Project description:Rice (Oryza sativa L.) is a candidate crop for production of plant-based vaccines by genetic engineering technologies. MucoRice-CTB has been developed as a rice-seed-based vaccine against cholera by transgenic expression of modified cholera toxin B-subunit (CTB) under the RNA interference (RNAi)-mediated suppression of endogenous seed storage proteins. Here, we performed non-targeted metabolomic profiling of MucoRice-CTB to understand the overall effects of the genetic engineering on rice seed metabolism using gas chromatography/time-of-flight mass spectrometry.
Project description:Staple crops in human and livestock diets suffer from deficiencies in certain “essential” amino acids including methionine. With the goal of increasing methionine in rice seed, we generated a pair of “PushxPull” double transgenic lines, each containing a methionine-dense seed storage protein (2S albumin from sunflower, HaSSA) and an exogenous enzyme for either methionine (feedback desensitized cystathionine gamma synthase from Arabidopsis, AtD-CGS) or cysteine (serine acetyltransferase from E. coli, EcSAT) biosynthesis. In both double transgenic lines, the total seed methionine content was approximately 50% higher than in their untransformed parental line, Oryza sativa ssp. japonica cv. Taipei 309. HaSSA-containing rice seeds were reported to display an altered seed protein profile, speculatively due to insufficient sulfur amino acid content. However, here we present data suggesting that this may result from an overloaded protein folding machinery in the endoplasmic reticulum rather than primarily from redistribution of limited methionine from endogenous seed proteins to HaSSA. We hypothesize that HaSSA-associated endoplasmic reticulum stress results in redox perturbations that negatively impact sulfate reduction to cysteine, and we speculate that this is mitigated by EcSAT-associated increased sulfur import into the seed, which facilitates additional synthesis of cysteine and glutathione. The data presented here reveal challenges associated with increasing the methionine content in rice seed, including what may be relatively low protein folding capacity in the endoplasmic reticulum and an insufficient pool of sulfate available for additional cysteine and methionine synthesis. We propose that future approaches to further improve the methionine content in rice should focus on increasing seed sulfur loading and avoiding the accumulation of unfolded proteins in the endoplasmic reticulum.
Project description:We characterized the biological and molecular functions of AtC3H17, a unique Arabidopsis gene encoding a non-tandem CCCH zinc finger protein, in plant development. To investigate the downstream regulatory mechanisms of AtC3H17, whole genome microarray expression profiling was carried out. The experiment was designed to identify differentially expressed genes between WT and AtC3H17-overexpressing transgenic plants (AtC3H17 OXs) grown for 14 days under SD growth conditions. Interestingly, the most up-regulated genes were 12S seed storage globulin genes, CRUCIFERIN A (CRA1) and CRUCIFERIN 3 (CRU3), and seed oil-body protein genes such as OLEOSIN 1 (OLEO1) and OLEO2 in AtC3H17 OXs compared with WT. We performed quantitative RT-PCR and confirmed that transcription levels of CRU3, OLEO1, OLEO2, and 2S seed storage albumin 1 (At2S1) were higher in AtC3H17 OX seedlings than in WT seedlings.
Project description:Rice NF-YC11 is a transcription factor that plays a key regulatory role in storage substance accumulation during rice grain filling. To reveal the transcription regulatory network of NF-YC11 in rice, we performed genome-wide identification of NF-YC11 targets by immunoprecipitation sequencing (ChIP-seq) analyses in the NF-YC11-overexpression plants.
Project description:affy_rice_2011_03 - affy_compartimentation_rice_albumen_embryon - During germination, the rice seed goes from a dry quiescent state to an active metabolism. As with all cereals, the rice seed is highly differentiated between the embryo (that will give rise to the future plantlet) and the endosperm (that contains the seed storage compounds and that will degenerate). The molecular mechanisms operating in the rice seed embryo have begun to be described. Yet, very few studies have focused specifically on the endosperm during the germination process. In particular, the endosperm is mostly addressed with regards to its storage proteins but we have detected a large protein diversity by two-dimensional electrophoresis. Similarly, the endosperm is rich in total RNA which suggest that gene expression coming from seed maturation could play a role during the germination process. In this context, we want to compare the transcriptome of the embryo and the endosperm during rice seed germination. -We germinate rice seeds of the first sequenced rice cultivar i.e. Nipponbare during 0, 4, 8, 12, 16 and 24h of imbibition in sterile distilled water. Germination occurs under constant air bubbling, in the dark at 30°C. These rice seeds are then manually dissected into embryo and endosperm fractions. -The embryo-derived samples are abbreviated in “E” while the endosperm samples are abbreviated “A”. The germination time-point is indicated after the letter (e.g. E8 for embryo samples harvested after 8 hours of germination). Finally, the biological repetition number is indicated before the letter and the time digit (e.g. 1-E8 for an embryo sample from the first repetition at 8 hours of imbibition).
Project description:affy_rice_2011_03 - affy_compartimentation_rice_albumen_embryon - During germination, the rice seed goes from a dry quiescent state to an active metabolism. As with all cereals, the rice seed is highly differentiated between the embryo (that will give rise to the future plantlet) and the endosperm (that contains the seed storage compounds and that will degenerate). The molecular mechanisms operating in the rice seed embryo have begun to be described. Yet, very few studies have focused specifically on the endosperm during the germination process. In particular, the endosperm is mostly addressed with regards to its storage proteins but we have detected a large protein diversity by two-dimensional electrophoresis. Similarly, the endosperm is rich in total RNA which suggest that gene expression coming from seed maturation could play a role during the germination process. In this context, we want to compare the transcriptome of the embryo and the endosperm during rice seed germination. -We germinate rice seeds of the first sequenced rice cultivar i.e. Nipponbare during 0, 4, 8, 12, 16 and 24h of imbibition in sterile distilled water. Germination occurs under constant air bubbling, in the dark at 30M-BM-0C. These rice seeds are then manually dissected into embryo and endosperm fractions. -The embryo-derived samples are abbreviated in M-bM-^@M-^\EM-bM-^@M-^] while the endosperm samples are abbreviated M-bM-^@M-^\AM-bM-^@M-^]. The germination time-point is indicated after the letter (e.g. E8 for embryo samples harvested after 8 hours of germination). Finally, the biological repetition number is indicated before the letter and the time digit (e.g. 1-E8 for an embryo sample from the first repetition at 8 hours of imbibition). 36 arrays - rice; organ comparison,time course
Project description:Multiprotein complexes execute and coordinate diverse cellular processes such as organelle biogenesis, vesicle trafficking, cell signaling, and metabolism. Knowledge about their composition and localization provides useful clues about the mechanisms of cellular homeostasis and systems-level control. This is of great biological importance and practical significance in heterotrophic rice (Oryza sativa) endosperm and aleurone-subaleurone tissues, which are a primary source of seed vitamins and stored energy. Dozens of protein complexes have been implicated in the synthesis, transport, and storage of seed proteins, lipids, vitamins, and minerals. Mutations in protein complexes that control RNA transport result in aberrant endosperm with shrunken and floury phenotypes, significantly reducing seed yield and quality. The purpose of this study was to broadly predict protein complex composition in the aleurone-subaleurone layers of developing rice seeds using co-fractionation mass spectrometry. Following orthogonal chromatographic separations of biological replicates, thousands of protein elution profiles were subjected to distance-based clustering to enable large-scale multimerization state measurements and protein complex predictions. The predicted complexes had predicted functions across diverse functional categories, including novel heteromeric RNA binding protein complexes that may influence seed quality. This effective and open-ended proteomics pipeline provides useful clues about systems-level post-translational control during the early stages of rice seed development.
Project description:During seed growth, sugar and nitrogen compounds confer regulatory control on storage activities. Thus, seed storage production could be regulated by the supply of nutrients. In order to improve nitrogen flux into the embryo, transgenic pea lines were created where ADP-glucose pyrophosphorylase (AGP) from Pisum sativum has been repressed by RNAi approach in the seeds under control of the seed-specific LeB4 promotor (Bäumlein et al. Cis-analysis of a seed protein gene promoter: the conservative RY repeat CATGCATG within legumin box is essential for tissue-specific expression of a legumin gene. Plant J 1992 2: 233-239). The plastidial enzyme AGP catalyzes the reaction of glucose-1-phosphate and ATP to pyrophosphate and ADP-glucose, which is the substrate for starch synthase. The AGP activity and transcript levels were strongly decreased in three independent transgenic lines. Repression of AGP results in a wrinkled seed phenotype obviously due to transient accumulation of free sugars during maturation. Mature seeds have reduced starch content whereas the protein concentration is higher due to increased fractions of albumins and globulins. Repression of AGP interferes with storage protein metabolism and alters fluxes of nitrogen during seed growth. The influence of decreased AGP on altered gene expression in developing cotyledons was analysed using a 6k-Oligo-microarray. Ps6kOLI1 microarray hybridization were performed using three independent biological replicates of four developmental stages (20, 25, 30 and 35 DAP) from seeds of the transgenic line iAGP-3.
Project description:We characterized the biological and molecular functions of AtC3H17, a unique Arabidopsis gene encoding a non-tandem CCCH zinc finger protein, in plant development. To investigate the downstream regulatory mechanisms of AtC3H17, whole genome microarray expression profiling was carried out. The experiment was designed to identify differentially expressed genes between WT and AtC3H17-overexpressing transgenic plants (AtC3H17 OXs) grown for 14 days under SD growth conditions. Interestingly, the most up-regulated genes were 12S seed storage globulin genes, CRUCIFERIN A (CRA1) and CRUCIFERIN 3 (CRU3), and seed oil-body protein genes such as OLEOSIN 1 (OLEO1) and OLEO2 in AtC3H17 OXs compared with WT. We performed quantitative RT-PCR and confirmed that transcription levels of CRU3, OLEO1, OLEO2, and 2S seed storage albumin 1 (At2S1) were higher in AtC3H17 OX seedlings than in WT seedlings. Differentially expressed genes between WT and AtC3H17 OX at 14 days after germination under SD conditions (8-h-light and 16-h-dark cycle) were explored in whole genome level. Two AtC3H17 OX samples were compared to WT sample as a control.
Project description:One OsTudor-SN mutant, EM1084, carrying E503K point mutation and one associated WT-OsTSN complemented transgenic (pHL8042/EM1084 ) were applied in this study. EM1084 was obtained by TILLING studies (http://www.shigen.nig.ac.jp/rice/oryzabase). The E503K mutation site in EM1084 lies within the SN3 domain, while the EM1084 complemented transgenic plant was complemented with the full-length WT OsTSN gene driven by native OsTSN promoter. This mutation results in affecting storage protein mRNA localization and, in turn, with a strong reduction in grain weight and storage protein accumulation. Transcriptome analysis on the dehulled 10-14 days old developing seeds from wild type, EM1084 and pHL8042/EM1084 indicates that partial loss of Tudor-SN function caused the differential expression of storage protein genes and relevant genes involved in several essential biological processes during rice development.