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Li Z, Tu M, Qin F, Shui G, Xu D, Zang X. Identification of Indicator Genes for Agar Accumulation in Gracilariopsis lemaneiformis (Rhodophyta). Int J Mol Sci 2024; 25:4606. [PMID: 38731824 PMCID: PMC11083068 DOI: 10.3390/ijms25094606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 04/17/2024] [Accepted: 04/18/2024] [Indexed: 05/13/2024] Open
Abstract
Agar, as a seaweed polysaccharide mainly extracted from Gracilariopsis lemaneiformis, has been commercially applied in multiple fields. To investigate factors indicating the agar accumulation in G. lemaneiformis, the agar content, soluble polysaccharides content, and expression level of 11 genes involved in the agar biosynthesis were analysed under 4 treatments, namely salinity, temperature, and nitrogen and phosphorus concentrations. The salinity exerted the greatest impact on the agar content. Both high (40‱) and low (10‱, 20‱) salinity promoted agar accumulation in G. lemaneiformis by 4.06%, 2.59%, and 3.00%, respectively. The content of agar as a colloidal polysaccharide was more stable than the soluble polysaccharide content under the treatments. No significant correlation was noted between the two polysaccharides, and between the change in the agar content and the relative growth rate of the algae. The expression of all 11 genes was affected by the 4 treatments. Furthermore, in the cultivar 981 with high agar content (21.30 ± 0.95%) compared to that (16.23 ± 1.59%) of the wild diploid, the transcriptional level of 9 genes related to agar biosynthesis was upregulated. Comprehensive analysis of the correlation between agar accumulation and transcriptional level of genes related to agar biosynthesis in different cultivation conditions and different species of G. lemaneiformis, the change in the relative expression level of glucose-6-phosphate isomerase II (gpiII), mannose-6-phosphate isomerase (mpi), mannose-1-phosphate guanylyltransferase (mpg), and galactosyltransferase II (gatII) genes was highly correlated with the relative agar accumulation. This study lays a basis for selecting high-yield agar strains, as well as for targeted breeding, by using gene editing tools in the future.
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Affiliation(s)
| | | | | | | | - Di Xu
- Key Laboratory of Marine Genetics and Breeding, Ministry of Education, Ocean University of China, Qingdao 266003, China; (Z.L.); (M.T.); (F.Q.); (G.S.)
| | - Xiaonan Zang
- Key Laboratory of Marine Genetics and Breeding, Ministry of Education, Ocean University of China, Qingdao 266003, China; (Z.L.); (M.T.); (F.Q.); (G.S.)
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Estrella-Maldonado H, González-Cruz C, Matilde-Hernández C, Adame-García J, Santamaría JM, Santillán-Mendoza R, Flores-de la Rosa FR. Insights into the Molecular Basis of Huanglongbing Tolerance in Persian Lime ( Citrus latifolia Tan.) through a Transcriptomic Approach. Int J Mol Sci 2023; 24:ijms24087497. [PMID: 37108662 PMCID: PMC10144405 DOI: 10.3390/ijms24087497] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/14/2023] [Accepted: 04/17/2023] [Indexed: 04/29/2023] Open
Abstract
Huanglongbing (HLB) is a vascular disease of Citrus caused by three species of the α-proteobacteria "Candidatus Liberibacter", with "Candidatus Liberibacter asiaticus" (CLas) being the most widespread and the one causing significant economic losses in citrus-producing regions worldwide. However, Persian lime (Citrus latifolia Tanaka) has shown tolerance to the disease. To understand the molecular mechanisms of this tolerance, transcriptomic analysis of HLB was performed using asymptomatic and symptomatic leaves. RNA-Seq analysis revealed 652 differentially expressed genes (DEGs) in response to CLas infection, of which 457 were upregulated and 195 were downregulated. KEGG analysis revealed that after CLas infection, some DEGs were present in the plant-pathogen interaction and in the starch and sucrose metabolism pathways. DEGs present in the plant-pathogen interaction pathway suggests that tolerance against HLB in Persian lime could be mediated, at least partly, by the ClRSP2 and ClHSP90 genes. Previous reports documented that RSP2 and HSP90 showed low expression in susceptible citrus genotypes. Regarding the starch and sucrose metabolism pathways, some genes were identified as being related to the imbalance of starch accumulation. On the other hand, eight biotic stress-related genes were selected for further RT-qPCR analysis to validate our results. RT-qPCR results confirmed that symptomatic HLB leaves had high relative expression levels of the ClPR1, ClNFP, ClDR27, and ClSRK genes, whereas the ClHSL1, ClRPP13, ClPDR1, and ClNAC genes were expressed at lower levels than those from HLB asymptomatic leaves. Taken together, the present transcriptomic analysis contributes to the understanding of the CLas-Persian lime interaction in its natural environment and may set the basis for developing strategies for the integrated management of this important Citrus disease through the identification of blanks for genetic improvement.
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Affiliation(s)
- Humberto Estrella-Maldonado
- Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (INIFAP), Campo Experimental Ixtacuaco, Km 4.5 Carretera Martínez de la Torre-Tlapacoyan, Cong. Javier Rojo Gómez, Tlapacoyan C.P. 93600, Veracruz, Mexico
| | - Carlos González-Cruz
- Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (INIFAP), Campo Experimental Ixtacuaco, Km 4.5 Carretera Martínez de la Torre-Tlapacoyan, Cong. Javier Rojo Gómez, Tlapacoyan C.P. 93600, Veracruz, Mexico
| | - Cristian Matilde-Hernández
- Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (INIFAP), Campo Experimental Ixtacuaco, Km 4.5 Carretera Martínez de la Torre-Tlapacoyan, Cong. Javier Rojo Gómez, Tlapacoyan C.P. 93600, Veracruz, Mexico
| | - Jacel Adame-García
- Tecnológico Nacional de México, Campus Úrsulo Galván, Km 4.5 Carretera Cd. Cardel-Chachalacas, Úrsulo Galván C.P. 91667, Veracruz, Mexico
| | - Jorge M Santamaría
- Centro de Investigación Científica de Yucatán A.C., Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida C.P. 97205, Yucatán, Mexico
| | - Ricardo Santillán-Mendoza
- Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (INIFAP), Campo Experimental Ixtacuaco, Km 4.5 Carretera Martínez de la Torre-Tlapacoyan, Cong. Javier Rojo Gómez, Tlapacoyan C.P. 93600, Veracruz, Mexico
| | - Felipe Roberto Flores-de la Rosa
- Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (INIFAP), Campo Experimental Ixtacuaco, Km 4.5 Carretera Martínez de la Torre-Tlapacoyan, Cong. Javier Rojo Gómez, Tlapacoyan C.P. 93600, Veracruz, Mexico
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3
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Panahi B, Frahadian M, Dums JT, Hejazi MA. Integration of Cross Species RNA-seq Meta-Analysis and Machine-Learning Models Identifies the Most Important Salt Stress-Responsive Pathways in Microalga Dunaliella. Front Genet 2019; 10:752. [PMID: 31555319 PMCID: PMC6727038 DOI: 10.3389/fgene.2019.00752] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Accepted: 07/17/2019] [Indexed: 01/12/2023] Open
Abstract
Photosynthetic microalgae are potentially yielding sources of different high-value secondary metabolites. Salinity is a complex stress that influences various metabolite-related pathways in microalgae. To obtain a clear view of the underlying metabolic pathways and resolve contradictory information concerning the transcriptional regulation of Dunaliella species in salt stress conditions, RNA-seq meta-analysis along with systems levels analysis was conducted. A p-value combination technique with Fisher method was used for cross species meta-analysis on the transcriptomes of two Dunaliella salina and Dunaliellatertiolecta species. The potential functional impacts of core meta-genes were surveyed based on gene ontology and network analysis. In the current study, the integration of supervised machine-learning algorithms with RNA-seq meta-analysis was performed. The analysis shows that the lipid and nitrogen metabolism, structural proteins of photosynthesis apparatus, chaperone-mediated autophagy, and ROS-related genes are the keys and core elements of the Dunaliella salt stress response system. Cross-talk between Ca2+ signal transduction, lipid accumulation, and ROS signaling network in salt stress conditions are also proposed. Our novel approach opens new avenues for better understanding of microalgae stress response mechanisms and for selection of candidate gene targets for metabolite production in microalgae.
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Affiliation(s)
- Bahman Panahi
- Department of Genomics, Branch for Northwest & West region, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research, Education and Extension Organization (AREEO), Tabriz, Iran
| | - Mohammad Frahadian
- Department of Animal Science, Faculty of Agriculture, University of Tabriz, Tabriz, Iran
| | - Jacob T Dums
- Department of Plant and Soil Sciences, University of Delaware, Newark, DE, USA
| | - Mohammad Amin Hejazi
- Department of Food Biotechnology, Branch for Northwest & West region, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research, Education and Extension Organization (AREEO), Tabriz, Iran
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Gong F, Wang J, Li J. Isolation and characterization of peroxiredoxin 1 gene of Dunaliella salina. Gene 2017; 635:39-45. [DOI: 10.1016/j.gene.2017.09.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 08/05/2017] [Accepted: 09/08/2017] [Indexed: 10/18/2022]
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Fang L, Qi S, Xu Z, Wang W, He J, Chen X, Liu J. De novo transcriptomic profiling of Dunaliella salina reveals concordant flows of glycerol metabolic pathways upon reciprocal salinity changes. ALGAL RES 2017. [DOI: 10.1016/j.algal.2017.01.017] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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RING box protein-1 gene involved in flagellar disassembly of Dunaliella salina. Folia Microbiol (Praha) 2016; 62:57-62. [PMID: 27655397 DOI: 10.1007/s12223-016-0472-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 09/12/2016] [Indexed: 10/21/2022]
Abstract
Ring box protein-1 (RBX1), also called Regulator of Cullins-1 (ROC1), is a key component of SCF (Skp-1, cullins, F-box proteins) E3 ubiquitin ligases, which regulate diverse cellular processes by targeting protein substrates for degradation. Although RBX1 plays an important role in ubiquitination machinery of both prokaryotes and eukaryotes, studies on the RBX1 have not been involved in the unicellular green alga Dunaliella salina. In this study, a full-length RBX1 cDNA fragment of 817 bp was cloned using rapid amplification of cDNA end (RACE) technique. The full-length sequence contained an open reading frame of 411 bp encoding 136 amino acids. The predicted protein had a molecular molar mass of 14.8 kDa and pI of 5.9 with a high degree of homology to RBX1 from Chlamydomonas reinhardtii (92 %). Recombinant RBX1 was expressed in Escherichia coli BL21 and was purified and characterized. The apparent molecular mass of the recombinant protein was approximately 17 kDa, and the optimal induction time and concentration were 3 h and 0.1 mmol/L IPTG, respectively. The predicted 3D structures of RBX1 proteins contained RING-H2 finger domain including "Cys59-X2-Cys62-X30-Cys93-X1-His95-X2-His98-X2-Cys101-X10-Cys112-X2-Cys115." The expression of RBX1 protein was increased by 132 % during flagellar disassembly and decreased by 76 % during flagellar assembly of D. salina. The expression of RBX1 mRNA had a similar tendency with the expression of RBX1 protein. The results indicated that RBX1 responded to flagellar disassembly of D. salina.
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The relationship of glycerol and glycolysis metabolism patway under hyperosmotic stress in Dunaliella salina. Open Life Sci 2014. [DOI: 10.2478/s11535-014-0323-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractThis study detected the upstream and downstream key genes of glycolysis in Dunaliella Salina by using Real-time Fluorescence Quantitative PCR assays and measurement of enzyme activity. The results were as follows: the levels of transcription, enzyme activity, and protein of D. salina PFK were up-regulated under hyperosmotic stress while D. salina ENO were down-regulated. At the same time we monitored the change of intracellular degradation of starch, the synthesis of glycerol and PEP concentration in Dunaliella Salina under hyperosmotic stress. We found that lower expression of DsENO reduced the concentration of intracellular PEP which promoted the degradation of starch, and decreased the flow of carbon into the tricarboxylic acid cycle which would favor the synthesis of glycerol.
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Lin H, Fang L, Low CS, Chow Y, Lee YK. Occurrence of glycerol uptake in Dunaliella tertiolecta under hyperosmotic stress. FEBS J 2013; 280:1064-72. [PMID: 23279806 DOI: 10.1111/febs.12100] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 12/06/2012] [Accepted: 12/12/2012] [Indexed: 11/29/2022]
Abstract
The unicellular halotolerant green alga species Dunaliella are able to proliferate in extremely varied salinities by synthesizing intracellular glycerol and adjusting the cell shape and volume. However, some marine Dunaliella species such as Dunaliella tertiolecta are not able to regulate cell volume as an immediate response to counter external osmotic shock. Here we report that a rapid shock-response mechanism is present in Dunaliella tertiolecta, involving uptake of exogenous glycerol in response to hyperosmotic shock without changing cell volume, and this glycerol uptake activity is associated with the Dunaliella tertiolecta glycerol uptake protein 1 (DtGUP1) gene, which belongs to the membrane-bound O-acyltransferase. The mutant DtGUP1-E, in which the DtGUP1 gene is silenced, displayed an inability to take up glycerol from the medium and showed cell death under hyperosmotic shock. To our knowledge, this is the first time a gene product has been reported in Dunaliella tertiolecta that is involved in glycerol uptake activity under hyperosmotic stress.
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Affiliation(s)
- Huixin Lin
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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Shi K, Li J, Han K, Jiang H, Xue L. The degradation of kinesin-like calmodulin binding protein of D. salina (DsKCBP) is mediated by the ubiquitin-proteasome system. Mol Biol Rep 2012; 40:3113-21. [PMID: 23271117 DOI: 10.1007/s11033-012-2385-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 12/17/2012] [Indexed: 12/16/2022]
Abstract
Kinesin-like calmodulin binding protein (KCBP) is a member of kinesin-14 subfamily with unconventional domains distinct from other kinesins. This unique kinesin has the myosin tail homology 4 domain (MyTH4) and band4.1, ezrin, radixin and moesin domain (FERM) at the N-terminal which interact with several cytoskeleton proteins. Although KCBP is implicated in several microtubule-related cellular processes, studies on the KCBP of Dunaliella salina (DsKCBP) have not been reported. In this study, the roles of DsKCBP in flagella and cytoskeleton were investigated and the results showed that DsKCBP was present in flagella and upregulated during flagellar assembly indicting that it may be a flagellar kinesin and plays a role in flagellar assembly. A MyTH4-FERM domain of the DsKCBP was identified as a microtubule and actin interacting site. The interaction of DsKCBP with both microtubules and actin microfilaments suggests that this kinesin may be employed to coordinate these two cytoskeleton elements in algal cells. To gain more insights into the cellular function of the kinesin, DsKCBP-interacting proteins were examined using yeast two-hybrid screen. A 26S proteasome subunit Rpn8 was identified as a novel interacting partner of DsKCBP and the MyTH4-FERM domain was necessary for the interaction of DsKCBP with Rpn8. Furthermore, the DsKCBP was polyubiquitinated and up-regulated by proteasome inhibitor and degraded by ubiquitin-proteasome system indicating that proteasome is related to kinesin degradation.
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Affiliation(s)
- Ke Shi
- Laboratory for Cell Biology, The First Affiliated Hospital, Zhengzhou University, 40 Daxue Road, Henan 450052, China
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Cloning and characterization of ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit (RbcS) cDNA from green microalga Ankistrodesmus convolutus. Mol Biol Rep 2011; 38:5297-305. [PMID: 21287365 DOI: 10.1007/s11033-011-0679-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Accepted: 01/10/2011] [Indexed: 10/18/2022]
Abstract
An initial study on gene cloning and characterization of unicellular green microalga Ankistrodesmus convolutus was carried out to isolate and characterize the full-length cDNA of ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit (RbcS) as a first step towards elucidating the structure of A. convolutus RbcS gene. The full-length of A. convolutus RbcS cDNA (AcRbcS) contained 28 bp of 5' untranslated region (UTR), 225 bp of 3' non-coding region, and an open reading frame of 165 amino acids consisting of a chloroplast transit peptide with 24 amino acids and a mature protein of 141 amino acids. The amino acid sequence has high identity to those of other green algae RbcS genes. The AcRbcS contained a few conserved domains including protein kinase C phosphorylation site, tyrosine kinase phosphorylation site and N-myristoylation sites. The AcRbcS was successfully expressed in Escherichia coli and a ~21 kDa of anticipated protein band was observed on SDS-PAGE. From the phylogenetic analysis of RbcS protein sequences, it was found that the RbcS of A. convolutus has closer genetic relationship with green microalgae species compared to those of green seaweed and green macroalgae species. Southern hybridization analysis revealed that the AcRbcS is a member of a small multigene family comprising of two to six members in A. convolutus genome. Under different illumination conditions, RT-PCR analysis showed that AcRbcS transcription was reduced in the dark, and drastically recovered in the light condition. Results presented in this paper established a good foundation for further study on the photosynthetic process of A. convolutus and other green algae species where little information is known on Rubisco small subunit.
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Song T, Gao Q, Xu Z, Song R. The cloning and characterization of two ammonium transporters in the salt-resistant green alga, Dunaliella viridis. Mol Biol Rep 2010; 38:4797-804. [PMID: 21153924 DOI: 10.1007/s11033-010-0621-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Accepted: 11/26/2010] [Indexed: 11/26/2022]
Abstract
Ammonium (NH(4) (+)) transport is a key process in nitrogen metabolism. To elucidate the role of ammonium transporters in the nitrogen consumption of the salt-resistant green alga, Dunaliella viridis, two ammonium transporter genes, DvAMT1;1 and DvAMT1;2, were isolated from cDNA libraries of D. viridis. DvAMT1;1 and DvAMT1;2 share only 40% amino acid identity, indicating that they have highly divergent coding sequences. Functional complementation in a yeast mutant defective in ammonium uptake indicated that both DvAMT1;1 and DvAMT1;2 were functional ammonium transporters. Quantitative RT-PCR showed similar expression patterns, but different transcript abundance levels, for DvAMT1;1 and DvAMT1;2 under different nitrogen conditions. Both were induced at low nitrogen and inhibited at high nitrogen concentrations, especially when NH(4) (+) was the nitrogen source. At the transcriptional level, DvAMT1;1 was diurnally regulated, while DvAMT1;2 was not. In addition, under NaCl concentrations that ranged from 0.5 to 3 M, DvAMT1;1 was down-regulated at the higher salt conditions; conversely, DvAMT1;2 maintained a relatively low, but stable, transcript abundance. The observed differences in transcriptional regulation of DvAMT1;1 and DvAMT1;2 are indicative of their diverse physiological functions in D. viridis.
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Affiliation(s)
- Ting Song
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
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Alkayal F, Albion RL, Tillett RL, Hathwaik LT, Lemos MS, Cushman JC. Expressed sequence tag (EST) profiling in hyper saline shocked Dunaliella salina reveals high expression of protein synthetic apparatus components. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2010; 179:437-49. [PMID: 21802602 DOI: 10.1016/j.plantsci.2010.07.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Revised: 06/28/2010] [Accepted: 07/01/2010] [Indexed: 05/10/2023]
Abstract
The unicellular, halotolerant, green alga, Dunaliella salina (Chlorophyceae) has the unique ability to adapt and grow in a wide range of salt conditions from about 0.05 to 5.5M. To better understand the molecular basis of its salinity tolerance, a complementary DNA (cDNA) library was constructed from D. salina cells adapted to 2.5M NaCl, salt-shocked at 3.4M NaCl for 5h, and used to generate an expressed sequence tag (EST) database. ESTs were obtained for 2831 clones representing 1401 unique transcripts. Putative functions were assigned to 1901 (67.2%) ESTs after comparison with protein databases. An additional 154 (5.4%) ESTs had significant similarity to known sequences whose functions are unclear and 776 (27.4%) had no similarity to known sequences. For those D. salina ESTs for which functional assignments could be made, the largest functional categories included protein synthesis (35.7%), energy (photosynthesis) (21.4%), primary metabolism (13.8%) and protein fate (6.8%). Within the protein synthesis category, the vast majority of ESTs (80.3%) encoded ribosomal proteins representing about 95% of the approximately 82 subunits of the cytosolic ribosome indicating that D. salina invests substantial resources in the production and maintenance of protein synthesis. The increased mRNA expression upon salinity shock was verified for a small set of selected genes by real-time, quantitative reverse-transcription-polymerase chain reaction (qRT-PCR). This EST collection also provided important new insights into the genetic underpinnings for the biosynthesis and utilization of glycerol and other osmoprotectants, the carotenoid biosynthetic pathway, reactive oxygen-scavenging enzymes, and molecular chaperones (heat shock proteins) not described previously for D. salina. EST discovery also revealed the existence of RNA interference and signaling pathways associated with osmotic stress adaptation. The unknown ESTs described here provide a rich resource for the identification of novel genes associated with the mechanistic basis of salinity stress tolerance and other stress-adaptive traits.
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Affiliation(s)
- Fadi Alkayal
- Dasman Center for Research and Treatment of Diabetes, P.O Box 1180, Dasman, Kuwait
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Troncoso-Ponce MA, Rivoal J, Cejudo FJ, Dorion S, Garcés R, Martínez-Force E. Cloning, biochemical characterisation, tissue localisation and possible post-translational regulatory mechanism of the cytosolic phosphoglucose isomerase from developing sunflower seeds. PLANTA 2010; 232:845-859. [PMID: 20628759 DOI: 10.1007/s00425-010-1219-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Accepted: 06/23/2010] [Indexed: 05/29/2023]
Abstract
Lipid biosynthesis in developing sunflower (Helianthus annuus L.) seeds requires reducing power. One of the main sources of cellular NADPH is the oxidative pentose phosphate pathway (OPPP), generated from the oxidation of glucose-6-phosphate. This glycolytic intermediate, which can be imported to the plastid and enter in the OPPP, is the substrate and product of cytosolic phosphoglucose isomerase (cPGI, EC 5.3.1.9). In this report, we describe the cloning of a full-length cDNA encoding cPGI from developing sunflower seeds. The sequence was predicted to code for a protein of 566 residues characterised by the presence of two sugar isomerase domains. This cDNA was heterologously expressed in Escherichia coli as a His-tagged protein. The recombinant protein was purified using immobilised metal ion affinity chromatography and biochemically characterised. The enzyme had a specific activity of 1,436 micromol min(-1) mg(-1) and 1,011 micromol min(-1) mg(-1) protein when the reaction was initiated with glucose-6-phosphate and fructose-6-phosphate, respectively. Activity was not affected by erythrose-4-phosphate, but was inhibited by 6-P gluconate and glyceraldehyde-3-phosphate. A polyclonal immune serum was raised against the purified enzyme, allowing the study of protein levels during the period of active lipid synthesis in seeds. These results were compared with PGI activity profiles and mRNA expression levels obtained from Q-PCR studies. Our results point to the existence of a possible post-translational regulatory mechanism during seed development. Immunolocalisation of the protein in seed tissues further indicated that cPGI is highly expressed in the procambial ring.
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