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Proteomic Analysis of Proteins Related to Defense Responses in Arabidopsis Plants Transformed with the rolB Oncogene. Int J Mol Sci 2023; 24:ijms24031880. [PMID: 36768198 PMCID: PMC9915171 DOI: 10.3390/ijms24031880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Revised: 01/10/2023] [Accepted: 01/16/2023] [Indexed: 01/20/2023] Open
Abstract
During Agrobacterium rhizogenes-plant interaction, the rolB gene is transferred into the plant genome and is stably inherited in the plant's offspring. Among the numerous effects of rolB on plant metabolism, including the activation of secondary metabolism, its effect on plant defense systems has not been sufficiently studied. In this work, we performed a proteomic analysis of rolB-expressing Arabidopsis thaliana plants with particular focus on defense proteins. We found a total of 77 overexpressed proteins and 64 underexpressed proteins in rolB-transformed plants using two-dimensional gel electrophoresis and MALDI mass spectrometry. In the rolB-transformed plants, we found a reduced amount of scaffold proteins RACK1A, RACK1B, and RACK1C, which are known as receptors for activated C-kinase 1. The proteomic analysis showed that rolB could suppress the plant immune system by suppressing the RNA-binding proteins GRP7, CP29B, and CP31B, which action are similar to the action of type-III bacterial effectors. At the same time, rolB plants induce the massive biosynthesis of protective proteins VSP1 and VSP2, as well as pathogenesis-related protein PR-4, which are markers of the activated jasmonate pathway. The increased contents of glutathione-S-transferases F6, F2, F10, U19, and DHAR1 and the osmotin-like defense protein OSM34 were found. The defense-associated protein PCaP1, which is required for oligogalacturonide-induced priming and immunity, was upregulated. Moreover, rolB-transformed plants showed the activation of all components of the PYK10 defense complex that is involved in the metabolism of glucosinolates. We hypothesized that various defense systems activated by rolB protect the host plant from competing phytopathogens and created an effective ecological niche for A. rhizogenes. A RolB → RACK1A signaling module was proposed that might exert most of the rolB-mediated effects on plant physiology. Our proteomics data are available via ProteomeXchange with identifier PXD037959.
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Shkryl Y, Yugay Y, Vasyutkina E, Chukhlomina E, Rusapetova T, Bulgakov V. The RolB/RolC homolog from sweet potato promotes early flowering and triggers premature leaf senescence in transgenic Arabidopsis thaliana plants. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2022; 193:50-60. [PMID: 36323197 DOI: 10.1016/j.plaphy.2022.10.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Revised: 09/30/2022] [Accepted: 10/17/2022] [Indexed: 06/16/2023]
Abstract
Expression of the root oncogenic loci (rol) genes from Agrobacterium rhizogenes provokes multiple divergent effects on physiological properties in transgenic plants and cell cultures. Recently, the homolog of the rolB and rolC oncogenes, named Ib-rolB/C, has been identified in the genome of a naturally transgenic food crop, i.e. sweet potato. In this study, we revealed that the Ipomoea batatas genome contains two full-length copies of Ib-rolB/C. The expression level of Ib-rolB/C in leaves of sweet potato showed a clear age-dependent pattern and increased as leaves senesce. Moreover, dark-induced senescence strongly up-regulates transcription of the Ib-rolB/C gene. Though Ib-rolB/C shares homology with its counterparts in A. rhizogenes, this gene was not capable to induce hairy roots or tumors in kalanchoe and tobacco plants. The Ib-rolB/C gene induced early-flowering phenotype, altered leaf morphology, and promoted premature leaf senescence in transgenic Arabidopsis thaliana plants. At the same time, Ib-rolB/C did not affect root morphology and biomass. Our results suggest that Ib-RolB/RolC participates in both age- and dark-triggered leaf senescence programs.
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Affiliation(s)
- Yury Shkryl
- Federal Scientific Center of the East Asia Terrestrial Biodiversity of the Far East Branch of Russian Academy of Sciences, Vladivostok, 690022, Russia.
| | - Yulia Yugay
- Federal Scientific Center of the East Asia Terrestrial Biodiversity of the Far East Branch of Russian Academy of Sciences, Vladivostok, 690022, Russia
| | - Elena Vasyutkina
- Federal Scientific Center of the East Asia Terrestrial Biodiversity of the Far East Branch of Russian Academy of Sciences, Vladivostok, 690022, Russia
| | - Ekaterina Chukhlomina
- Federal Scientific Center of the East Asia Terrestrial Biodiversity of the Far East Branch of Russian Academy of Sciences, Vladivostok, 690022, Russia
| | - Tatiana Rusapetova
- Federal Scientific Center of the East Asia Terrestrial Biodiversity of the Far East Branch of Russian Academy of Sciences, Vladivostok, 690022, Russia
| | - Victor Bulgakov
- Federal Scientific Center of the East Asia Terrestrial Biodiversity of the Far East Branch of Russian Academy of Sciences, Vladivostok, 690022, Russia
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Kaushal P, Dwivedi KK, Radhakrishna A, Srivastava MK, Kumar V, Roy AK, Malaviya DR. Partitioning Apomixis Components to Understand and Utilize Gametophytic Apomixis. FRONTIERS IN PLANT SCIENCE 2019; 10:256. [PMID: 30906306 PMCID: PMC6418048 DOI: 10.3389/fpls.2019.00256] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 02/18/2019] [Indexed: 05/07/2023]
Abstract
Apomixis is a method of reproduction to generate clonal seeds and offers tremendous potential to fix heterozygosity and hybrid vigor. The process of apomictic seed development is complex and comprises three distinct components, viz., apomeiosis (leading to formation of unreduced egg cell), parthenogenesis (development of embryo without fertilization) and functional endosperm development. Recently, in many crops, these three components are reported to be uncoupled leading to their partitioning. This review provides insight into the recent status of our understanding surrounding partitioning apomixis components in gametophytic apomictic plants and research avenues that it offers to help understand the biology of apomixis. Possible consequences leading to diversity in seed developmental pathways, resources to understand apomixis, inheritance and identification of candidate gene(s) for partitioned components, as well as contribution towards creation of variability are all discussed. The potential of Panicum maximum, an aposporous crop, is also discussed as a model crop to study partitioning principle and effects. Modifications in cytogenetic status, as well as endosperm imprinting effects arising due to partitioning effects, opens up new opportunities to understand and utilize apomixis components, especially towards synthesizing apomixis in crops.
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Affiliation(s)
- Pankaj Kaushal
- ICAR-National Institute of Biotic Stress Management, Raipur, India
| | | | | | | | - Vinay Kumar
- ICAR-National Institute of Biotic Stress Management, Raipur, India
| | - Ajoy Kumar Roy
- ICAR-Indian Grassland and Fodder Research Institute, Jhansi, India
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Abstract
This review by Figueiredo and Köhler describes the molecular mechanisms driving seed development. They review the role of the hormone auxin for the initial development of the three seed structures and as a trigger of fertilization-independent seed development. The evolution of seeds defines a remarkable landmark in the history of land plants. A developing seed contains three genetically distinct structures: the embryo, the nourishing tissue, and the seed coat. While fertilization is necessary to initiate seed development in most plant species, apomicts have evolved mechanisms allowing seed formation independently of fertilization. Despite their socio–economical relevance, the molecular mechanisms driving seed development have only recently begun to be understood. Here we review the current knowledge on the role of the hormone auxin for the initial development of the three seed structures and as a trigger of fertilization-independent seed development.
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Affiliation(s)
- Duarte D Figueiredo
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala SE-750 07, Sweden
| | - Claudia Köhler
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala SE-750 07, Sweden
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5
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Bulgakov VP, Vereshchagina YV, Bulgakov DV, Veremeichik GN, Shkryl YN. The rolB plant oncogene affects multiple signaling protein modules related to hormone signaling and plant defense. Sci Rep 2018; 8:2285. [PMID: 29396465 PMCID: PMC5797197 DOI: 10.1038/s41598-018-20694-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 01/23/2018] [Indexed: 01/11/2023] Open
Abstract
The rolB plant oncogene of Agrobacterium rhizogenes perturbs many biochemical processes in transformed plant cells, thereby causing their neoplastic reprogramming. The oncogene renders the cells more tolerant to environmental stresses and herbicides and inhibits ROS elevation and programmed cell death. In the present work, we performed a proteomic analysis of Arabidopsis thaliana rolB-expressing callus line AtB-2, which represents a line with moderate expression of the oncogene. Our results show that under these conditions rolB greatly perturbs the expression of some chaperone-type proteins such as heat-shock proteins and cyclophilins. Heat-shock proteins of the DnaK subfamily were overexpressed in rolB-transformed calli, whereas the abundance of cyclophilins, members of the closely related single-domain cyclophilin family was decreased. Real-time PCR analysis of corresponding genes confirmed the reliability of proteomics data because gene expression correlated well with the expression of proteins. Bioinformatics analysis indicates that rolB can potentially affect several levels of signaling protein modules, including effector-triggered immunity (via the RPM1-RPS2 signaling module), the miRNA processing machinery, auxin and cytokinin signaling, the calcium signaling system and secondary metabolism.
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Affiliation(s)
- Victor P Bulgakov
- Institute of Biology and Soil Science, Far Eastern Branch of the Russian Academy of Sciences, 159 Stoletija Str., Vladivostok, 690022, Russia. .,Far Eastern Federal University, Vladivostok, 690950, Russia.
| | - Yulia V Vereshchagina
- Institute of Biology and Soil Science, Far Eastern Branch of the Russian Academy of Sciences, 159 Stoletija Str., Vladivostok, 690022, Russia
| | - Dmitry V Bulgakov
- Institute of Biology and Soil Science, Far Eastern Branch of the Russian Academy of Sciences, 159 Stoletija Str., Vladivostok, 690022, Russia
| | - Galina N Veremeichik
- Institute of Biology and Soil Science, Far Eastern Branch of the Russian Academy of Sciences, 159 Stoletija Str., Vladivostok, 690022, Russia
| | - Yuri N Shkryl
- Institute of Biology and Soil Science, Far Eastern Branch of the Russian Academy of Sciences, 159 Stoletija Str., Vladivostok, 690022, Russia
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Abstract
The transfer of T-DNA sequences from Agrobacterium to plant cells is a well-understood process of natural genetic engineering. The expression of T-DNA genes in plants leads to tumors, hairy roots, or transgenic plants. The transformed cells multiply and synthesize small molecules, called opines, used by Agrobacteria for their growth. Several T-DNA genes stimulate or influence plant growth. Among these, iaaH and iaaM encode proteins involved in auxin synthesis, whereas ipt encodes a protein involved in cytokinin synthesis. Growth can also be induced or modified by other T-DNA genes, collectively called plast genes (for phenotypic plasticity). The plast genes are defined by their common ancestry and are mostly found on T-DNAs. They can influence plant growth in different ways, but the molecular basis of their morphogenetic activity remains largely unclear. Only some plast genes, such as 6b, rolB, rolC, and orf13, have been studied in detail. Plast genes have a significant potential for applied research and may be used to modify the growth of crop plants. In this review, I summarize the most important findings and models from 30 years of plast gene research and propose some outlooks for the future.
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Tang Q, Zang G, Cheng C, Luan M, Dai Z, Xu Y, Yang Z, Zhao L, Su J. Diplosporous development in Boehmeria tricuspis: Insights from de novo transcriptome assembly and comprehensive expression profiling. Sci Rep 2017; 7:46043. [PMID: 28382950 PMCID: PMC5382578 DOI: 10.1038/srep46043] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 03/07/2017] [Indexed: 01/05/2023] Open
Abstract
Boehmeria tricuspis includes sexually reproducing diploid and apomictic triploid individuals. Previously, we established that triploid B. tricuspis reproduces through obligate diplospory. To understand the molecular basis of apomictic development in B. tricuspis, we sequenced and compared transcriptomic profiles of the flowers of sexual and apomictic plants at four key developmental stages. A total of 283,341 unique transcripts were obtained from 1,463 million high-quality paired-end reads. In total, 18,899 unigenes were differentially expressed between the reproductive types at the four stages. By classifying the transcripts into gene ontology categories of differentially expressed genes, we showed that differential plant hormone signal transduction, cell cycle regulation, and transcription factor regulation are possibly involved in apomictic development and/or a polyploidization response in B. tricuspis. Furthermore, we suggest that specific gene families are possibly related to apomixis and might have important effects on diplosporous floral development. These results make a notable contribution to our understanding of the molecular basis of diplosporous development in B. tricuspis.
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Affiliation(s)
- Qing Tang
- Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, 348 West Xianjiahu Road, Changsha, Hunan, China
| | - Gonggu Zang
- Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, 348 West Xianjiahu Road, Changsha, Hunan, China
| | - Chaohua Cheng
- Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, 348 West Xianjiahu Road, Changsha, Hunan, China
| | - Mingbao Luan
- Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, 348 West Xianjiahu Road, Changsha, Hunan, China
| | - Zhigang Dai
- Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, 348 West Xianjiahu Road, Changsha, Hunan, China
| | - Ying Xu
- Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, 348 West Xianjiahu Road, Changsha, Hunan, China
| | - Zemao Yang
- Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, 348 West Xianjiahu Road, Changsha, Hunan, China
| | - Lining Zhao
- Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, 348 West Xianjiahu Road, Changsha, Hunan, China
| | - Jianguang Su
- Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, 348 West Xianjiahu Road, Changsha, Hunan, China
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8
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Chen K, Otten L. Natural Agrobacterium Transformants: Recent Results and Some Theoretical Considerations. FRONTIERS IN PLANT SCIENCE 2017; 8:1600. [PMID: 28966626 PMCID: PMC5606197 DOI: 10.3389/fpls.2017.01600] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 08/31/2017] [Indexed: 05/19/2023]
Abstract
Agrobacterium rhizogenes causes hairy root growth on a large number of plant species. It does so by transferring specific DNA fragments (T-DNA) from its root-inducing plasmid (pRi) into plant cells. Expression of T-DNA genes leads to abnormal root growth and production of specific metabolites (opines) which are taken up by the bacterium and used for its growth. Recent work has shown that several Nicotiana, Linaria, and Ipomoea species contain T-DNA genes from A. rhizogenes in their genomes. Plants carrying such T-DNAs (called cellular T-DNA or cT-DNA) can be considered as natural transformants. In the Nicotiana genus, seven different T-DNAs are found originating from different Agrobacterium strains, and in the Tomentosae section no <4 successive insertion events took place. In several cases cT-DNA genes were found to be expressed. In some Nicotiana tabacum cultivars the opine synthesis gene TB-mas2' is expressed in the roots. These cultivars were found to produce opines. Here we review what is known about natural Agrobacterium transformants, develop a theoretical framework to analyze this unusual phenomenon, and provide some outlines for further research.
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Affiliation(s)
- Ke Chen
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong UniversityShanghai, China
| | - Léon Otten
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique (CNRS)Strasbourg, France
- *Correspondence: Léon Otten
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9
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Kodahl N, Müller R, Lütken H. The Agrobacterium rhizogenes oncogenes rolB and ORF13 increase formation of generative shoots and induce dwarfism in Arabidopsis thaliana (L.) Heynh. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2016; 252:22-29. [PMID: 27717457 DOI: 10.1016/j.plantsci.2016.06.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 06/27/2016] [Accepted: 06/28/2016] [Indexed: 06/06/2023]
Abstract
Plant transformation with the wild type Ri plasmid T-DNA of Agrobacterium rhizogenes is a promising method for breeding of compact plants and has been the subject of numerous studies. However, knowledge concerning the isolated functions of single genes and ORFs from the plasmid is limited. The rolB and ORF13 oncogenes of A. rhizogenes show considerable promise in plant breeding, but have not been comprehensively studied. Detailed information regarding the morphological impact of specific genes of the Ri plasmid will allow for optimized targeted breeding of plants transformed with the wild type Ri plasmid T-DNA. rolB and ORF13 were recombined into the genome of Arabidopsis thaliana using Gateway® cloning and the effect on plant growth was assessed biometrically throughout the plants' life cycle. rolB-lines exhibited dwarfing, early necrosis of rosette leaves, altered leaf and flower morphology, and developed an increased number of inflorescences per rosette area compared to the wild type. ORF13-lines were extremely dwarfed, attaining only ca. 1% of the rosette area of the wild type, leaf and flower size was reduced, and the shape modified. The study documents that the traits inferred by the rolB oncogene yield plants with increased formation of generative shoots, but also result in some degree of premature senescence of vegetative organs. The extreme dwarfism seen in ORF13-lines indicate that this oncogene may be more important in the dwarfing response of plants transformed with the wild type Ri plasmid T-DNA than previously assumed and that transformation with this oncogene induces a very compact phenotype.
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Affiliation(s)
- Nete Kodahl
- Department of Plant and Environmental Sciences, University of Copenhagen, Højbakkegård Allé 9-13, DK-2630 Taastrup, Denmark.
| | - Renate Müller
- Department of Plant and Environmental Sciences, University of Copenhagen, Højbakkegård Allé 9-13, DK-2630 Taastrup, Denmark.
| | - Henrik Lütken
- Department of Plant and Environmental Sciences, University of Copenhagen, Højbakkegård Allé 9-13, DK-2630 Taastrup, Denmark.
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10
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Bettini PP, Marvasi M, Fani F, Lazzara L, Cosi E, Melani L, Mauro ML. Agrobacterium rhizogenes rolB gene affects photosynthesis and chlorophyll content in transgenic tomato (Solanum lycopersicum L.) plants. JOURNAL OF PLANT PHYSIOLOGY 2016; 204:27-35. [PMID: 27497742 DOI: 10.1016/j.jplph.2016.07.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 07/15/2016] [Accepted: 07/18/2016] [Indexed: 06/06/2023]
Abstract
Insertion of Agrobacterium rhizogenes rolB gene into plant genome affects plant development, hormone balance and defence. However, beside the current research, the overall transcriptional response and gene expression of rolB as a modulator in plant is unknown. Transformed rolB tomato plant (Solanum lycopersicum L.) cultivar Tondino has been used to investigate the differential expression profile. Tomato is a well-known model organism both at the genetic and molecular level, and one of the most important commercial food crops in the world. Through the construction and characterization of a cDNA subtracted library, we have investigated the differential gene expression between transgenic clones of rolB and control tomato and have evaluated genes specifically transcribed in transgenic rolB plants. Among the selected genes, five genes encoding for chlorophyll a/b binding protein, carbonic anhydrase, cytochrome b6/f complex Fe-S subunit, potassium efflux antiporter 3, and chloroplast small heat-shock protein, all involved in chloroplast function, were identified. Measurement of photosynthesis efficiency by the level of three different photosynthetic parameters (Fv/Fm, rETR, NPQ) showed rolB significant increase in non-photochemical quenching and a, b chlorophyll content. Our results point to highlight the role of rolB on plant fitness by improving photosynthesis.
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Affiliation(s)
- Priscilla P Bettini
- Dipartimento di Biologia, Università degli Studi di Firenze, via Madonna del Piano 6, 50019, Sesto Fiorentino (FI), Italy.
| | - Massimiliano Marvasi
- Dipartimento di Biologia, Università degli Studi di Firenze, via Madonna del Piano 6, 50019, Sesto Fiorentino (FI), Italy.
| | - Fabiola Fani
- Dipartimento di Biologia, Università degli Studi di Firenze, via Madonna del Piano 6, 50019, Sesto Fiorentino (FI), Italy.
| | - Luigi Lazzara
- Dipartimento di Biologia, Università degli Studi di Firenze, via Madonna del Piano 6, 50019, Sesto Fiorentino (FI), Italy.
| | - Elena Cosi
- Dipartimento di Biologia, Università degli Studi di Firenze, via Madonna del Piano 6, 50019, Sesto Fiorentino (FI), Italy.
| | - Lorenzo Melani
- Dipartimento di Biologia, Università degli Studi di Firenze, via Madonna del Piano 6, 50019, Sesto Fiorentino (FI), Italy.
| | - Maria Luisa Mauro
- Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, P.le A. Moro 5, 00185 Roma, Italy.
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Lioshina LG, Bulko OV. Plant regeneration from hairy roots and calluses of periwinkle Vinca minor L. and foxglove purple Digitalis purpurea L. CYTOL GENET+ 2014. [DOI: 10.3103/s009545271405003x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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12
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13
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Okada T, Hu Y, Tucker MR, Taylor JM, Johnson SD, Spriggs A, Tsuchiya T, Oelkers K, Rodrigues JC, Koltunow AM. Enlarging cells initiating apomixis in Hieracium praealtum transition to an embryo sac program prior to entering mitosis. PLANT PHYSIOLOGY 2013; 163:216-31. [PMID: 23864557 PMCID: PMC3762643 DOI: 10.1104/pp.113.219485] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 07/08/2013] [Indexed: 05/19/2023]
Abstract
Hieracium praealtum forms seeds asexually by apomixis. During ovule development, sexual reproduction initiates with megaspore mother cell entry into meiosis and formation of a tetrad of haploid megaspores. The sexual pathway ceases when a diploid aposporous initial (AI) cell differentiates, enlarges, and undergoes mitosis, forming an aposporous embryo sac that displaces sexual structures. Embryo and endosperm development in aposporous embryo sacs is fertilization independent. Transcriptional data relating to apomixis initiation in Hieracium spp. ovules is scarce and the functional identity of the AI cell relative to other ovule cell types is unclear. Enlarging AI cells with undivided nuclei, early aposporous embryo sacs containing two to four nuclei, and random groups of sporophytic ovule cells not undergoing these events were collected by laser capture microdissection. Isolated amplified messenger RNA samples were sequenced using the 454 pyrosequencing platform and comparatively analyzed to establish indicative roles of the captured cell types. Transcriptome and protein motif analyses showed that approximately one-half of the assembled contigs identified homologous sequences in Arabidopsis (Arabidopsis thaliana), of which the vast majority were expressed during early Arabidopsis ovule development. The sporophytic ovule cells were enriched in signaling functions. Gene expression indicative of meiosis was notably absent in enlarging AI cells, consistent with subsequent aposporous embryo sac formation without meiosis. The AI cell transcriptome was most similar to the early aposporous embryo sac transcriptome when comparing known functional annotations and both shared expressed genes involved in gametophyte development, suggesting that the enlarging AI cell is already transitioning to an embryo sac program prior to mitotic division.
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14
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Galla G, Volpato M, Sharbel TF, Barcaccia G. Computational identification of conserved microRNAs and their putative targets in the Hypericum perforatum L. flower transcriptome. PLANT REPRODUCTION 2013; 26:209-29. [PMID: 23846415 DOI: 10.1007/s00497-013-0227-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Accepted: 06/28/2013] [Indexed: 05/03/2023]
Abstract
MicroRNAs (miRNAs) have recently emerged as important regulators of gene expression in plants. Many miRNA families and their targets have been extensively studied in model species and major crops. We have characterized mature miRNAs along with their precursors and potential targets in Hypericum to generate a comprehensive list of conserved miRNA families and to investigate the regulatory role of selected miRNAs in biological processes that occur in the flower. St. John's wort (Hypericum perforatum L., 2n = 4x = 32), a medicinal plant that produces pharmaceutically important metabolites with therapeutic activities, was chosen because it is regarded as an attractive model system for the study of apomixis. A computational in silico prediction of structure, in combination with an in vitro validation, allowed us to identify 7 pre-miRNAs, including miR156, miR166, miR390, miR394, miR396, and miR414. We demonstrated that H. perforatum flowers share highly conserved miRNAs and that these miRNAs potentially target dozens of genes with a wide range of molecular functions, including metabolism, response to stress, flower development, and plant reproduction. Our analysis paves the way toward identifying flower-specific miRNAs that may differentiate the sexual and apomictic reproductive pathways.
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Affiliation(s)
- Giulio Galla
- Laboratory of Genetics and Genomics, DAFNAE, University of Padova, Campus of Agripolis, Viale dell'Università 16, 35020, Legnaro, Italy
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15
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Musiał K, Płachno BJ, Świątek P, Marciniuk J. Anatomy of ovary and ovule in dandelions (Taraxacum, Asteraceae). PROTOPLASMA 2013; 250:715-22. [PMID: 23001751 PMCID: PMC3659273 DOI: 10.1007/s00709-012-0455-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 09/11/2012] [Indexed: 05/10/2023]
Abstract
The genus Taraxacum Wigg. (Asteraceae) forms a polyploid complex within which there are strong links between the ploidy level and the mode of reproduction. Diploids are obligate sexual, whereas polyploids are usually apomictic. The paper reports on a comparative study of the ovary and especially the ovule anatomy in the diploid dandelion T. linearisquameum and the triploid T. gentile. Observations with light and electron microscopy revealed no essential differences in the anatomy of both the ovary and ovule in the examined species. Dandelion ovules are anatropous, unitegmic and tenuinucellate. In both sexual and apomictic species, a zonal differentiation of the integument is characteristic of the ovule. In the integumentary layers situated next to the endothelium, the cell walls are extremely thick and PAS positive. Data obtained from TEM indicate that these special walls have an open spongy structure and their cytoplasm shows evidence of gradual degeneration. Increased deposition of wall material in the integumentary cells surrounding the endothelium takes place especially around the chalazal pole of the embryo sac as well as around the central cell. In contrast, the integumentary cells surrounding the micropylar region have thin walls and exhibit a high metabolic activity. The role of the thick-walled integumentary layers in the dandelion ovule is discussed. We also consider whether this may be a feature of taxonomic importance.
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Affiliation(s)
- K Musiał
- Department of Plant Cytology and Embryology, Jagiellonian University, Grodzka 52, 31-044, Krakow, Poland.
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Tucker MR, Okada T, Johnson SD, Takaiwa F, Koltunow AMG. Sporophytic ovule tissues modulate the initiation and progression of apomixis in Hieracium. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:3229-41. [PMID: 22378948 PMCID: PMC3350933 DOI: 10.1093/jxb/ers047] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 01/30/2012] [Accepted: 01/31/2012] [Indexed: 05/21/2023]
Abstract
Apomixis in Hieracium subgenus Pilosella initiates in ovules when sporophytic cells termed aposporous initial (AI) cells enlarge near sexual cells undergoing meiosis. AI cells displace the sexual structures and divide by mitosis to form unreduced embryo sac(s) without meiosis (apomeiosis) that initiate fertilization-independent embryo and endosperm development. In some Hieracium subgenus Pilosella species, these events are controlled by the dominant LOSS OF APOMEIOSIS (LOA) and LOSS OF PARTHENOGENESIS (LOP) loci. In H. praealtum and H. piloselloides, which both contain the same core LOA locus, the timing and frequency of AI cell formation is altered in derived mutants exhibiting abnormal funiculus growth and in transgenic plants expressing rolB which alters cellular sensitivity to auxin. The impact on apomictic and sexual reproduction was examined here when a chimeric RNAse gene was targeted to the funiculus and basal portions of the ovule, and also when polar auxin transport was inhibited during ovule development following N-1-naphthylphthalamic acid (NPA) application. Both treatments led to ovule deformity in the funiculus and distal parts of the ovule and LOA-dependent alterations in the timing, position, and frequency of AI cell formation. In the case of NPA treatment, this correlated with increased expression of DR5:GFP in the ovule, which marks the accumulation of the plant hormone auxin. Our results show that sporophytic information potentiated by funiculus growth and polar auxin transport influences ovule development, the initiation of apomixis, and the progression of embryo sac development in Hieracium. Signals associated with ovule pattern formation and auxin distribution or perception may influence the capacity of sporophytic ovule cells to respond to LOA.
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Affiliation(s)
- Matthew R. Tucker
- CSIRO Plant Industry, Waite Campus, Hartley Grove, Urrbrae SA 5064, Australia
| | - Takashi Okada
- CSIRO Plant Industry, Waite Campus, Hartley Grove, Urrbrae SA 5064, Australia
| | - Susan D. Johnson
- CSIRO Plant Industry, Waite Campus, Hartley Grove, Urrbrae SA 5064, Australia
| | - Fumio Takaiwa
- Transgenic Crop Research and Development Centre, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan
| | - Anna M. G. Koltunow
- CSIRO Plant Industry, Waite Campus, Hartley Grove, Urrbrae SA 5064, Australia
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Bulgakov VP, Gorpenchenko TY, Veremeichik GN, Shkryl YN, Tchernoded GK, Bulgakov DV, Aminin DL, Zhuravlev YN. The rolB gene suppresses reactive oxygen species in transformed plant cells through the sustained activation of antioxidant defense. PLANT PHYSIOLOGY 2012; 158:1371-81. [PMID: 22271748 PMCID: PMC3291252 DOI: 10.1104/pp.111.191494] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Accepted: 01/20/2012] [Indexed: 05/05/2023]
Abstract
The rolB (for rooting locus of Agrobacterium rhizogenes) oncogene has previously been identified as a key player in the formation of hairy roots during the plant-A. rhizogenes interaction. In this study, using single-cell assays based on confocal microscopy, we demonstrated reduced levels of reactive oxygen species (ROS) in rolB-expressing Rubia cordifolia, Panax ginseng, and Arabidopsis (Arabidopsis thaliana) cells. The expression of rolB was sufficient to inhibit excessive elevations of ROS induced by paraquat, menadione, and light stress and prevent cell death induced by chronic oxidative stress. In rolB-expressing cells, we detected the enhanced expression of antioxidant genes encoding cytosolic ascorbate peroxidase, catalase, and superoxide dismutase. We conclude that, similar to pathogenic determinants in other pathogenic bacteria, rolB suppresses ROS and plays a role not only in cell differentiation but also in ROS metabolism.
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Affiliation(s)
- Victor P Bulgakov
- Institute of Biology and Soil Science, Far East Branch of Russian Academy of Sciences, Vladivostok 690022, Russia.
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18
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Cloning plants by seeds: Inheritance models and candidate genes to increase fundamental knowledge for engineering apomixis in sexual crops. J Biotechnol 2011; 159:291-311. [PMID: 21906637 DOI: 10.1016/j.jbiotec.2011.08.028] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2011] [Revised: 08/16/2011] [Accepted: 08/17/2011] [Indexed: 01/02/2023]
Abstract
Apomixis is desirable in agriculture as a reproductive strategy for cloning plants by seeds. Because embryos derive from the parthenogenic development of apomeiotic egg cells, apomixis excludes fertilization in addition to meiotic segregation and recombination, resulting in offspring that are exact replicas of the parent. Introgression of apomixis from wild relatives to crop species and transformation of sexual genotypes into apomictically reproducing ones are long-held goals of plant breeding. In fact, it is generally accepted that the introduction of apomixis into agronomically important crops will have revolutionary implications for agriculture. This review deals with the current genetic and molecular findings that have been collected from model species to elucidate the mechanisms of apomeiosis, parthenogenesis and apomixis as a whole. Our goal is to critically determine whether biotechnology can combine key genes known to control the expression of the processes miming the main components of apomixis in plants. Two natural apomicts, as the eudicot Hypericum perforatum L. (St. John's wort) and the monocot Paspalum spp. (crowngrass), and the sexual model species Arabidopsis thaliana are ideally suited for such investigations at the genomic and biotechnological levels. Some novel views and original concepts have been faced on this review, including (i) the parallel between Y-chromosome and apomixis-bearing chromosome (e.g., comparative genomic analyses revealed common features as repression of recombination events, accumulation of transposable elements and degeneration of genes) from the most primitive (Hypericum-type) to the most advanced (Paspalum-type) in evolutionary terms, and (ii) the link between apomixis and gene-specific silencing mechanisms (i.e., likely based on chromatin remodelling factors), with merging lines of evidence regarding the role of auxin in cell fate specification of embryo sac and egg cell development in Arabidopsis. The production of engineered plants exhibiting apomictic-like phenotypes is critically reviewed and discussed.
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Koltunow AMG, Johnson SD, Rodrigues JCM, Okada T, Hu Y, Tsuchiya T, Wilson S, Fletcher P, Ito K, Suzuki G, Mukai Y, Fehrer J, Bicknell RA. Sexual reproduction is the default mode in apomictic Hieracium subgenus Pilosella, in which two dominant loci function to enable apomixis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2011; 66:890-902. [PMID: 21418351 DOI: 10.1111/j.1365-313x.2011.04556.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Asexual seed formation, or apomixis, in the Hieracium subgenus Pilosella is controlled by two dominant independent genetic loci, LOSS OF APOMEIOSIS (LOA) and LOSS OF PARTHENOGENESIS (LOP). We examined apomixis mutants that had lost function in one or both loci to establish their developmental roles during seed formation. In apomicts, sexual reproduction is initiated first. Somatic aposporous initial (AI) cells differentiate near meiotic cells, and the sexual pathway is terminated as AI cells undergo mitotic embryo sac formation. Seed initiation is fertilization-independent. Using a partially penetrant cytotoxic reporter to inhibit meioisis, we showed that developmental events leading to the completion of meiotic tetrad formation are required for AI cell formation. Sexual initiation may therefore stimulate activity of the LOA locus, which was found to be required for AI cell formation and subsequent suppression of the sexual pathway. AI cells undergo nuclear division to form embryo sacs, in which LOP functions gametophytically to stimulate fertilization-independent embryo and endosperm formation. Loss of function in either locus results in partial reversion to sexual reproduction, and loss of function in both loci results in total reversion to sexual reproduction. Therefore, in these apomicts, sexual reproduction is the default reproductive mode upon which apomixis is superimposed. These loci are unlikely to encode genes essential for sexual reproduction, but may function to recruit the sexual machinery at specific time points to enable apomixis.
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Affiliation(s)
- Anna M G Koltunow
- Commonwealth Scientific and Industrial Research Organization Plant Industry, Glen Osmond, South Australia 5064, Australia.
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20
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Polegri L, Calderini O, Arcioni S, Pupilli F. Specific expression of apomixis-linked alleles revealed by comparative transcriptomic analysis of sexual and apomictic Paspalum simplex Morong flowers. JOURNAL OF EXPERIMENTAL BOTANY 2010; 61:1869-83. [PMID: 20231327 DOI: 10.1093/jxb/erq054] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Apomixis is defined as clonal reproduction by seed. A comparative transcriptomic analysis was undertaken between apomictic and sexual genotypes of Paspalum simplex Morong to identify apomixis-related polymorphisms at the level of mRNA. cDNA-AFLP (amplified fragment length polymorphism) profiling of apomictic and sexual flowers at several stages of development yielded 202 amplicons that showed several kinds of expression specificities. Among these, the large majority consisted of amplicons that were present only in specific stages of development of the apomictic flowers. Ten percent of polymorphic amplicons were present with almost identical intensity in all stages of the apomictic flowers and never in the sexual flowers. Reverse transcription-PCR (RT-PCR) and Southern analyses of these amplicons showed that they belong to constitutively expressed alleles that are specifically present on the apomixis-controlling locus of P. simplex. The most frequent biological functions inferred from the sequence homology of the apomixis-linked alleles were related to signal transduction and nucleic acid/protein-binding activities. Most of these apomixis-linked alleles showed nonsense and frameshift mutations, revealing their probable pseudogene nature. None of the amplicons that were present only in specific stages of development of the apomictic flowers co-segregated with apomixis, indicating they did not originate from additional apomictic alleles but more probably from differential regulation of the same allele in apomictic and sexual flowers. The molecular functions inferred from sequence analysis of these latter amplicons were related to seed storage protein and regulatory genes of various types. The results are discussed regarding the possible role in apomictic reproduction of the differentially expressed genes in relation to their specificity of expression and inferred molecular functions.
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Affiliation(s)
- Livia Polegri
- CNR-Institute for Plant Genetics, Research Division: Perugia, Via della Madonna alta 130, I-06128 Perugia, Italy
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21
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Yamada-Akiyama H, Akiyama Y, Ebina M, Xu Q, Tsuruta SI, Yazaki J, Kishimoto N, Kikuchi S, Takahara M, Takamizo T, Sugita SI, Nakagawa H. Analysis of expressed sequence tags in apomictic guineagrass (Panicum maximum). JOURNAL OF PLANT PHYSIOLOGY 2009; 166:750-61. [PMID: 19046615 DOI: 10.1016/j.jplph.2008.10.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2008] [Revised: 10/06/2008] [Accepted: 10/06/2008] [Indexed: 05/20/2023]
Abstract
Apomixis is an intriguing asexual mode of reproduction, because it produces maternal clones that permit vegetative reproduction through seeds. Guineagrass (Panicum maximum) has both facultative aposporous apomixis and obligate sexual modes of reproduction. Despite the importance of apomixis in guineagrass, expressed sequence tags (ESTs) for this condition have not been studied in this species. We constructed a guineagrass cDNA library from two aposporous strains, Ku5954 and GM64-3A, and utilized them as microarray probes. To find genes uniquely expressed in the immature pistils of apomicts, we performed a microarray analysis using target RNA from another apomict, OKI64. Of the 4608 probes in the microarray, only 394 showed clear gene expression in the immature pistils. Of the 394 expressed probes, 196 were successfully sequenced. Of these, 181 had significant homology with other species, including 10 ESTs with matches in a pistil cDNA library from another aposporous species, Cenchrus ciliaris. Of the remaining ESTs, three showed significant homology only with animal database sequences and the other 12 ESTs showed no homology with any previously registered sequence. In reverse-transcriptase PCR and real-time quantitative PCR, nine ESTs reliably detected ovary-specific gene expression. Of these, three revealed aposporous ovary-specific genes expressed in the early developmental stage, suggesting that these could be apomixis-related genes.
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Affiliation(s)
- Hitomi Yamada-Akiyama
- National Institute of Livestock and Grassland Science, Nasushiobara, Tochigi 329-2793, Japan
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22
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Rodrigues JCM, Tucker MR, Johnson SD, Hrmova M, Koltunow AMG. Sexual and apomictic seed formation in Hieracium requires the plant polycomb-group gene FERTILIZATION INDEPENDENT ENDOSPERM. THE PLANT CELL 2008; 20:2372-86. [PMID: 18812497 PMCID: PMC2570734 DOI: 10.1105/tpc.108.059287] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2008] [Revised: 09/02/2008] [Accepted: 09/10/2008] [Indexed: 05/21/2023]
Abstract
A Polycomb-Group (PcG) complex, FERTILIZATION INDEPENDENT SEED (FIS), represses endosperm development in Arabidopsis thaliana until fertilization occurs. The Hieracium genus contains apomictic species that form viable seeds asexually. To investigate FIS function during apomictic seed formation, FERTILIZATION INDEPENDENT ENDOSPERM (FIE), encoding a WD-repeat member of the FIS complex, was isolated and downregulated in sexual and apomictic Hieracium species. General downregulation led to defects in leaf and seed development, consistent with a role in developmental transitions and cell fate. PcG-like activity of Hieracium FIE was also supported by its interaction in vitro with the Arabidopsis CURLY LEAF PcG protein. By contrast, specific downregulation of FIE in developing seeds of sexual Hieracium did not result in autonomous endosperm proliferation but led to seed abortion after cross-pollination. Furthermore, in apomictic Hieracium, specific FIE downregulation inhibited autonomous embryo and endosperm initiation, and most autonomous seeds displayed defective embryo and endosperm growth. Therefore, FIE is required for both apomictic and fertilization-induced seed initiation in Hieracium. Since Hieracium FIE failed to interact with FIS class proteins in vitro, its partner proteins might differ from those in the FIS complex of Arabidopsis. These differences in protein interaction were attributed to structural modifications predicted from comparisons of Arabidopsis and Hieracium FIE molecular models.
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Affiliation(s)
- Julio C M Rodrigues
- Commonwealth Scientific and Industrial Research Organization Plant Industry, Glen Osmond, South Australia 5064, Australia
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23
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Tiwari RK, Trivedi M, Guang ZC, Guo GQ, Zheng GC. Genetic transformation of Gentiana macrophylla with Agrobacterium rhizogenes: growth and production of secoiridoid glucoside gentiopicroside in transformed hairy root cultures. PLANT CELL REPORTS 2007; 26:199-210. [PMID: 16972092 DOI: 10.1007/s00299-006-0236-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2005] [Revised: 05/19/2006] [Accepted: 08/18/2006] [Indexed: 05/11/2023]
Abstract
Hairy root cultures of Gentiana macrophylla were established by infecting the different explants four Agrobacterium rhizogenes strains namely A(4)GUS, R1000, LBA 9402 and ATCC11325, and hairy root lines were established with A. rhizogenes strain R1000 in 1/2 MS + B(5) medium. Initially, 42 independent hairy root clones were maintained and seven clones belongs to different category were evaluated for growth, morphology, integration and expression of Ri T-DNA genes, and alkaloid contents in dry root samples. On the basis of total root elongation, lateral root density and biomass accumulation on solid media, hairy root clones were separated into three categories. PCR and Southern hybridization analysis revealed both left and right T-DNA integration in the root clones and RT-PCR analysis confirmed the expression of hairy root inducible gene. GUS assay was also performed to confirm the integration of left T-DNA. The accumulation of considerable amounts of the root-specific secoiridoid glucosides gentiopicroside was observed in GM1 (T +/L and T +/R) and the GM2 (T +/L and T -/R DNA) type clones in considerably higher amount whether as two T -/L but T +/R callus-type clones (GM3) accumulated much less or only very negligible amounts of gentiopicroside. Out of four media composition the 1/2 MS + B(5) vitamin media was found most suitable. We found that initial establishment of root cultures largely depends on root:media ratio. Maximum growth rate was recorded in 1:50 root:media ratio. The maximum biomass in terms of fresh weight (33-fold) was achieved in 1/2 MS + B(5) media composition after 35 days in comparison to sixfold increase in control. The biomass increase was most abundant maximum from 15 to 30 days. Influence of A. rhizogenes strains and Ri plasmid of hairy root induction, the possible role of the T(L)-DNA and T(R)-DNA genes on growth pattern of hairy root, initial root inoculum:media ratio and effect of media composition is discussed.
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Affiliation(s)
- Rajesh Kumar Tiwari
- Institute of Cell Biology, School of Life Sciences, Lanzhou University, Lanzhou, 73000, Gansu, PR China.
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24
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Cecchetti V, Altamura MM, Serino G, Pomponi M, Falasca G, Costantino P, Cardarelli M. ROX1, a gene induced by rolB, is involved in procambial cell proliferation and xylem differentiation in tobacco stamen. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2007; 49:27-37. [PMID: 17233794 DOI: 10.1111/j.1365-313x.2006.02934.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The Agrobacterium rhizogenes oncogene rolB mimics the effects of auxin in that it increases the sensitivity of transformed cells to this hormone. Here we isolated a tobacco gene, ROX1, acting downstream of rolB. We show that plants with reduced levels of ROX1 mRNA, due to the expression of a 35S-driven ROX1-antisense construct, have flowers with stamens and pistils longer than normal because of an increased number of cells. Localized expression of rolB in anthers results in overexpression of ROX1 and reduced growth of stamens, due to a reduced number of cells. In addition, the longer stamens of antisense plants show a delayed xylem differentiation in the lateral bundles, primarily of the junction region between anther and filament, while the shorter stamens of ROX1-overexpressing plants show a precocious differentiation of xylem cells in the same tissues. Expression of ROX1 in stamens peaks at early stages of stamen growth, and ROX1 mRNA is localized mostly in anther procambial cells. The sequence of ROX1 shares a conserved element with a number of plant genes, including TED3, which is involved in xylem differentiation. These results point to a role of ROX1 in the balance between proliferation of procambial cells and xylem differentiation during stamen development.
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Affiliation(s)
- Valentina Cecchetti
- Dipartimento di Genetica e Biologia Molecolare, Universita La Sapienza, Piazzale Aldo Moro 5, 00185 Rome, Italy
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25
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Bulgakov VP, Kiselev KV, Yakovlev KV, Zhuravlev YN, Gontcharov AA, Odintsova NA. Agrobacterium-mediated transformation of sea urchin embryos. Biotechnol J 2006; 1:454-61. [PMID: 16892273 DOI: 10.1002/biot.200500045] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Agrobacterium-mediated transformation of higher plants is a well-known and powerful tool for transgene delivery to plant cells. In the present work, we studied whether Agrobacterium can transfer genetic information to animal (sea urchin) embryos. Sea urchin embryos were co-cultivated with A. tumefaciens strains carrying binary vectors containing the nptII marker gene and agrobacterial rolC and rolB oncogenes. Bacterial plasmid T-DNA-sea urchin DNA junction sites were identified in the genome of these embryos, thus indicating successful transformation. The nptII and both rol genes were expressed in the transformed embryos. The processes of transgene integration and transgene expression were suppressed when Agrobacteria contained mutated virA, virB or virG genes, suggesting that Agrobacterium transforms sea urchin cells by a mechanism similar to that which mediates T-DNA transfer to plants. Some of the embryos co-cultivated with Agrobacterium developed teratoma-like structures. The ability of Agrobacterium strains to trigger formation of teratoma-like structures was diminished when they contained the mutated vir genes. In summary, our results demonstrate that Agrobacterium is able to transform animal (sea urchin) embryonic cells, thus indicating a potential of this natural system for gene delivery to animal hosts. We also discuss the possibility of horizontal gene transfer from Agrobacterium to marine invertebrates.
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Affiliation(s)
- Victor P Bulgakov
- Bioengineering Group, Institute of Biology and Soil Science, Far East Branch of Russian Academy of Sciences, Vladivostok, Russia.
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26
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Cecchetti V, Pomponi M, Altamura MM, Pezzotti M, Marsilio S, D'Angeli S, Tornielli GB, Costantino P, Cardarelli M. Expression of rolB in tobacco flowers affects the coordinated processes of anther dehiscence and style elongation. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2004; 38:512-25. [PMID: 15086797 DOI: 10.1111/j.0960-7412.2004.02064.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The effect of auxin on stamen and pistil development in tobacco flowers was investigated by means of the localized expression of rolB (root loci B), an Agrobacterium oncogene that increases auxin sensitivity in a cell-autonomous fashion. When rolB is driven by the promoter of the meiosis-specific Arabidopsis gene DMC1 (disrupted meiotic cDNA 1), expression occurs earlier in male than in female developing organs, resulting in a delay in anther dehiscence with respect to normal timing of pistil development. As a consequence of this developmental uncoupling, self-pollination is prevented in pDMC1:rolB plants. Histological analysis of pDMC1:GFP plants indicates that in tobacco, this promoter is active not only in meiocytes but also in somatic tissues of the anther. In contrast, simultaneous expression of rolB in anther and pistil somatic tissues, achieved by expressing a construct containing rolB under the control of the promoter of the petunia gene FBP7 (floral binding protein 7), results in a concomitant delay of both anther dehiscence and pistil development without affecting self-pollination of the plants. Analysis of plants harboring the pFBP7:GUS construct shows that in tobacco, this promoter is active not only in the ovules, as described for petunia, but also in pistil and anther somatic tissues involved in the dehiscence program. The delay in anther dehiscence and pistil development could be phenocopied by exogenous application of auxin. Jasmonic acid (JA) could not rescue the delay in anther dehiscence. These results suggest that auxin plays a key role in the timing of anther dehiscence, the dehiscence program is controlled by the somatic tissues of the anther, and auxin also regulates pistil development.
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Affiliation(s)
- Valentina Cecchetti
- Istituto Pasteur Fondazione Cenci Bolognetti, Dipartimento di Genetica e Biologia Molecolare, Università La Sapienza, Piazzale Aldo Moro 5, 00185 Rome, Italy
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27
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Abstract
The term apomixis encompasses a suite of processes whereby seeds form asexually in plants. In contrast to sexual reproduction, seedlings arising from apomixis retain the genotype of the maternal parent. The transfer of apomixis and its effective utilization in crop plants (where it is largely absent) has major advantages in agriculture. The hallmark components of apomixis include female gamete formation without meiosis (apomeiosis), fertilization-independent embryo development (parthenogenesis), and developmental adaptations to ensure functional endosperm formation. Understanding the molecular mechanisms underlying apomixis, a developmentally fascinating phenomenon in plants, is critical for the successful induction and utilization of apomixis in crop plants. This review draws together knowledge gained from analyzing ovule, embryo, and endosperm development in sexual and apomictic plants. It consolidates the view that apomixis and sexuality are closely interrelated developmental pathways where apomixis can be viewed as a deregulation of the sexual process in both time and space.
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Affiliation(s)
- Anna M Koltunow
- Commonwealth Scientific and Industrial Research Organization, Plant Industry, P.O. Box 350, Glen Osmond, South Australia 5064, Australia.
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