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Xue JS, Qiu S, Jia XL, Shen SY, Shen CW, Wang S, Xu P, Tong Q, Lou YX, Yang NY, Cao JG, Hu JF, Shen H, Zhu RL, Murray JD, Chen WS, Yang ZN. Stepwise changes in flavonoids in spores/pollen contributed to terrestrial adaptation of plants. PLANT PHYSIOLOGY 2023; 193:627-642. [PMID: 37233029 DOI: 10.1093/plphys/kiad313] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 04/25/2023] [Accepted: 04/30/2023] [Indexed: 05/27/2023]
Abstract
Protecting haploid pollen and spores against UV-B light and high temperature, 2 major stresses inherent to the terrestrial environment, is critical for plant reproduction and dispersal. Here, we show flavonoids play an indispensable role in this process. First, we identified the flavanone naringenin, which serves to defend against UV-B damage, in the sporopollenin wall of all vascular plants tested. Second, we found that flavonols are present in the spore/pollen protoplasm of all euphyllophyte plants tested and that these flavonols scavenge reactive oxygen species to protect against environmental stresses, particularly heat. Genetic and biochemical analyses showed that these flavonoids are sequentially synthesized in both the tapetum and microspores during pollen ontogeny in Arabidopsis (Arabidopsis thaliana). We show that stepwise increases in the complexity of flavonoids in spores/pollen during plant evolution mirror their progressive adaptation to terrestrial environments. The close relationship between flavonoid complexity and phylogeny and its strong association with pollen survival phenotypes suggest that flavonoids played a central role in the progression of plants from aquatic environments into progressively dry land habitats.
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Affiliation(s)
- Jing-Shi Xue
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Shi Qiu
- Research and Development Center of Chinese Medicine Resources and Biotechnology, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Xin-Lei Jia
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Shi-Yi Shen
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Chong-Wen Shen
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Shui Wang
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Ping Xu
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Qi Tong
- Research and Development Center of Chinese Medicine Resources and Biotechnology, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Yu-Xia Lou
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Nai-Ying Yang
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Jian-Guo Cao
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Jin-Feng Hu
- Institute of Natural Medicine and Health Products, School of Pharmaceutical Sciences, Zhejiang Provincial Key Laboratory of Plant Ecology and Conservation, Taizhou University, Zhejiang 318000, PR China
| | - Hui Shen
- Shanghai Key Laboratory of Plant Functional Genomics and Resources, Shanghai Chenshan Botanical Garden, Shanghai 201602, China
| | - Rui-Liang Zhu
- Bryology Laboratory, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Jeremy D Murray
- National Key Laboratory of Plant Molecular Genetics, CAS-JIC Centre of Excellence for Plant and Microbial Science (CEPAMS), CAS Center for Excellence in Molecular and Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Wan-Sheng Chen
- Research and Development Center of Chinese Medicine Resources and Biotechnology, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Zhong-Nan Yang
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China
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Wang T, Bell BA, Fletcher WJ, Ryan PA, Wogelius RA. Influence of common palynological extraction treatments on ultraviolet absorbing compounds (UACs) in sub-fossil pollen and spores observed in FTIR spectra. Front Ecol Evol 2023. [DOI: 10.3389/fevo.2023.1096099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023] Open
Abstract
IntroductionBiological life, atmospheric circulation and the Earth’s climate may be influenced by UV-B radiation. In plants, Ultraviolet Absorbing Compounds (UACs) are an indicator of UV-B exposure, and the abundance of UACs in pollen and spores of embryophytes is measurable using Fourier Transform Infrared (FTIR) micro-Spectroscopy. However, understanding the influence of common chemical pre-treatments on sub-fossil pollen and spores with a view to UV-B reconstruction still requires investigation.MethodsHere, peat samples collected from a Late Holocene raised bog were treated with different chemicals (HCl, KOH, and acetolysis) for varying treatment times (up to 210 min). Pollen or spores of three common taxa (Alnus, Calluna and Sphagnum) were isolated and FTIR spectra obtained on individual grains. The spectra were compared to modern pollen and spore samples collected nearby.ResultsSpectra of modern and sub-fossil samples show several visible differences related to lipid and protoplast contents. The results of chemical treatments on sub-fossil pollen and spores reveal that HCl produced limited changes, while KOH and acetolysis altered several peaks, including the UAC-related aromatic peak at 1516 cm−1. We observe that all treatments modify the FTIR spectra to some degree, from weakest (HCl) to strongest (acetolysis). With respect to reduction of UAC peak area and treatment time, we observe in some cases a significant log-decay relationship, notably for KOH treatment on Calluna pollen and acetolysis on Sphagnum spores. Compared to untreated control samples, UAC peak area in Alnus, Calluna and Sphagnum reduced by 68%, 69% and 60% respectively, after only 3 min of acetolysis treatment. After 60 minutes of acetolysis treatment UAC peaks were reduced by 77%, 84% and 88%.DiscussionDue to the potential for taxon-specific effects and significant reductions in UAC peak area even within short treatment times, our recommendation for future applications in palaeoecological studies on palynomorph chemistry is to avoid chemical digestions in the pollen extraction process in favour of separation methods including micro-sieving and density separation.
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Kerienė I, Šaulienė I, Šukienė L, Judžentienė A, Ligor M, Buszewski B. Patterns of Phenolic Compounds in Betula and Pinus Pollen. PLANTS (BASEL, SWITZERLAND) 2023; 12:356. [PMID: 36679068 PMCID: PMC9865354 DOI: 10.3390/plants12020356] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/06/2023] [Accepted: 01/10/2023] [Indexed: 06/17/2023]
Abstract
In this study, phenolic compounds and their antioxidant activity in the pollen of anemophilous Betula and Pinus were determined. Spectrophotometric, high-performance thin-layer and liquid chromatography methods were applied. Free phenolic compounds (free PC) and phenolic compounds bound to the cell wall (bound PC) were analysed in the pollen extracts. Regardless of the pollen species, their content was 20% higher than that in bound PC extracts. Pinus pollen extracts contained 2.5 times less phenolic compounds compared to Betula. Free PC extraction from the deeper layers of Pinus pollen was minimal; the same content of phenolic compounds was obtained in both types of extracts. The bioactivity of pollen (p < 0.05) is related to the content of phenolic compounds and flavonoids in Betula free PC and in bound PC, and only in free PC extracts of Pinus. Rutin, chlorogenic and trans-ferulic acids were characterised by antioxidant activity. Phenolic acids accounted for 70−94%, while rutin constituted 2−3% of the total amount in the extracts. One of the dominant phenolic acids was trans-ferulic acid in all the Betula and Pinus samples. The specific compounds were vanillic and chlorogenic acids of Betula pollen extracts, while Pinus extracts contained gallic acid. The data obtained for the phenolic profiles and antioxidant activity of Betula and Pinus pollen can be useful for modelling food chains in ecosystems.
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Affiliation(s)
- Ilona Kerienė
- Regional Development Institute, Šiauliai Academy, Vilnius University, 84 Vytauto Str., LT-76352 Šiauliai, Lithuania
| | - Ingrida Šaulienė
- Regional Development Institute, Šiauliai Academy, Vilnius University, 84 Vytauto Str., LT-76352 Šiauliai, Lithuania
| | - Laura Šukienė
- Regional Development Institute, Šiauliai Academy, Vilnius University, 84 Vytauto Str., LT-76352 Šiauliai, Lithuania
| | - Asta Judžentienė
- Center for Physical Sciences and Technology, Department of Organic Chemistry, Saulėtekio Avenue 3, LT-10257 Vilnius, Lithuania
- Life Sciences Center, Institute of Biosciences, Vilnius University, Saulėtekio Avenue 7, LT-10257 Vilnius, Lithuania
| | - Magdalena Ligor
- Department of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University, 7 Gagarina Str., 87-100 Torun, Poland
| | - Bogusław Buszewski
- Department of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University, 7 Gagarina Str., 87-100 Torun, Poland
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D'Agostino A, Di Marco G, Marvelli S, Marchesini M, Rizzoli E, Rolfo MF, Canini A, Gismondi A. Neolithic dental calculi provide evidence for environmental proxies and consumption of wild edible fruits and herbs in central Apennines. Commun Biol 2022; 5:1384. [PMID: 36536113 PMCID: PMC9763411 DOI: 10.1038/s42003-022-04354-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 12/08/2022] [Indexed: 12/23/2022] Open
Abstract
Looking for a biological fingerprint relative to new aspects of the relationship between humans and natural environment during prehistoric times is challenging. Although many issues still need to be addressed in terms of authentication and identification, microparticles hidden in ancient dental calculus can provide interesting information for bridging this gap of knowledge. Here, we show evidence about the role of edible plants for the early Neolithic individuals in the central Apennines of the Italian peninsula and relative cultural landscape. Dental calculi from human and animal specimens exhumed at Grotta Mora Cavorso (Lazio), one of the largest prehistoric burial deposits, have returned an archaeobotanical record made up of several types of palaeoecological proxies. The organic fraction of this matrix was investigated by a multidisciplinary approach, whose novelty consisted in the application of next generation sequencing to ancient plant DNA fragments, specifically codifying for maturase K barcode gene. Panicoideae and Triticeae starches, together with genetic indicators of Rosaceae fruits, figs, and Lamiaceae herbs, suggested subsistence practices most likely still based on wild plant resources. On the other hand, pollen, and non-pollen palynomorphs allowed us to outline a general vegetational framework dominated by woodland patches alternated with meadows, where semi-permanent settlements could have been established.
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Affiliation(s)
- Alessia D'Agostino
- PhD Program in Evolutionary Biology and Ecology, Department of Biology, University of Rome Tor Vergata, Rome, Italy
- Laboratory of Botany, Department of Biology, University of Rome "Tor Vergata", Rome, Italy
| | - Gabriele Di Marco
- Laboratory of Botany, Department of Biology, University of Rome "Tor Vergata", Rome, Italy
| | - Silvia Marvelli
- Laboratorio di Palinologia e Archeobotanica-C.A.A. Giorgio Nicoli, San Giovanni in Persiceto, Bologna, Italy
| | - Marco Marchesini
- Laboratorio di Palinologia e Archeobotanica-C.A.A. Giorgio Nicoli, San Giovanni in Persiceto, Bologna, Italy
| | - Elisabetta Rizzoli
- Laboratorio di Palinologia e Archeobotanica-C.A.A. Giorgio Nicoli, San Giovanni in Persiceto, Bologna, Italy
| | - Mario Federico Rolfo
- Department of History, Culture and Society, University of Rome "Tor Vergata", Rome, Italy
| | - Antonella Canini
- Laboratory of Botany, Department of Biology, University of Rome "Tor Vergata", Rome, Italy
| | - Angelo Gismondi
- Laboratory of Botany, Department of Biology, University of Rome "Tor Vergata", Rome, Italy.
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Dhara A, Raichaudhuri A. ABCG transporter proteins with beneficial activity on plants. PHYTOCHEMISTRY 2021; 184:112663. [PMID: 33550197 DOI: 10.1016/j.phytochem.2021.112663] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 01/03/2021] [Accepted: 01/06/2021] [Indexed: 05/20/2023]
Abstract
Among the several subfamilies of ABC transporters the ABC-G subfamily is very significant. In the model plant Arabidopsis thaliana itself, ABCG subfamily houses highest number of transporters with mostly half-size transporters (called WBC) and fewer full-size transporters (called PDR). During drought stress the stress hormone abscisic acid (ABA) is exported from the root xylem and imported by the leaf stomatal cells by ABCG transporter proteins to reduce the transpiration of water from leaves. Moreover, the ABCG transporters play a chief role in export of prime biotic stress induced hormones like jasmonic acid and salicylic acid among other secondary metabolites. In this way they protect the plant as the first line of defense against pathogenic damages. The ABCG transporters help the plant in becoming kanamycin resistant which help in plant growth. ABCG transporters of Nicotiana plumbaginifolia provide resistance to pathogens like Pseudomonas syringae. Furthermore several ABCG transporters of A. thaliana are efficient in transporting cuticular lipids like cutin to help development of cuticle. Pollen exine wall formation is also aided by one ABCG transporter itself. Some important ABCG transporters like ABCG36 and ABCG40 have been suggested to contribute hugely towards heavy metal resistance and cellular detoxification in Arabidopsis thaliana.
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Affiliation(s)
- Anindita Dhara
- Amity Institute of Biotechnology, Amity University, New Town, Kolkata, 700135, India
| | - Ayan Raichaudhuri
- Amity Institute of Biotechnology, Amity University, New Town, Kolkata, 700135, India.
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Gabarayeva NI, Grigorjeva VV. An integral insight into pollen wall development: involvement of physical processes in exine ontogeny in Calycanthus floridus L., with an experimental approach. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 105:736-753. [PMID: 33155350 DOI: 10.1111/tpj.15070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 09/29/2020] [Accepted: 10/02/2020] [Indexed: 06/11/2023]
Abstract
We aimed to understand the underlying mechanisms of development in the sporopollenin-containing part of the pollen wall, the exine, one of the most complex cell walls in plants. Our hypothesis is that distinct physical processes, phase separation and micellar self-assembly, underpinexine development by taking the molecular building blocks, determined and synthesised by the genome, through several phase transitions. To test this hypothesis, we traced each stage of microspore development in Calycanthus floridus with transmission electron microscopy and then generated in vitro experimental simulations corresponding to every developmental stage. The sequence of structures observed within the periplasmic space around developing microspores starts with spherical units, which are rearranged into columns to then form rod-like units (the young columellae) and, finally, white line centred endexine lamellae. Phase separation precedes each developmental stage. The set of experimental simulations, obtained as self-assembled micellar mesophases formed at the interface between lipid and water compartments, was the same: spherical micelles; columns of spherical micelles; cylindrical micelles; and laminate micelles, separated by gaps, resembling white-lined lamellae. Thus, patterns simulating structures observed at the main stages of exine development in C. floridus were obtained from in vitro experiments, and hence purely physicochemical processes can construct exine-like patterns. This highlights the important part played by physical processes that are not under direct genomic control and share influence on the emerging ultrastructure with the genome during exine development. These findings suggest that a new approach to ontogenetic studies, including a consideration of physical factors, is required for a better understanding of developmental processes.
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Affiliation(s)
- Nina I Gabarayeva
- Komarov Botanical Institute, Popov St. 2, St.-Petersburg, 197376, Russia
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Comparison of the Micromorphology and Ultrastructure of Pollen Grains of Selected Rubus idaeus L. Cultivars Grown in Commercial Plantation. PLANTS 2020; 9:plants9091194. [PMID: 32932712 PMCID: PMC7570156 DOI: 10.3390/plants9091194] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/04/2020] [Accepted: 09/10/2020] [Indexed: 11/16/2022]
Abstract
The genus Rubus is one of the largest taxonomically diverse and complex genera in the family Rosaceae. Morphology of pollen grains (equatorial and polar axes length, shape and size, aperture position, exine sculpture, perforations) is regarded as one of its main diagnostic features for identification of species and varieties. An attempt was made to fill the gap concerning the pollen micromorphology and ultrastructure of R. idaeus L. using light, scanning, and electron transmission microscopy. This study is a comparative analysis of micromorphological and ultrastructural traits of pollen from six raspberry cultivars. The pollen grains were classified as small or medium of shape prolato-spheroids. The parallel striae in the equatorial view in the exine sculpture were sometimes branched dichotomously in ‘Glen Ample’, ‘Polka’, and ‘Polana’, arcuate in ‘Laszka’ and ‘Pokusa’, or irregularly overlapping in ‘Radziejowa’. The width of exine striae of biennial fruiting cultivars was much larger than in repeated fruiting cultivars. In terms of the increasing number of perforations per unit area of the exine surface, the cultivars were ranked as follows: ‘Pokusa’ < ‘Glen Ample’ < ‘Laszka’ < ‘Polka’ < ‘Polana’ < ‘Radziejowa’. The thickest tectum, the highest and thickest columellae with the largest distances between them, and the thicker foot layer were demonstrated in ‘Glen Ample’. The ectoexine constituted on average ca. 78–90% of the exine thickness. The findings may constitute auxiliary traits i.a. for identification of related taxa, interpretation of phylogenetic relationships, and pollination biology.
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Xiong YZ, Jia LB, Zhang C, Huang SQ. Color-matching between pollen and corolla: hiding pollen via visual crypsis? THE NEW PHYTOLOGIST 2019; 224:1142-1150. [PMID: 31225909 DOI: 10.1111/nph.16012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 06/14/2019] [Indexed: 06/09/2023]
Abstract
Visual signals attractive to friends may also attract enemies. The bright colors of anthers and pollen have generally been thought to attract pollinators. We hypothesize that visual crypsis of anthers, and particularly pollen, should be favored in flowering plants because protection from pollen collectors reduces the loss of male gametes. To understand adaptive strategies relating to the color of pollen, we measured the color of pollen, undehisced anther sacs, and their background, the corolla, with a spectrometer for 104 insect-pollinated flowering species from a natural community in Hengduan Mountains, southwest China. The colors of anthers, pollen and corollas were diverse in these species. The color diversity of exposed pollen was significantly higher than that of concealed pollen (i.e. where anthers are enclosed or shielded by corollas). The color contrast between pollen and corolla was significantly smaller in species with exposed pollen than in those with concealed pollen. Unlike anther color, exposed pollen color tended to match its background corolla color. Our phylogenetic comparative analysis showed contrasting effects of pollen color patterns between flowers with exposed pollen and those with concealed pollen, revealing a strategy of hiding pollen from pollen thieves via visual crypsis.
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Affiliation(s)
- Ying-Ze Xiong
- Institute of Evolution and Ecology, School of Life Sciences, Central China Normal University, Wuhan, New England Biolabs, 430079, China
| | - Li-Bing Jia
- Institute of Evolution and Ecology, School of Life Sciences, Central China Normal University, Wuhan, New England Biolabs, 430079, China
| | - Chuan Zhang
- Institute of Evolution and Ecology, School of Life Sciences, Central China Normal University, Wuhan, New England Biolabs, 430079, China
| | - Shuang-Quan Huang
- Institute of Evolution and Ecology, School of Life Sciences, Central China Normal University, Wuhan, New England Biolabs, 430079, China
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Peng H, Meyer RS, Yang T, Whitaker BD, Trouth F, Shangguan L, Huang J, Litt A, Little DP, Ke H, Jurick WM. A novel hydroxycinnamoyl transferase for synthesis of hydroxycinnamoyl spermine conjugates in plants. BMC PLANT BIOLOGY 2019; 19:261. [PMID: 31208339 PMCID: PMC6580504 DOI: 10.1186/s12870-019-1846-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 05/22/2019] [Indexed: 05/03/2023]
Abstract
BACKGROUND Hydroxycinnamoyl-spermine conjugates (HCSpm) are a class of hydroxycinnamic acid amides (HCAAs), which not only are instrumental in plant development and stress response, but also benefit human health. However, HCSpm are not commonly produced in plants, and the mechanism of their biosynthesis remains unclear. In previous investigations of phenolics in Solanum fruits related to eggplant (Solanum melongena L.), we discovered that Solanum richardii, an African wild relative of eggplant, was rich in HCSpms in fruits. RESULTS The putative spermine hydroxycinnamoyl transferase (HT) SpmHT was isolated from S. richardii and eggplant. SrSpmHT expression was high in flowers and fruit, and was associated with HCSpm accumulation in S. richardii; however, SpmHT was hardly detected in eggplant cultivars and other wild relatives. Recombinant SpmHT exclusively selected spermine as the acyl acceptor substrate, while showing donor substrate preference in the following order: caffeoyl-CoA, feruloyl-CoA, and p-coumaroyl-CoA. Molecular docking revealed that substrate binding pockets of SpmHT could properly accommodate spermine but not the shorter, more common spermidine. CONCLUSION SrSpmHT is a novel spermine hydroxycinnamoyl transferase that uses Spm exclusively as the acyl acceptor substrate to produce HCSpms. Our findings shed light on the HCSpm biosynthetic pathway that may allow an increase of health beneficial metabolites in Solanum crops via methods such as introgression or engineering HCAA metabolism.
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Affiliation(s)
- Hui Peng
- Food Quality Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service of U.S. Department of Agriculture, Beltsville, MD 20705 USA
- The Genome Center and Department of Plant Sciences, University of California, Davis, CA 95616 USA
| | - Rachel S. Meyer
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA 90095 USA
| | - Tianbao Yang
- Food Quality Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service of U.S. Department of Agriculture, Beltsville, MD 20705 USA
| | - Bruce D. Whitaker
- Food Quality Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service of U.S. Department of Agriculture, Beltsville, MD 20705 USA
| | - Frances Trouth
- Food Quality Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service of U.S. Department of Agriculture, Beltsville, MD 20705 USA
| | - Lingfei Shangguan
- Food Quality Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service of U.S. Department of Agriculture, Beltsville, MD 20705 USA
- College of Horticulture, Nanjing Agricultural University, Nanjing, 210095 Jiangsu China
| | - Jingbing Huang
- College of Food Science and Engineering, Huazhong Agricultural University, Wuhan, 430070 Hubei China
| | - Amy Litt
- College of Natural and Agricultural Sciences, University of California, Riverside, CA 92521 USA
| | - Damon P. Little
- Cullman Program for Molecular Systematics, New York Botanical Garden, 2900 Southern Boulevard, Bronx, New York, NY 10458 USA
| | - Hengming Ke
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Wayne M. Jurick
- Food Quality Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service of U.S. Department of Agriculture, Beltsville, MD 20705 USA
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Grigorjeva VV, Gabarayeva N. Pollen wall ontogeny in Polemonium caeruleum (Polemoniaceae) and suggested underlying mechanisms of development. PROTOPLASMA 2018; 255:109-128. [PMID: 28667410 DOI: 10.1007/s00709-017-1121-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 05/07/2017] [Indexed: 06/07/2023]
Abstract
By a detailed ontogenetic study of Polemonium caeruleum pollen, tracing each stage of development at high TEM resolution, we aim to understand the establishment of the pollen wall and to unravel the mechanisms underlying sporoderm development. The main steps of exine ontogeny in Polemonium caeruleum, observed in the microspore periplasmic space, are spherical units, gradually transforming into columns, then to rod-like units (procolumellae), the appearance of the initial tectum, growth of columellae in height and tectum in thickness and initial sporopollenin accumulation on them, the appearance of the endexine lamellae and of dark-contrasted particles on the tectum, the appearance of a sponge-like layer and of the intine in aperture sites, the appearance of the foot layer on the base of the sponge-like layer and of spinules on the tectum, and massive sporopollenin accumulation. This sequence of developmental events fits well to the sequence of self-assembling micellar mesophases. This gives (together with earlier findings and experimental exine simulations) strong evidence that genome and self-assembly probably share control of exine formation. It is highly probable that self-assembly is an intrinsic instrument of evolution.
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Affiliation(s)
- Valentina V Grigorjeva
- Komarov Botanical Institute of Russian Academy of Sciences, Popov St. 2, 197376, St. Petersburg, Russia
| | - Nina Gabarayeva
- Komarov Botanical Institute of Russian Academy of Sciences, Popov St. 2, 197376, St. Petersburg, Russia.
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Gabarayeva NI, Grigorjeva VV. Self-assembly as the underlying mechanism for exine development in Larix decidua D. C. PLANTA 2017; 246:471-493. [PMID: 28477281 DOI: 10.1007/s00425-017-2702-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 04/24/2017] [Indexed: 06/07/2023]
Abstract
Our findings suggest a new approach to pollen ontogenetic investigations, entailing consideration of physical factors, which enable a better understanding of exine developmental processes. The sporopollenin-containing part of the pollen wall-the exine-is one of the most complex cell walls in plants. By tracing each stage of microspore development in Larix decidua with TEM, we aimed to understand the underlying mechanisms of its exine establishment. Our hypothesis is that self-assembly interferes with exine development. Our specific aim is to generate experimental simulations of the exine developmental pattern. The sequence of events leading to exine development includes the appearance of spherical units in the periplasmic space, their rearrangement into radial columns, and the appearance of white-lined endexine lamellae. The final accumulation of sporopollenin proceeds in the post-tetrad period. The sequence of self-assembling micellar mesophases corresponds with that of the developmental events: spherical micelles; columns of spherical micelles; and laminate micelles separated by strata of water and visible as white-lined lamellae in TEM. Several patterns, simulating structures at different stages of exine development in Larix, were obtained from in vitro experiments. Purely physicochemical processes of self-assembly, which are not under direct genetic control, play an important role in exine development and share control with the genome. These findings suggest that a new approach to ontogenetic investigations, entailing consideration of physical factors (e.g., cell tensegrity), is required for a better understanding of developmental processes.
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Affiliation(s)
- Nina I Gabarayeva
- Komarov Botanical Institute of Russian Academy of Sciences, Popov St. 2, St. Petersburg, 197376, Russia.
| | - Valentina V Grigorjeva
- Komarov Botanical Institute of Russian Academy of Sciences, Popov St. 2, St. Petersburg, 197376, Russia
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Prabhakar AK, Lai HY, Potroz MG, Corliss MK, Park JH, Mundargi RC, Cho D, Bang SI, Cho NJ. Chemical processing strategies to obtain sporopollenin exine capsules from multi-compartmental pine pollen. J IND ENG CHEM 2017. [DOI: 10.1016/j.jiec.2017.05.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Park JH, Seo J, Jackman JA, Cho NJ. Inflated Sporopollenin Exine Capsules Obtained from Thin-Walled Pollen. Sci Rep 2016; 6:28017. [PMID: 27302853 PMCID: PMC4908411 DOI: 10.1038/srep28017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 05/17/2016] [Indexed: 11/29/2022] Open
Abstract
Sporopollenin is a physically robust and chemically resilient biopolymer that comprises the outermost layer of pollen walls and is the first line of defense against harsh environmental conditions. The unique physicochemical properties of sporopollenin increasingly motivate the extraction of sporopollenin exine capsules (SECs) from pollen walls as a renewable source of organic microcapsules for encapsulation applications. Despite the wide range of different pollen species with varying sizes and wall thicknesses, faithful extraction of pollen-mimetic SECs has been limited to thick-walled pollen capsules with rigid mechanical properties. There is an unmet need to develop methods for producing SECs from thin-walled pollen capsules which constitute a large fraction of all pollen species and have attractive materials properties such as greater aerosol dispersion. Herein, we report the first successful extraction of inflated SEC microcapsules from a thin-walled pollen species (Zea mays), thereby overcoming traditional challenges with mechanical stability and loss of microstructure. Morphological and compositional characterization of the SECs obtained by the newly developed extraction protocol confirms successful protein removal along with preservation of nanoscale architectural features. Looking forward, there is excellent potential to apply similar strategies across a wide range of unexplored thin-walled pollen species.
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Affiliation(s)
- Jae Hyeon Park
- School of Materials Science and Engineering Nanyang Technological University, 50 Nanyang Avenue 639798, Singapore
- Centre for Biomimetic Sensor Science, Nanyang Technological University, 50 Nanyang Drive 637553, Singapore
| | - Jeongeun Seo
- School of Materials Science and Engineering Nanyang Technological University, 50 Nanyang Avenue 639798, Singapore
- Centre for Biomimetic Sensor Science, Nanyang Technological University, 50 Nanyang Drive 637553, Singapore
| | - Joshua A. Jackman
- School of Materials Science and Engineering Nanyang Technological University, 50 Nanyang Avenue 639798, Singapore
- Centre for Biomimetic Sensor Science, Nanyang Technological University, 50 Nanyang Drive 637553, Singapore
| | - Nam-Joon Cho
- School of Materials Science and Engineering Nanyang Technological University, 50 Nanyang Avenue 639798, Singapore
- Centre for Biomimetic Sensor Science, Nanyang Technological University, 50 Nanyang Drive 637553, Singapore
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive 637459, Singapore
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Edlund AF, Zheng Q, Lowe N, Kuseryk S, Ainsworth KL, Lyles RH, Sibener SJ, Preuss D. Pollen from Arabidopsis thaliana and other Brassicaceae are functionally omniaperturate. AMERICAN JOURNAL OF BOTANY 2016; 103:1006-19. [PMID: 27335390 DOI: 10.3732/ajb.1600031] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2016] [Accepted: 05/23/2016] [Indexed: 05/06/2023]
Abstract
PREMISE OF THE STUDY Most pollen walls are interrupted by apertures, thin areas providing access to stigmatic fluids and exit points for pollen tubes. Unexpectedly, pollen tubes of Arabidopsis thaliana are not obligated to pass through apertures and can instead take the shortest route into the stigma, passing directly through a nonaperturate wall. METHODS We used stains and confocal microscopy to follow early pollen tube formation in A. thaliana and 200+ other species. We germinated pollen in vitro and in situ (at control and high humidities) and also used atomic force microscopy to assay material properties of nonaperture and aperture walls. KEY RESULTS Pollen tubes of A. thaliana breached nonaperture walls despite these being an order of magnitude stiffer than aperture walls. Breakout was associated with localized swelling of the pectin-rich (alcian blue positive) intine. The precision of pollen tube exit at the pollen-stigma interface was lost at high humidity. Pollen from ∼4% of the species surveyed exhibited breakout germination behavior; all nine breakout species identified so far are in the Brassicaceae family (∼25% of the Brassicaceae sampled) and are scattered across seven tribes. CONCLUSIONS The polarity of pollen germination in A. thaliana is externally induced, not linked to aperture location. The biomechanical force for breaking nonaperture walls is found in localized swelling of intine pectins. As such, the pollen from A. thaliana, and likely many Brassicaceae family members, are functionally omniaperturate. This new mechanism for germination between extant apertures raises questions about exine porosity and the diversity of mechanisms across taxa.
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Affiliation(s)
- Anna F Edlund
- Biology Department, Lafayette College, Easton, Pennsylvania 18042 USA
| | - Qin Zheng
- The James Franck Institute and Department of Chemistry, University of Chicago, 929 East 57th Street, Chicago, Illinois 60637 USA
| | - Nancy Lowe
- Biology Department, Spelman College, 350 Spelman Lane, Atlanta, Georgia 30314 USA
| | - Skye Kuseryk
- Biology Department, Lafayette College, Easton, Pennsylvania 18042 USA
| | - Krystle L Ainsworth
- Biology Department, Spelman College, 350 Spelman Lane, Atlanta, Georgia 30314 USA
| | - Robert H Lyles
- Biostatistics Department, Rollins School of Public Health, Emory University, Atlanta, Georgia 30322 USA
| | - Steven J Sibener
- The James Franck Institute and Department of Chemistry, University of Chicago, 929 East 57th Street, Chicago, Illinois 60637 USA
| | - Daphne Preuss
- Molecular Genetics and Cell Biology Department, University of Chicago, Chicago, Illinois 60637 USA
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Dong J, Gao K, Wang K, Xu X, Zhang H. Cell Wall Disruption of Rape Bee Pollen Treated with Combination of Protamex Hydrolysis and Ultrasonication. Food Res Int 2015; 75:123-130. [DOI: 10.1016/j.foodres.2015.05.039] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 05/19/2015] [Accepted: 05/27/2015] [Indexed: 12/01/2022]
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16
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Fellenberg C, Vogt T. Evolutionarily conserved phenylpropanoid pattern on angiosperm pollen. TRENDS IN PLANT SCIENCE 2015; 20:212-8. [PMID: 25739656 DOI: 10.1016/j.tplants.2015.01.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 01/27/2015] [Accepted: 01/31/2015] [Indexed: 05/22/2023]
Abstract
The male gametophyte of higher plants appears as a solid box containing the essentials to transmit genetic material to the next generation. These consist of haploid generative cells that are required for reproduction, and an invasive vegetative cell producing the pollen tube, both mechanically protected by a rigid polymer, the pollen wall, and surrounded by a hydrophobic pollen coat. This coat mediates the direct contact to the biotic and abiotic environments. It contains a mixture of compounds required not only for fertilization but also for protection against biotic and abiotic stressors. Among its metabolites, the structural characteristics of two types of phenylpropanoids, hydroxycinnamic acid amides and flavonol glycosides, are highly conserved in Angiosperm pollen. Structural and functional aspects of these compounds will be discussed.
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Affiliation(s)
- Christin Fellenberg
- Leibniz Institute of Plant Biochemistry, Department of Cell and Metabolic Biology, Weinberg 3, 06120 Halle (Saale), Germany; Department of Biology, Centre for Forest Biology, University of Victoria, Station CSC, Box 3020, Victoria, BC V8W 3N5, Canada
| | - Thomas Vogt
- Leibniz Institute of Plant Biochemistry, Department of Cell and Metabolic Biology, Weinberg 3, 06120 Halle (Saale), Germany.
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17
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Jia QS, Zhu J, Xu XF, Lou Y, Zhang ZL, Zhang ZP, Yang ZN. Arabidopsis AT-hook protein TEK positively regulates the expression of arabinogalactan proteins for Nexine formation. MOLECULAR PLANT 2015; 8:251-60. [PMID: 25616387 DOI: 10.1016/j.molp.2014.10.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Revised: 08/19/2014] [Accepted: 10/03/2014] [Indexed: 05/08/2023]
Abstract
Nexine is a conserved layer of the pollen wall. We previously reported that the nexine layer is absent in the knockout mutant of Arabidopsis TRANSPOSABLE ELEMENT SILENCING VIA AT-HOOK (TEK) gene. In this study, we investigated the molecular regulatory functions of TEK in pollen development and identified the genes encoding Arabinogalactan proteins (AGPs) as direct targets of TEK, which are essential for nexine formation. Phenotypic similarity between tek and the TEK-SRDX transgenic lines suggest that TEK plays a role in transcriptional activation in anther development. Microarray analysis identified a total of 661 genes downregulated in tek, including four genes encoding AGPs, AGP6, AGP11, AGP23, and AGP40. Electrophoretic mobility shift assays showed that TEK could directly bind the nuclear matrix attachment region (MAR) and the promoter of AGP6. Chromatin immunoprecipitation followed by PCR analysis demonstrated that TEK is enriched in the promoters of the four AGP genes. Expression of AGP6 driven by the TEK promoter in tek partially rescued both nexine formation and plant fertility. These results indicate that TEK directly regulates AGP expression in the anther to control nexine layer formation. We also proposed that glycoproteins might be essential components of the nexine layer in the pollen wall.
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Affiliation(s)
- Qi-Shi Jia
- College of Life and Environment Sciences, Shanghai Normal University, Shanghai 200234, China; College of Agriculture, Henan University of Science and Technology, Luoyang 471003, China
| | - Jun Zhu
- College of Life and Environment Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Xiao-Feng Xu
- College of Life and Environment Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Yue Lou
- College of Life and Environment Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Zhan-Lin Zhang
- College of Life and Environment Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Zhi-Ping Zhang
- National Key Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Zhong-Nan Yang
- College of Life and Environment Sciences, Shanghai Normal University, Shanghai 200234, China.
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de Souza SP, Bassut J, Marquez HV, Junior II, Miranda LSM, Huang Y, Mackenzie G, Boa AN, de Souza ROMA. Sporopollenin as an efficient green support for covalent immobilization of a lipase. Catal Sci Technol 2015. [DOI: 10.1039/c4cy01682c] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Aminoalkyl functionalised sporopollenin exine capsules have been used to immobilizeCandida antarcticalipase B using a covalent diimine-based linker.
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Affiliation(s)
- Stefânia P. de Souza
- Biocatalysis and Organic Synthesis Group
- Chemistry Institute
- Federal University of Rio de Janeiro
- Brazil
| | - Jonathan Bassut
- Biocatalysis and Organic Synthesis Group
- Chemistry Institute
- Federal University of Rio de Janeiro
- Brazil
| | - Heiddy V. Marquez
- Biocatalysis and Organic Synthesis Group
- Chemistry Institute
- Federal University of Rio de Janeiro
- Brazil
| | - Ivaldo I. Junior
- Biocatalysis and Organic Synthesis Group
- Chemistry Institute
- Federal University of Rio de Janeiro
- Brazil
| | - Leandro S. M. Miranda
- Biocatalysis and Organic Synthesis Group
- Chemistry Institute
- Federal University of Rio de Janeiro
- Brazil
| | - Youkui Huang
- Department of Chemistry
- University of Hull
- Kingston upon Hull
- UK
| | | | - Andrew N. Boa
- Department of Chemistry
- University of Hull
- Kingston upon Hull
- UK
| | - Rodrigo O. M. A. de Souza
- Biocatalysis and Organic Synthesis Group
- Chemistry Institute
- Federal University of Rio de Janeiro
- Brazil
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Gabarayeva NI, Grigorjeva VV. Sporoderm and tapetum development in Eupomatia laurina (Eupomatiaceae). An interpretation. PROTOPLASMA 2014; 251:1321-45. [PMID: 24671645 DOI: 10.1007/s00709-014-0631-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 03/01/2014] [Indexed: 05/05/2023]
Abstract
For the first time, the developmental events in the course of exine structure establishment have been traced in detail with TEM in Eupomatia, with the addition of cytochemical tests. A new look at unfolding events is suggested using our recent hypothesis on self-assembling micellar mesophases. The process proved to be unusual and includes "ghost" stages. The first units observed in the periplasmic space are spherical ones (= normal spherical micelles). These accumulate, resulting in a granular layer up to middle tetrad stage. Sporopollenin precursor accumulation on these units makes the ectexine layer looking as homogenous at late tetrad stage. Simultaneously, the columns of globules are added in the periplasmic space, which reminds an attempt to form columellae; but, the process failed. Instead, a fimbrillate endexine layer of compressed globules appears. The latter augments via additional globules, appearing in the periplasmic space in the free microspore period. The endexine formation is double-stepped spatially and temporally. The second, lamellate endexine layer (laminate micelles) appears late in development, when the channeled intine-I is already established-a very unusual feature. Moreover, a "fenestrated" stage comes unexpectedly at vacuolate stage, when hitherto amorphous ectexine appears pierced by cavernae-the results of reversal of normal spherical micelles (constituents of ectexine) to reverse the ones that open their cores for the entrance of hydrophilic nutrients from tapetum and give them over to the microspore cytoplasm by exchanging their solubilizates.
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Affiliation(s)
- Nina I Gabarayeva
- Komarov Botanical Institute, Popov st. 2, 197376, St. Petersburg, Russia,
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20
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Xu J, Ding Z, Vizcay-Barrena G, Shi J, Liang W, Yuan Z, Werck-Reichhart D, Schreiber L, Wilson ZA, Zhang D. ABORTED MICROSPORES Acts as a Master Regulator of Pollen Wall Formation in Arabidopsis. THE PLANT CELL 2014; 26:1544-1556. [PMID: 24781116 PMCID: PMC4036570 DOI: 10.1105/tpc.114.122986] [Citation(s) in RCA: 160] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 03/18/2014] [Accepted: 04/11/2014] [Indexed: 05/18/2023]
Abstract
Mature pollen is covered by durable cell walls, principally composed of sporopollenin, an evolutionary conserved, highly resilient, but not fully characterized, biopolymer of aliphatic and aromatic components. Here, we report that ABORTED MICROSPORES (AMS) acts as a master regulator coordinating pollen wall development and sporopollenin biosynthesis in Arabidopsis thaliana. Genome-wide coexpression analysis revealed 98 candidate genes with specific expression in the anther and 70 that showed reduced expression in ams. Among these 70 members, we showed that AMS can directly regulate 23 genes implicated in callose dissociation, fatty acids elongation, formation of phenolic compounds, and lipidic transport putatively involved in sporopollenin precursor synthesis. Consistently, ams mutants showed defective microspore release, a lack of sporopollenin deposition, and a dramatic reduction in total phenolic compounds and cutin monomers. The functional importance of the AMS pathway was further demonstrated by the observation of impaired pollen wall architecture in plant lines with reduced expression of several AMS targets: the abundant pollen coat protein extracellular lipases (EXL5 and EXL6), and CYP98A8 and CYP98A9, which are enzymes required for the production of phenolic precursors. These findings demonstrate the central role of AMS in coordinating sporopollenin biosynthesis and the secretion of materials for pollen wall patterning.
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Affiliation(s)
- Jie Xu
- Collaborative Innovation Center for Genetics and Development, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zhiwen Ding
- Collaborative Innovation Center for Genetics and Development, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Gema Vizcay-Barrena
- School of Biosciences, University of Nottingham, Loughborough, Leicestershire, LE125RD, United Kingdom
| | - Jianxin Shi
- Collaborative Innovation Center for Genetics and Development, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Wanqi Liang
- Collaborative Innovation Center for Genetics and Development, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zheng Yuan
- Collaborative Innovation Center for Genetics and Development, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Danièle Werck-Reichhart
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, Unité Propre de Recherche 2357-Université de Strasbourg, 67083 Strasbourg Cedex, France
| | - Lukas Schreiber
- Institute of Cellular and Molecular Botany, University of Bonn, D-53115 Bonn, Germany
| | - Zoe A Wilson
- School of Biosciences, University of Nottingham, Loughborough, Leicestershire, LE125RD, United Kingdom
| | - Dabing Zhang
- Collaborative Innovation Center for Genetics and Development, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
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Diego-Taboada A, Beckett ST, Atkin SL, Mackenzie G. Hollow pollen shells to enhance drug delivery. Pharmaceutics 2014; 6:80-96. [PMID: 24638098 PMCID: PMC3978527 DOI: 10.3390/pharmaceutics6010080] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 03/05/2014] [Accepted: 03/06/2014] [Indexed: 11/21/2022] Open
Abstract
Pollen grain and spore shells are natural microcapsules designed to protect the genetic material of the plant from external damage. The shell is made up of two layers, the inner layer (intine), made largely of cellulose, and the outer layer (exine), composed mainly of sporopollenin. The relative proportion of each varies according to the plant species. The structure of sporopollenin has not been fully characterised but different studies suggest the presence of conjugated phenols, which provide antioxidant properties to the microcapsule and UV (ultraviolet) protection to the material inside it. These microcapsule shells have many advantageous properties, such as homogeneity in size, resilience to both alkalis and acids, and the ability to withstand temperatures up to 250 °C. These hollow microcapsules have the ability to encapsulate and release actives in a controlled manner. Their mucoadhesion to intestinal tissues may contribute to the extended contact of the sporopollenin with the intestinal mucosa leading to an increased efficiency of delivery of nutraceuticals and drugs. The hollow microcapsules can be filled with a solution of the active or active in a liquid form by simply mixing both together, and in some cases operating a vacuum. The active payload can be released in the human body depending on pressure on the microcapsule, solubility and/or pH factors. Active release can be controlled by adding a coating on the shell, or co-encapsulation with the active inside the shell.
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23
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Diego-Taboada A, Maillet L, Banoub JH, Lorch M, Rigby AS, Boa AN, Atkin SL, Mackenzie G. Protein free microcapsules obtained from plant spores as a model for drug delivery: ibuprofen encapsulation, release and taste masking. J Mater Chem B 2012; 1:707-713. [PMID: 32260776 DOI: 10.1039/c2tb00228k] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Sporopollenin exine capsules (SEC) extracted from Lycopodium clavatum spores were shown to encapsulate ibuprofen as a drug model, with 97 ± 1% efficiency as measured by recovery of the loaded drug and absence of the drug on the SEC surface by scanning electron microscopy (SEM). The encapsulated ibuprofen was shown to be unchanged from its bulk crystalline form by solid state NMR, FTIR and XRD. Essential for drug delivery applications, SEC were shown to be non-toxic to human endothelial cells and free of allergenic protein epitopes by MALDI-TOF-MS and ESI-QqToF-MS. Potential application for targeted release into the intestinal region of the gastrointestinal tract (GIT) was demonstrated by 88 ± 1% of the drug being retained in simulated gastric fluid (SGF) after 45 minutes and 85 ± 2% being released after 5 min in buffer (PBS; pH 7.4). The SEC were shown to provide significant taste masking of encapsulated ibuprofen in a double blind trial with 10 human volunteers.
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Diego-Taboada A, Cousson P, Raynaud E, Huang Y, Lorch M, Binks BP, Queneau Y, Boa AN, Atkin SL, Beckett ST, Mackenzie G. Sequestration of edible oil from emulsions using new single and double layered microcapsules from plant spores. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm00103a] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Fambrini M, Michelotti V, Pugliesi C. Orange, yellow and white-cream: inheritance of carotenoid-based colour in sunflower pollen. PLANT BIOLOGY (STUTTGART, GERMANY) 2010; 12:197-205. [PMID: 20653902 DOI: 10.1111/j.1438-8677.2009.00205.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Inheritance of pollen colour was studied in sunflower (Helianthus annuus L.) using three distinct pollen colour morphs: orange, yellow and white-cream. Orange is the most common colour of sunflower pollen, while the yellow morph is less frequent. These two types were observed in the inbred lines F11 and EF2L, respectively. White-cream pollen is a rare phenotype in nature, and was identified in a mutant, named white-cream pollen, recovered in the R(2) generation of an in vitro regenerated plant. The F11 inbred line was used as starting material for in vitro regeneration. The carotenoid content of these three pollen morphs differed, and was extremely reduced in white-cream pollen. The phenotype of F(1) populations obtained by reciprocal crosses revealed that the orange trait was dominant over both white-cream and yellow. Segregation of F(2) populations of both crosses, orange x yellow and orange x white-cream, approached a 3:1 ratio, indicating the possibility of simple genetic control. By contrast, a complementation cross between the two lines with white-cream and yellow pollen produced F(1) plants with orange pollen. The F(2) populations of this cross-segregated as nine orange: four white-cream: four yellow. A model conforming to the involvement of two unlinked genes, here designated Y and O, can explain these results. Accessions with yellow pollen would have the genotype YYoo, the white-cream pollen mutant would have yyOO and the accession with orange pollen would have YYOO. Within F(2) populations of the cross white-cream x yellow a new genotype, yyoo, with white-cream pollen was scored. The results of the cross yyoo x YYoo produced only F(1) plants with yellow pollen, supporting a recessive epistatic model of inheritance between two loci. In this model, yy is epistatic on O and o. In F(2) populations, the distributions of phenotypic classes suggested that the genetic control of carotenoid content is governed by major genes, with large effects segregating in a background of polygenic variation. These three pollen morphs can provide insight into the sequence in which genes act, as well into the biochemical pathway controlling carotenoid biosynthesis in anthers and the transfer of these different pigments into pollenkitt.
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Affiliation(s)
- M Fambrini
- Dipartimento di Biologia delle Piante Agrarie Sezione di Genetica, Università di Pisa, Pisa, Italy
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27
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Pollen-imprinted polyurethanes for QCM allergen sensors. Anal Bioanal Chem 2009; 394:523-8. [DOI: 10.1007/s00216-009-2718-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Revised: 02/16/2009] [Accepted: 02/17/2009] [Indexed: 10/21/2022]
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28
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Kang SH, Joo HM, Park SI, Jung WS, Hong SS, Seo KW, Jeon MS, Choi HG, Kim HJ. Cryobiological Perspectives on the Cold Adaptation of Polar Organisms. ACTA ACUST UNITED AC 2007. [DOI: 10.4217/opr.2007.29.3.263] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Skirycz A, Jozefczuk S, Stobiecki M, Muth D, Zanor MI, Witt I, Mueller-Roeber B. Transcription factor AtDOF4;2 affects phenylpropanoid metabolism in Arabidopsis thaliana. THE NEW PHYTOLOGIST 2007; 175:425-438. [PMID: 17635218 DOI: 10.1111/j.1469-8137.2007.02129.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
In a phenotypic screen of plants constitutively overexpressing DOF (DNA-binding-with-one-finger) transcription factors under the control of the Cauliflower mosaic virus 35S promoter, AtDOF4;2 was identified as a gene inducing a bushy plant phenotype and potentially being involved in the regulation of phenylpropanoid metabolism in Arabidopsis. Further molecular and biochemical characterization was performed in parallel using transgenic plants with enhanced and reduced AtDOF4;2 expression. The expression pattern of AtDOF4;2 was determined by quantitative real-time polymerase chain reaction (Q-RTPCR) and through promoter-beta-glucuronidase (GUS) fusions, indicating preferential transcriptional activity in axillary buds of the flower stalk, the hypocotyls periderm and in tapetum cells. Constitutive overexpression and RNAi-mediated silencing of AtDOF4;2 caused reciprocal changes in the expression of flavonoid biosynthetic genes and the accumulation of flavonoids under cold and high-light conditions. Moreover, tapetum-specific overexpression of AtDOF4;2 led to pollen grains devoid of flavonols. In contrast to its negative influence on flavonoid biosynthesis and coincident with high expression in the periderm and tapetum, AtDOF4;2 positively influences the production of hydroxycinnamic acids in the hypocotyl and flower buds, implicating its possible importance for suberin and sporopollenin production. These data provide evidence that AtDOF4;2, influences phenylpropanoid metabolism in an environmental and tissue-specific manner.
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Affiliation(s)
- Aleksandra Skirycz
- Max-Planck Institute of Molecular Plant Physiology, Cooperative Research Group, Am Mühlenberg 1, D-14476 Potsdam, Germany
- University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
| | - Szymon Jozefczuk
- Max-Planck Institute of Molecular Plant Physiology, Cooperative Research Group, Am Mühlenberg 1, D-14476 Potsdam, Germany
| | - Maciej Stobiecki
- Institute of Bioorganic Chemistry PAS, Noskowskiego 12/14, 61-704 Poznań, Poland
| | - Dorota Muth
- Institute of Bioorganic Chemistry PAS, Noskowskiego 12/14, 61-704 Poznań, Poland
| | - Maria Inés Zanor
- Max-Planck Institute of Molecular Plant Physiology, Cooperative Research Group, Am Mühlenberg 1, D-14476 Potsdam, Germany
| | - Isabell Witt
- Max-Planck Institute of Molecular Plant Physiology, Cooperative Research Group, Am Mühlenberg 1, D-14476 Potsdam, Germany
- University of Cologne Zülpicher Straße 47 D-50674 Cologne, Germany
| | - Bernd Mueller-Roeber
- Max-Planck Institute of Molecular Plant Physiology, Cooperative Research Group, Am Mühlenberg 1, D-14476 Potsdam, Germany
- University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
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Markle DF, Clauson K. ONTOGENETIC AND HABITAT-RELATED CHANGES IN DIET OF LATE LARVAL AND JUVENILE SUCKERS (CATOSTOMIDAE) IN UPPER KLAMATH LAKE, OREGON. WEST N AM NATURALIST 2006. [DOI: 10.3398/1527-0904(2006)66[492:oahcid]2.0.co;2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Wang SB, Chen F, Sommerfeld M, Hu Q. Isolation and proteomic alalysis of cell wall-deficientHaematococcus pluvialis mutants. Proteomics 2005; 5:4839-51. [PMID: 16281177 DOI: 10.1002/pmic.200400092] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The green alga Haematococcus pluvialis has a plant-like cell wall consisting of glycoproteins and cellulose that is modified during the cell cycle and under various conditions. These features allow Haematococcus to be used as a model organism for studying cell wall biology. Development of the Haematococcus model is hampered by the absence of mutants that could provide insight into the biosynthesis and assembly of wall components. Haematococcus mutants (WM#537 and WM#2978) (WM--wall mutant) with defective cell walls were obtained by chemical mutagenesis. WM#537 features a secondary wall of considerably reduced thickness, whereas WM#2978 possesses a somewhat reduced secondary wall with little intervening space between the wall and plasmalemma. 2-DE revealed that a majority of the cell wall proteins were present in the wild-type and mutant cell walls throughout the cell cycle. PMF identified 55 wall protein orthologs from these strains, including a subset of induced proteins known to be involved in wall construction, remodeling, and defense. Down-regulation of certain wall proteins in the two mutants was associated with the wall defects, whereas overexpression of other proteins may have compensated for the defective walls in the two mutants.
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Affiliation(s)
- Sheng-Bing Wang
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
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BOHNE GUIDO, WOEHLECKE HOLGER, EHWALD RUDOLF. Water relations of the pine exine. ANNALS OF BOTANY 2005; 96:201-8. [PMID: 15897205 PMCID: PMC4246869 DOI: 10.1093/aob/mci169] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
BACKGROUND AND AIMS Water adhesion forces, water absorption capacity and permeability of the pine exine were investigated to consider a possible function of sporopollenin coatings in the control of water transport. METHODS The experiments were carried out with sporopollenin capsules obtained from pine pollen consisting of an empty central capsule and two sacci. Changes in the concentration of excluded dextran molecules in the medium were analysed to quantify water absorption by purified exine fragments and the osmotic volume flow out of the intact central capsule. KEY RESULTS The contact angle of sporopollenin to water is higher than the one to ethanol and lower than the one to n-heptane. The water-filled pore space in pine sporopollenin amounts to only 20.6 % of the matrix volume. A monosaccharide was excluded from 15 % and a trisaccharide from about 38 % of this space. Shrinkage of the central capsule induced by permeable osmotica was transient, whereas that induced by sodium polyacrylate (2100 g mol(-1)) was stable. Values obtained for the hydraulic conductance L(P) of the exine (0.39-0.48 microm s(-1) MPa(-1)) are comparable in size to those of biomembranes. Sodium sulfate solutions induced a significant osmotic flow through the exine (reflection coefficient at least 0.6). The exine around the central capsule can be ruptured by equilibration of its lumen with a concentrated electrolyte solution and subsequent transfer to water. The denatured protoplast along with the intact intine was ejected when pollen grains were subjected to this osmotic shock treatment. CONCLUSIONS The pine exine is easily wetted with water and does not represent a significant barrier to water exchange either liquid or gaseous. Through osmotic burst, it can be separated from the intine. The effect of salts and small solute molecules on water fluxes may be functionally significant for rehydration upon pollination.
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Affiliation(s)
- GUIDO BOHNE
- Institute of Biology, Humboldt-University Berlin, Invalidenstr. 42, 10115 Berlin, Germany
| | | | - RUDOLF EHWALD
- Institute of Biology, Humboldt-University Berlin, Invalidenstr. 42, 10115 Berlin, Germany
- For correspondence. E-mail
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Preston J, Wheeler J, Heazlewood J, Li SF, Parish RW. AtMYB32 is required for normal pollen development in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2004; 40:979-95. [PMID: 15584962 DOI: 10.1111/j.1365-313x.2004.02280.x] [Citation(s) in RCA: 204] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
AtMYB32 gene is a member of the R2R3 MYB gene family coding for transcription factors in Arabidopsis thaliana. Its expression pattern was analysed using Northern blotting, in situ hybridization and promoter-GUS fusions. AtMYB32 is expressed in many tissues, but most strongly in the anther tapetum, stigma papillae and lateral root primordia. AtMYB32-GUS was induced in leaves and stems following wounding, and in root primordia by auxin. T-DNA insertion populations were screened and two insertion mutants were identified, both of which were partially male sterile, more than 50% of the pollen grains being distorted in shape and lacking cytoplasm. AtMYB4 is closely related to AtMYB32 and represses the CINNAMATE 4-HYDROXYLASE gene. Distorted pollen grains were produced in both AtMYB4 insertion mutant and overexpression lines. In an AtMYB32 insertion mutant, the transcript levels of the DIHYDROFLAVONOL 4-REDUCTASE and ANTHOCYANIDIN SYNTHASE genes decreased while the level of the CAFFEIC ACID 0-METHYLTRANSFERASE transcript increased. Change in the levels of AtMYB32 and AtMYB4 expression may influence pollen development by changing the flux along the phenylpropanoid pathways, affecting the composition of the pollen wall.
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Affiliation(s)
- Jeremy Preston
- Botany Department, School of Life Sciences, La Trobe University, Bundoora, Victoria 3083, Australia
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Costa MA, Collins RE, Anterola AM, Cochrane FC, Davin LB, Lewis NG. An in silico assessment of gene function and organization of the phenylpropanoid pathway metabolic networks in Arabidopsis thaliana and limitations thereof. PHYTOCHEMISTRY 2003; 64:1097-112. [PMID: 14568076 DOI: 10.1016/s0031-9422(03)00517-x] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The Arabidopsis genome sequencing in 2000 gave to science the first blueprint of a vascular plant. Its successful completion also prompted the US National Science Foundation to launch the Arabidopsis 2010 initiative, the goal of which is to identify the function of each gene by 2010. In this study, an exhaustive analysis of The Institute for Genomic Research (TIGR) and The Arabidopsis Information Resource (TAIR) databases, together with all currently compiled EST sequence data, was carried out in order to determine to what extent the various metabolic networks from phenylalanine ammonia lyase (PAL) to the monolignols were organized and/or could be predicted. In these databases, there are some 65 genes which have been annotated as encoding putative enzymatic steps in monolignol biosynthesis, although many of them have only very low homology to monolignol pathway genes of known function in other plant systems. Our detailed analysis revealed that presently only 13 genes (two PALs, a cinnamate-4-hydroxylase, a p-coumarate-3-hydroxylase, a ferulate-5-hydroxylase, three 4-coumarate-CoA ligases, a cinnamic acid O-methyl transferase, two cinnamoyl-CoA reductases) and two cinnamyl alcohol dehydrogenases can be classified as having a bona fide (definitive) function; the remaining 52 genes currently have undetermined physiological roles. The EST database entries for this particular set of genes also provided little new insight into how the monolignol pathway was organized in the different tissues and organs, this being perhaps a consequence of both limitations in how tissue samples were collected and in the incomplete nature of the EST collections. This analysis thus underscores the fact that even with genomic sequencing, presumed to provide the entire suite of putative genes in the monolignol-forming pathway, a very large effort needs to be conducted to establish actual catalytic roles (including enzyme versatility), as well as the physiological function(s) for each member of the (multi)gene families present and the metabolic networks that are operative. Additionally, one key to identifying physiological functions for many of these (and other) unknown genes, and their corresponding metabolic networks, awaits the development of technologies to comprehensively study molecular processes at the single cell level in particular tissues and organs, in order to establish the actual metabolic context.
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Affiliation(s)
- Michael A Costa
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, USA
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Wang A, Xia Q, Xie W, Dumonceaux T, Zou J, Datla R, Selvaraj G. Male gametophyte development in bread wheat (Triticum aestivum L.): molecular, cellular, and biochemical analyses of a sporophytic contribution to pollen wall ontogeny. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2002; 30:613-23. [PMID: 12061894 DOI: 10.1046/j.1365-313x.2002.01313.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Bread wheat (hexaploid AABBDD genome; 16 billion basepairs) is a genetically complex, self-pollinating plant with bisexual flowers that produce short-lived pollen. Very little is known about the molecular biology of its gametophyte development despite a longstanding interest in hybrid seeds. We present here a comprehensive characterization of three apparently homeologous genes (TAA1a, TAA1b and TAA1c) and demonstrate their anther-specific biochemical function. These eight-exon genes, found at only one copy per haploid complement in this large genome, express specifically within the sporophytic tapetum cells. The presence of TAA1 mRNA and protein was evident only at specific stages of pollen development as the microspore wall thickened during the progression of free microspores into vacuolated-microspores. This temporal regulation matched the assembly of wall-impregnated sporopollenin, a phenylpropanoid-lipid polymer containing very long chain fatty alcohols (VLCFAlc), described in the literature. Our results establish that sporophytic genes contribute to the production of fatty alcohols: Transgenic expression of TAA1 afforded production of long/VLCFAlc in tobacco seeds (18 : 1; 20 : 1; 22 : 1; 24 : 0; 26 : 0) and in Escherichia coli (14 : 0; 16 : 0; 18 : 1), suggesting biochemical versatility of TAA1 with respect to cellular milieu and substrate spectrum. Pollen walls additionally contain fatty alcohols in the form of wax esters and other lipids, and some of these lipids are known to play a role in the highly specific sexual interactions at the pollen-pistil interface. This study provides a handle to study these and to manipulate pollen traits, and, furthermore, to understand the molecular biology of fatty alcohol metabolism in general.
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Affiliation(s)
- Aiming Wang
- Plant Biotechnology Institute, National Research Council of Canada, 110 Gymnasium Place, Saskatoon, Saskatchewan, Canada S7N 0W9
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Pacini E. Tapetum character states: analytical keys for tapetum types and activities. ACTA ACUST UNITED AC 1997. [DOI: 10.1139/b97-859] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The different types of tapetum found in the spermatophyta are described, along with associated characters. The characters (taken singly, pairwise, or in multiple combinations) are (i) tapetum types; (ii) cell walls, tapetum types, and loculus; (iii) tapetal cells individually, tapetum types, and loculus; (iv) number of pollen grains enveloped by tapetal cells and type of pollen dispersing unit; (v) cell types and tapetum types; (vi) number of nuclei per cell and tapetum type; (vii) cycles of hyperactivity; (viii) exine formation; (ix) orbicles; (x) peritapetal membrane; (xi) plastid differentiation; (xii) stage of pollen development in which tapetal cells degenerate and type of pollen coat; (xiii) storage vacuoles; (xiv) sporophytic proteins; and (xv) devices of tapetal origin responsible for compound pollen formation and pollination. Examples are given and an analytical key of structural and functional diversity is provided as a helpful approach to the study of the tapetum. Key words: tapetum types, activities, pollen dispersing units.
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Taylor LP, Hepler PK. POLLEN GERMINATION AND TUBE GROWTH. ANNUAL REVIEW OF PLANT PHYSIOLOGY AND PLANT MOLECULAR BIOLOGY 1997; 48:461-491. [PMID: 15012271 DOI: 10.1146/annurev.arplant.48.1.461] [Citation(s) in RCA: 386] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Many aspects of Angiosperm pollen germination and tube growth are discussed including mechanisms of dehydration and rehydration, in vitro germination, pollen coat compounds, the dynamic involvement of cytoskeletal elements (actin, microtubules), calcium ion fluxes, extracellular matrix elements (stylar arabinogalactan proteins), and control mechanisms of gene expression in dehydrating and germinating pollen. We focus on the recent developments in pollen biology that help us understand how the male gamete survives and accomplishes its successful delivery to the ovule of the sperm to effect sexual reproduction.
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Affiliation(s)
- Loverine P. Taylor
- Department of Genetics and Cell Biology, Washington State University, Pullman, Washington 99164-4234, Biology Department, University of Massachusetts, Amherst, Massachusetts 01003
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