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.
2021-12-20 | GSE191155 | GEO
Project description:Physiological Characteristic Changes and Full-Length Transcriptome of Artemisia sphaerocephala in Response to Drought Stress
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.