switch to reproductive growth in several species, a process called drought escape. However, other strategies are possible and drought stress can also delay flowering, albeit the underlying mechanisms have never been addressed at the molecular level. We investigated these interactions in rice, a short day species in which drought stress delays flowering. A protocol that allows the synchronization of drought with the floral transition was set up to profile the transcriptome of leaves subjected to stress under distinct photoperiods. We identified clusters of genes that responded to drought differently depending on day length. Exposure to drought stress under floral-inductive photoperiods strongly reduced transcription of EARLY HEADING DATE 1 (Ehd1), HEADING DATE 3a (Hd3a) and RICE FLOWERING LOCUS T 1 (RFT1), primary integrators of day length signals, providing a molecular connection between stress and the photoperiodic pathway. However, phenotypic and transcriptional analyses suggested that OsGIGANTEA (OsGI) does not integrate drought and photoperiodic signals as in Arabidopsis, highlighting molecular differences between between long and short day model species.
Project description:By applying Illumina Novaseq 6000, Chlorella sp. TLD6B cells of the control group on day zero and 18, as well as under low salt stress (NaCl1) and under high salt stress (NaCl2) on day 18 were selected for transcriptome sequencing analysis. Meanwhile, 0.05 g/mL ( PEG1) and 0.1 g/mL PEG-6000 (medium for drought stress, PEG2 ) were used to prepare the drought-stressed Chlorella sp. TLD6B cells. Each treatment had two replicates. Clean data were filtered after the removal of adapters, poly-N strands, and low-quality reads. There were no reference genomes for Chlorella sp. TLD6B, and de novo assembly for clean reads was performed by using Trinity. The sequences were compared with databases such as NR, NT, Swiss-Pro, GO, KEGG, PFAM, and KOG using Blast X (e-value ≤ 10-5). The GO annotation of unigenes was obtained using BLAST2GO. FPKM method was used for the analysis of gene expression levels (Trapnell et al., 2010). Out of six samples, a total of 963,078,184 raw reads were generated. A total of 947,225,244 clean reads were obtained based on the base quality score and read length. Meanwhile, the GC percentage in clean reads reached nearly 66.0%, with Q20 being above 96%. A total of 219,577 transcripts with an average length of 1,394 bp were obtained. In total, 155,503 non-redundant unigenes were assembled for the following analyses. The length of the unigenes ranged from 200 bp to 23,825 bp, with an average length of 1,842 bp. Under different salt stress, verification had been conducted with qRT-PCR on nine unigenes of different pathways, which were related to lipid metabolism. The detection results by qRT-PCR were highly correlated with RNA-Seq results (r = 0.890, r2 = 0.791), which indicated that the RNA-Seq data of Chlorella sp. TLD6B under salt stress were accurate and reliable. Our study represents the first detailed analysis of Chlorella sp. TLD6B under salt stress transcriptomes. Hierarchical clustering of differentially expressed genes uncovered several currently uncharacterized genes that may contribute to the function about lipid accumulation of Chlorella sp. TLD6B under salt stress.
Project description:Small non-coding RNAs (sncRNAs) are emerging as key regulators of embryogenesis. To investigate the roles of sRNAs in regulating synchronism of somatic embryogenesis in Larix leptolepis, we deciphered the endogenous "sRNAome" in synchronous and desynchronous embryos. The 24-nt class sRNAs were overrepresented in both synchronous embryos and desynchronous embryos, accounting for 85.29% and 44.79%. A total of 29 miRNAs were upregulated in synchronous embryos, whereas 59 miRNAs were upregulated in desynchronous embryos. We describe the emerging theme for sncRNAs function: inhibiting the precocious expression, thus regulating the synchronism of somatic embryogenesis. These findings indicate that larch and possibly other gymnosperms have complex mechanisms of gene regulation involving sRNAs and miRNAs operating transcriptionally and post-transcriptionally during the regulation of synchronism. One embryogenic cell line of Japanese larch (Larix leptolepis), designated as D878, with a high embryo maturation capacity was used in this study. Embryogenic callus was induced from immature embryos of Japanese larch on induction medium followed by sub-culture. Calli at the proembryogenic mass III stage were cultured on maturation medium in a dark environment at 25 M-BM-1 2M-BM-0C. Samples were cultured on ABA-plus or ABA-minus maturation medium for 45 days. All samples were snap-frozen in liquid nitrogen, and stored in liquid nitrogen until RNA extraction.