C4 Photosynthesis: Gene expression in mesophyll and bundle sheath cells of bundle sheath defective2 mutant
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ABSTRACT:
ORGANISM(S): Zea mays
PROVIDER: GSE13758 | GEO | 2018/04/30
REPOSITORIES: GEO
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Project description:During Zea mays (maize) C4 differentiation, mesophyll (M) and bundle sheath (BS) cells accumulate distinct sets of photosynthetic enzymes, with very low photosystem II (PSII) content in BS chloroplasts. Consequently, there is little linear electron transport in the BS and ATP is generated by cyclic electron flow. In contrast, M thylakoids are very similar to those of C3 plants and produce the ATP and NADPH that drive metabolic activities. Regulation of this differentiation process is poorly understood but involves expression and coordination of nuclear and plastid genomes. Here, we identify a recessive allele of the maize Hcf136 homologue that in Arabidopsis thaliana functions as a PSII stability or assembly factor located in the thylakoid lumen. Proteome analysis of the thylakoids and electron microscopy reveal that Zm hcf136 lacks PSII complexes and grana thylakoids in M chloroplasts, consistent with the previously defined Arabidopsis function. Interestingly, hcf136 is also defective in processing the full-length psbB-psbT-psbH-petB-petD polycistron specifically in M chloroplasts. To determine whether the loss of PSII in M cells affects C4 differentiation, we performed cell-type specific transcript analysis of hcf136 and wild-type seedlings. The results indicate that M and BS cells respond uniquely to the loss of PSII, with little overlap in gene expression changes between data sets. These results are discussed in the context of signals that may drive differential gene expression in C4 photosynthesis. To explore the disruption of PSII activity on gene expression, transcript profiles from separated M and BS cells were examined using two-label microarray analysis. Total RNA was isolated from the second leaves of mutant and wild-type silbings. Six biological replicates were used to compare wild-type and mutant transcript profiles in separate M and BS experiments. To maximize biological replication, different seedling pools were used for each of the 12 hybridizations. Microarray experiments and analyses were performed using the Genisphere MPX900 kit and the Maize Array Consortium oligonucleotide platform (GPL5439; GPL5440). Feature intensity values were log-transformed and corrected for local background signal, and a LOWESS procedure (Dudoit et al., 2002) was used to normalize between channels. Features with either low or saturating signal intensity were discarded from further analysis. High expression filtering was less stringent to avoid elimination of previously characterized, high abundance, C4 cell-specific transcripts. After filtering, features that were not assigned an MZ number by the Maize Array Consortium were discarded from further analysis. The moderated t-test (Smyth, 2004) using the R package limma was applied to identify differentially expressed genes. The p-values for each test (gene) were converted to q-values for false discovery rate analysis as described by Storey et al. (2004). To avoid confounding treatment effects associated with direct comparisons of M and BS transcriptomes (Sawers et al., 2007), comparisons were only made using the same cell type across the hcf136 and wild-type sibling genotypes. Bundle sheath (BS) Samples: GSM245063-GSM245164 Mesophyll (M) Samples: GSM245165 - GSM245206
2008-01-31 | E-GEOD-9698 | biostudies-arrayexpress
Project description:Triplicate replicates of bundle sheath and mesophyll cell RNAseq from the C4 grass Sorghum bicolor.
2016-06-06 | E-MTAB-4021 | biostudies-arrayexpress
Project description:Maize, as a C4 plant, possesses two distinct types of photosynthetic cells, the mesophyll (M) and the bundle sheath (BS) cells. To elucidate their functional and regulatory differentiation we isolated large quantities of highly homogeneous M and BS cells from new mature leaves for transcriptome profiling by Illumina sequencing. More than 100,000,000 reads for each cell type were mapped to the maize genome, revealing 44,964 expressed genes. Among these, 37,105 genes were expressed in M cells, including 423 M-enriched genes and 20 M-enriched transcription factor (TF) genes, whereas 42,782 genes were expressed in BS cells, including 771 BS-enriched genes and 75 BS-enriched TF genes. Pathway analyses revealed cell differentiation in various cellular activities, with M cells playing more important roles in light reaction, protein synthesis, abiotic stress, tetrapyrrole synthesis and RNA-RNA binding, while BS cells specializing in transport, signaling, protein degradation, major C metabolism, and the Calvin cycle. Genes coding for enzymes and transporters involved in photosynthesis exhibit a strong cellular preference in expression. To a lesser extent, cell differentiation also occurs in genes involved in the metabolism of starch, sucrose, nitrogen, sulfur, amino acid, and secondary metabolites. This comprehensive dataset will be useful for studying the regulation and evolution of C4-specific and related genes.
2012-09-18 | E-MTAB-4320 | biostudies-arrayexpress
Project description:Bundle sheath and mesophyll cell RNAseq profiling
| PRJEB11652 | ENA
Project description:Leaves are asymmetric, with differential functionalization of abaxial and adaxial tissues. The bundle sheath (BS) surrounding the vasculature of the C3 crop barley is dorsoventrally differentiated into three domains: adaxial structural, lateral S-type, and abaxial L-type. S-type cells seem to transfer assimilates towards the phloem. Here we used single-cell RNA sequencing to investigate BS differentiation in C4 maize. Abaxial BS (abBS) cells of rank-2 intermediate veins specifically expressed three SWEET sucrose uniporters (SWEET13a, b, and c) and UmamiT amino acid efflux transporters. SWEET13a, b, c were also identified in the phloem parenchyma (PP). Thus maize acquired a unique mechanism for phloem loading in which abBS cells provide the main pathway for apoplasmic sucrose transfer towards the phloem. This pathway predominates in veins responsible for phloem loading (rank-2 intermediate), while rank-1 intermediate and major veins export sucrose from the phloem parenchyma (PP) adjacent to the sieve element companion cell (SE/CC) complex, as in Arabidopsis. We surmise that abBS identity is subject to dorsoventral patterning and has components of PP identity. The observations provide first insights into the unique properties of abBS cells, cells previously considered to fulfill the same functions as other bundle sheath cells (BSCs), and a basis for understanding the C4 syndrome.
2021-03-02 | GSE157757 | GEO
Project description:Leaves are asymmetric, with differential functionalization of abaxial and adaxial tissues. The bundle sheath (BS) surrounding the vasculature of the C3 crop barley is dorsoventrally differentiated into three domains: adaxial structural, lateral S-type, and abaxial L-type. S-type cells seem to transfer assimilates towards the phloem. Here we used single-cell RNA sequencing to investigate BS differentiation in C4 maize. Abaxial BS (abBS) cells of rank-2 intermediate veins specifically expressed three SWEET sucrose uniporters (SWEET13a, b, and c) and UmamiT amino acid efflux transporters. SWEET13a, b, c were also identified in the phloem parenchyma (PP). Thus maize acquired a unique mechanism for phloem loading in which abBS cells provide the main pathway for apoplasmic sucrose transfer towards the phloem. This pathway predominates in veins responsible for phloem loading (rank-2 intermediate), while rank-1 intermediate and major veins export sucrose from the phloem parenchyma (PP) adjacent to the sieve element companion cell (SE/CC) complex, as in Arabidopsis. We surmise that abBS identity is subject to dorsoventral patterning and has components of PP identity. The observations provide first insights into the unique properties of abBS cells, cells previously considered to fulfill the same functions as other bundle sheath cells (BSCs), and a basis for understanding the C4 syndrome.
2021-03-02 | GSE157758 | GEO
Project description:Leaves of angiosperms are made up of multiple distinct cell types. While the function of mesophyll cells, guard cells, phloem companion cells and sieve elements are clearly described, this is not the case for the bundle sheath (BS). To provide insight into the role of the BS in the C3 species Arabidopsis thaliana, we labelled ribosomes in this cell type with a FLAG tag. We then used immunocapture to isolate these ribosomes followed by sequencing of resident mRNAs. This showed that 5% of genes showed specific splice forms in the BS, and that 15% of genes were preferentially expressed in these cells. The BS translatome strongly implicates the BS in specific roles in sulphur transport and metabolism, glucosinolate biosynthesis and trehalose metabolism. Much of the C4 cycle is differentially expressed between the C3 BS and the rest of the leaf. Furthermore, the global patterns of transcript residency on BS ribosomes overlap to a greater extent with cells of the root pericycle than any other cell type. This analysis provides the first insight into the molecular function of this cell type in C3 species, and also indicates that at least some of the characteristics of BS cells in C4 plants are likely ancestral traits unrelated to the C4 photosynthesis.
2014-02-02 | E-MTAB-4474 | biostudies-arrayexpress
Project description:A number of taxa utilize C4 photosynthesis, to limit the impact of photorespiration upon photosynthetic performance. In order to achieve a local elevation of CO2 concentration, maize plants possess two photosynthetic cell types. Rubisco accumulation is restricted to bundle sheath (BS) cells that surround the leaf veins. Carbon fixation occurs initially in adjacent mesophyll (ME) cells. C4 compounds are transported into the BS cells where they are subsequently decarboxylated, releasing CO2. Although the major components of the C4 pathway have been well characterized, less is known about further metabolic partitioning in the maize leaf. Microarray hybridizations have been performed in order to further investigate metabolic differences between BS and ME cell types. BS strands and ME protoplasts were isolated from the leaves of 10 day old maize seedlings by mechanical disruption and enzymatic digestion respectively. To control for differences arising from these different protocols, total leaf (TO) and total leaf stress (ST) samples were also isolated. The ST sample was subjected to the same treatments as the ME sample, with the omission of cell-wall degrading enzymes. Leaves for the TO sample were harvested as for the BS strand sample. An interwoven loop design was used to compare the four treatment groups. A biological group consisted of a growth of plants from which pooled individuals were taken for the four treatments. Six biological replicates (groups) were used. Labeling was performed using the Genisphere Array 900-MPX kit according to the manufacturer's protocol. Post hybridization washes were performed according to the recommendations of the Maize Oligo Array Project. Scan settings were used for detection of moderate to high expression signals (gain ~ 60%. power 90%). Following hybridization with TO cDNA, ~1/3 of features provided signal above twice background and below saturation. A number of taxa utilize C4 photosynthesis, to limit the impact of photorespiration upon photosynthetic performance. In order to achieve a local elevation of CO2 concentration, maize plants possess two photosynthetic cell types. Rubisco accumulation is restricted to bundle sheath (BS) cells that surround the leaf veins. Carbon fixation occurs initially in adjacent mesophyll (ME) cells. C4 compounds are transported into the BS cells where they are subsequently decarboxylated, releasing CO2. Although the major components of the C4 pathway have been well characterized, less is known about further metabolic partitioning in the maize leaf. Microarray hybridizations have been performed in order to further investigate metabolic differences between BS and ME cell types. BS strands and ME protoplasts were isolated from the leaves of 10 day old maize seedlings by mechanical disruption and enzymatic digestion respectively. To control for differences arising from these different protocols, total leaf (TO) and total leaf stress (ST) samples were also isolated. The ST sample was subjected to the same treatments as the ME sample, with the omission of cell-wall degrading enzymes. Leaves for the TO sample were harvested as for the BS strand sample. An interwoven loop design was used to compare the four treatment groups. A biological group consisted of a growth of plants from which pooled individuals were taken for the four treatments. Six biological replicates (groups) were used. Labeling was performed using the Genisphere Array 900-MPX kit according to the manufacturer's protocol. Post hybridization washes were performed according to the recommendations of the Maize Oligo Array Project. Scan settings were used for detection of moderate to high expression signals (gain ~ 60%. power 90%). Following hybridization with TO cDNA, ~1/3 of features provided signal above twice background and below saturation. Keywords: Gene expression profiling of bundle sheath and mesophyll cell types
2005-12-24 | GSE3890 | GEO
Project description:Band9 maize B73 leaf, Bundle sheath strand section1(0-1.5cm) biological replica1 SDS-PAGE trypsin Orbitrap
2011-04-15 | PRD000190 | Pride
Project description:The biotrophic fungus Ustilago maydis causes smut disease on maize (Zea mays L.), which is characterized by immense plant tumours. To establish disease and reprogram organ primordia to tumours, U. maydis deploys effector proteins in an organ-specific manner. However, the cellular contribution to leaf tumours remains unknown. We investigated leaf tumour formation on the tissue- and cell type-specific level. Cytology and metabolite analysis were deployed to understand the cellular basis for tumourigenesis. Laser-capture microdissection was performed to gain a cell-type specific transcriptome of U. maydis during tumour formation. In-vivo visualization of plant DNA synthesis identified bundle sheath cells as the origin of hyperplasic tumour cells, while mesophyll cells become hypertrophic tumour cells. Cell type specific transcriptome profiling of U. maydis revealed tailored expression of fungal effector genes. Moreover, U. maydis See1 was identified the first cell type specific fungal effector, being required for induction of cell cycle reactivation in bundle sheath cells. Identification of distinct cellular mechanisms in two different leave cell types, and See1 as an effector for induction of proliferation of bundle-sheath cells, are major steps in understanding U. maydis-induced tumor formation. Moreover, the cell-type specific U. maydis transcriptome data is a valuable resource to the scientific community.
2018-02-13 | GSE105770 | GEO