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Koyamatsu D, Otsubo M, Ohira T, Sato MP, Suzuki-Masuko H, Shiota T, Takenaka Takano K, Ozeki M, Otsuka K, Ogura Y, Hayashi T, Watanabe M, Inaba T, Ito-Inaba Y. Molecular characterization of SrSTP14, a sugar transporter from thermogenic skunk cabbage, and its possible role in developing pollen. Physiol Plant 2023; 175:e13957. [PMID: 37338180 DOI: 10.1111/ppl.13957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 06/13/2023] [Accepted: 06/15/2023] [Indexed: 06/21/2023]
Abstract
In floral thermogenesis, sugars play an important role not only as energy providers but also as growth and development facilitators. Yet, the mechanisms underlying sugar translocation and transport in thermogenic plants remain to be studied. Asian skunk cabbage (Symplocarpus renifolius) is a species that can produce durable and intense heat in its reproductive organ, the spadix. Significant morphological and developmental changes in the stamen are well-characterized in this plant. In this study, we focused on the sugar transporters (STPs), SrSTP1 and SrSTP14, whose genes were identified by RNA-seq as the upregulated STPs during thermogenesis. Real-time PCR confirmed that mRNA expression of both STP genes was increased from the pre-thermogenic to the thermogenic stage in the spadix, where it is predominantly expressed in the stamen. SrSTP1 and SrSTP14 complemented the growth defects of a hexose transporter-deficient yeast strain, EBY4000, on media containing 0.02, 0.2, and 2% (w/v) glucose and galactose. Using a recently developed transient expression system in skunk cabbage leaf protoplasts, we revealed that SrSTP1 and SrSTP14-GFP fusion proteins were mainly localized to the plasma membrane. To dig further into the functional analysis of SrSTPs, tissue-specific localization of SrSTPs was investigated by in situ hybridization. Using probes for SrSTP14, mRNA expression was observed in the microspores within the developing anther at the thermogenic female stage. These results indicate that SrSTP1 and SrSTP14 transport hexoses (e.g., glucose and galactose) at the plasma membrane and suggest that SrSTP14 may play a role in pollen development through the uptake of hexoses into pollen precursor cells.
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Affiliation(s)
- Daiki Koyamatsu
- Department of Agricultural and Environmental Sciences, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan
| | - Miyabi Otsubo
- Department of Agricultural and Environmental Sciences, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan
| | - Tomonori Ohira
- Department of Agricultural and Environmental Sciences, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan
| | - Mitsuhiko P Sato
- Department of Frontier Research and Development, Kazusa DNA Research Institute, Kisarazu, Japan
| | | | - Takuya Shiota
- Organization for Promotion of Tenure Track, University of Miyazaki, Miyazaki, Japan
- Frontier Science Research Center, University of Miyazaki, Miyazaki, Japan
| | - Kohei Takenaka Takano
- Natural Environment Division, Nagano Environmental Conservation Research Institute, Nagano, Japan
| | - Masaaki Ozeki
- Natural Environment Division, Nagano Environmental Conservation Research Institute, Nagano, Japan
| | - Koichi Otsuka
- Natural Environment Division, Nagano Environmental Conservation Research Institute, Nagano, Japan
| | - Yoshitoshi Ogura
- Division of Microbiology, Department of Infectious Medicine, Kurume University School of Medicine, Fukuoka, Japan
| | - Tetsuya Hayashi
- Department of Bacteriology, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Masao Watanabe
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Takehito Inaba
- Department of Agricultural and Environmental Sciences, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan
| | - Yasuko Ito-Inaba
- Department of Agricultural and Environmental Sciences, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan
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Maekawa H, Otsubo M, Sato MP, Takahashi T, Mizoguchi K, Koyamatsu D, Inaba T, Ito-Inaba Y. Establishing an efficient protoplast transient expression system for investigation of floral thermogenesis in aroids. Plant Cell Rep 2022; 41:263-275. [PMID: 34704119 DOI: 10.1007/s00299-021-02806-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 10/15/2021] [Indexed: 06/13/2023]
Abstract
Floral thermogenesis is an important reproductive strategy for attracting pollinators. We developed essential biological tools for studying floral thermogenesis using two species of thermogenic aroids, Symplocarpus renifolius and Alocasia odora. Aroids contain many species with intense heat-producing abilities in their inflorescences. Several genes have been proposed to be involved in thermogenesis of these species, but biological tools for gene functional analyses are lacking. In this study, we aimed to develop a protoplast-based transient expression (PTE) system for the study of thermogenic aroids. Initially, we focused on skunk cabbage (Symplocarpus renifolius) because of its ability to produce intense as well as durable heat. In this plant, leaf protoplasts were isolated from potted and shoot tip-cultured plants with high efficiency (ca. 1.0 × 105/g fresh weight), and more than half of these protoplasts were successfully transfected. Using this PTE system, we determined the protein localization of three mitochondrial energy-dissipating proteins, SrAOX, SrUCPA, and SrNDA1, fused to green fluorescent protein (GFP). These three GFP-fused proteins were localized in MitoTracker-stained mitochondria in leaf protoplasts, although the green fluorescent particles in protoplasts expressing SrUCPA-GFP were significantly enlarged. Finally, to assess whether the PTE system established in the leaves of S. renifolius is applicable for floral tissues of thermogenic aroids, inflorescences of S. renifolius and another thermogenic aroid (Alocasia odora) were used. Although protoplasts were successfully isolated from several tissues of the inflorescences, PTE systems worked well only for the protoplasts isolated from the female parts (slightly thermogenic or nonthermogenic) of A. odora inflorescences. Our developed system has a potential to be widely used in inflorescences as well as leaves in thermogenic aroids and therefore may be a useful biological tool for investigating floral thermogenesis.
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Affiliation(s)
- Haruhiko Maekawa
- Department of Agricultural and Environmental Sciences, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuenkibanadai-nishi, Miyazaki, 889-2192, Japan
| | - Miyabi Otsubo
- Department of Agricultural and Environmental Sciences, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuenkibanadai-nishi, Miyazaki, 889-2192, Japan
| | - Mitsuhiko P Sato
- Department of Frontier Research and Development, Kazusa DNA Research Institute, 2-6-7 Kazusakamatari, Kisarazu, Chiba, 292-0818, Japan
| | - Tomoko Takahashi
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, Shimo-Okubo 255, Sakura-ku, Saitama, 338-8570, Japan
| | - Koichiro Mizoguchi
- Department of Agricultural and Environmental Sciences, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuenkibanadai-nishi, Miyazaki, 889-2192, Japan
| | - Daiki Koyamatsu
- Department of Agricultural and Environmental Sciences, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuenkibanadai-nishi, Miyazaki, 889-2192, Japan
| | - Takehito Inaba
- Department of Agricultural and Environmental Sciences, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuenkibanadai-nishi, Miyazaki, 889-2192, Japan
| | - Yasuko Ito-Inaba
- Department of Agricultural and Environmental Sciences, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuenkibanadai-nishi, Miyazaki, 889-2192, Japan.
- Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, 980-8577, Japan.
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