Project description:To identify genes involved in the OsDIS1-mediated drought-responsive pathway, we performed microarray analysis of the OsDIS1 overexpression and wild-type plants under both normal and drought stress conditions using the Agilent rice Genechip. Seven-day-old plants of the OsDIS1 overexpression line 9-4-2 as well as the wild-type plants were used in the drought treatment. OsLEA3 was used as a positive control for the drought treatment. Genes with more than two-fold changes in the overexpression plants compared with the wild-type plants were selected. The expression pattern of some differentially expressed genes was further confirmed by real-time PCR.
Project description:Several homeobox genes belonging to HD-ZIP I subfamily are highly induced by drought stress at various developmental stages in rice. To analyze the role of a candidate HD-ZIP I subfamily member, OsHOX24, we constitutively overexpressed it in rice. The physiological analyses revealed that overexpression of OsHOX24 gene reduced drought stress tolerance in transgenic plants as compared to wild-type. We used microarrays to study the global effect of OsHOX24 overexpression in rice as compared to wild-type under control and drought stress condition.
Project description:High mobility group (HMG) proteins play an important role in regulation of gene transcription through modulate the structure of DNA. In this study, OsHMGB707, a HMG gene localized in rice drought resistance QTL interval, was isolated and the function on rice stress resistance was identified. Overexpression of OsHMGB707 significantly enhanced the drought resistance of the transgenic rice plants, whereas the OsHMGB707-RNAi transgenic rice plants exhibited slightly decrease in drought stress tolerance. To search the downstream genes regulated by OsHMGB707, we performed microarray analysis of the OsHMGB707-overexpressing, OsHMGB707-RNAi and wild-type plants under both normal conditions using Affymetrix Rice Genome Genechip. 21-day-old plants of the OsHMGB707-overexpressing line OE1, OsHMGB707-RNAi line RNAi1 as well as the wild-type plants were used in the normal condition.
Project description:In order to identify new miRNAs, NAT-siRNAs and possibly abiotic-stress regulated small RNAs in rice, three small RNA libraries were constructed from control rice seedlings and seedlings exposed to drought or salt stress, and then subjected to pyrosequencing. Totally three sets of small RNAs, which were obtained under normal condition as well as salt and drought stress conditions
Project description:To identify genes involved in the OsDIS1-mediated drought-responsive pathway, we performed microarray analysis of the OsDIS1 overexpression and wild-type plants under both normal and drought stress conditions using the Agilent rice Genechip. Seven-day-old plants of the OsDIS1 overexpression line 9-4-2 as well as the wild-type plants were used in the drought treatment. OsLEA3 was used as a positive control for the drought treatment. Genes with more than two-fold changes in the overexpression plants compared with the wild-type plants were selected. The expression pattern of some differentially expressed genes was further confirmed by real-time PCR. The OsDIS1 overexpression 9-4-2 plants and the wild-type plants were cultured on 1/2 MS medium plus 3% sucrose for seven days. About half of the plants were sampled as the untreated control for RNA isolation, and the rest were transferred with 1/2 MS medium onto filter papers to induce drought stress. When the leaves of the OsDIS1 overexpression plants began to show drought stress phenotypes, we collected leaves for RNA isolation. OsLEA3 was used as a positive control for the drought treatment.
Project description:GRAS transcription factors are plant-specific proteins that play diverse roles in plant development and abiotic stress responses, over-expression of OsGRAS23, a GRAS gene in rice, showed improved drought resistance. To search the downstream genes of OsGRAS23, we performed microarray analysis of the OsGRAS23-overexpressing and wild-type plants under both normal and drought stress conditions using Affymetrix Rice Genome Genechip. 21-day-old plants of the OsGRAS23-overexpressing line OE1 as well as the wild-type plants were used in the drought treatment.
Project description:Drought stress can cause huge crop production losses. Drought resistance consists of complex traits, and is regulated by arrays of unclear networks at the molecular level. A stress-responsive NAC transcription factor gene SNAC1 has been reported for its function in the positive regulation of drought resistance in rice, and several downstream SNAC1 targets have been identified. However, a complete regulatory network mediated by SNAC1 in drought response remains unknown. In this study, we performed Chromatin immunoprecipitation sequencing (ChIP-Seq) and RNA-Seq of SNAC1-overexpression transgenic rice (SNAC1-OE) lines and wild-type under normal and moderate drought stress conditions, to identify all SNAC1 target genes at a genome-wide scale by RNA-Seq analyses. We detected 980 differentially expressed genes (DEGs) in the SNAC1-OE lines compared to the wild-type control under drought stress conditions. By ChIP-Seq analyses, we identified 4,339 SNAC1-binding genes under drought stress conditions (SNAC1BGDs). By combining the DEGs and SNAC1BGDs, we identified 93 SNAC1-targeted genes involved in drought responses (SNAC1TGDs). Most SNAC1TGDs are involved in transcriptional regulation, response to water loss, and other processes related to stress responses. Moreover, the major motifs in the SNAC1BGDs promoters include a NAC recognition sequence (NACRS) and an ABA responsive element (ABRE). SNAC1-OE lines are more sensitive to ABA than wild-type. SNAC1 can bind to the OsbZIP23 promoter, an important ABA signaling regulator, and positively regulate the expression of several ABA signaling genes.
Project description:Plants capture solar energy and atmospheric carbon dioxide (CO2) through photosynthesis, which is the primary component of crop yield, and needs to be increased considerably to meet the growing global demand for food. Environmental stresses, which are increasing with climate change, adversely affect photosynthetic carbon metabolism (PCM) and limit yield of cereals such as rice (Oryza sativa) that feeds half the world. To study the regulation of photosynthesis, we developed a rice gene regulatory network and identified a transcription factor HYR (HIGHER YIELD RICE) associated to PCM, which on expression in rice enhances photosynthesis under multiple environmental conditions, determining a morpho-physiological program leading to higher grain yield (GY) under normal, drought and high temperature stress conditions. We show HYR is a master regulator, directly activating photosynthesis genes, cascades of transcription factors and other downstream genes involved in PCM and yield stability under drought and high temperature environmental stress conditions. To assess the role of increased HYR expression in rice, whole-genome microarrays were used to generate gene expression profiles of rice cultivar Nipponbare transformed with an overexpression construct of the HYR gene (Loc_Os03g02650) under control of the CaMV 35S promoter, along with control wild-type (WT) lines.
Project description:Dongxiang wild rice (Oryza rufipogon Griff.) is the progenitor of cultivated rice (Oryza sativa L.) and is well known for its superior level of tolerance against cold, drought and diseases. To date, however, little is known about the salt-tolerant character of Dongxiang wild rice. To elucidate the molecular genetic mechanisms of salt-stress tolerance in Dongxiang wild rice, the Illumina HiSeq 2000 platform was used to analyze the transcriptome profiles of the leaves and roots at the seedling stage under salt stress compared with those under normal conditions. The analysis results for the sequencing data showed that 6,867 transcripts were differentially expressed in the leaves (2,216 up-regulated and 4,651 down-regulated) and 4,988 transcripts in the roots (3,105 up-regulated and 1,883 down-regulated). Among these differentially expressed genes, the detection of many transcription factor genes demonstrated that multiple regulatory pathways were involved in salt stress tolerance. In addition, the differentially expressed genes were compared with the previous RNA-Seq analysis of salt-stress responses in cultivated rice Nipponbare, indicating the possible specific molecular mechanisms of salt-stress responses for Dongxiang wild rice. A large number of the salt-inducible genes identified in this study were co-localized onto fine-mapped salt-tolerance-related quantitative trait loci, providing candidates for gene cloning and elucidation of molecular mechanisms responsible for salt-stress tolerance in rice.
Project description:Floral organs are extremely sensitive to stress during anthesis and lead to severe yield loss. Rice anthers and pollinated pistils of two cultivars with contrasting tolerance to heat and drought stress under variable conditions, including control, heat, combined heat and drought stress, were used to explore gene expression pattern in male and female reproductive organs during anthesis under control and stress conditions. More gene regulation was induced by combined drought and heat stress than heat in anthers of both cultivars. N22 showed less regulation under combined stress than Moroberekan. The overlap of regulated genes between two cultivars was rather low, indicated the distinct molecular stress responses. We used whole genome microarrays to explore gene expression pattern and molecular mechanisms in male and female reproductive organs during anthesis under control and stress conditions in two rice cultivars, sought to identify the key transcripts that play roles in inducing heat and drought tolerance during reproduction in rice.