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Izumi H, Nakai Y, Uji T, Nagaosa K, Fukuda S, Mizuta H, Saga N. Isolation and characterization of a spore development mutant in Pyropia yezoensis (Rhodophyta) induced via insertional mutagenesis. JOURNAL OF PHYCOLOGY 2025. [PMID: 40323712 DOI: 10.1111/jpy.70026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2024] [Revised: 04/14/2025] [Accepted: 04/15/2025] [Indexed: 05/07/2025]
Abstract
Mechanistic elucidation of spore development is essential for understanding reproductive strategies and improving seaweed cultivation. In this study, we isolated a mutant with spore development defects in Pyropia yezoensis (Rhodophyta) from among genetic transformants generated via insertional mutagenesis. We characterized the mutant phenotype and identified the genomic region containing the mutation. The mutant produced spores (archeospores, zygotospores, and conchospores) at every relevant stage of the life history. No evident differences were observed in the appearance of the released spores at any stage under light microscopy between the wild-type and mutant strains; however, the mutant exhibited a trend of reduced spore release compared with the wild-type. Additionally, the archeospores released by the mutant remained round after being released from the sporangium, failed to adhere to the substratum, did not germinate, and showed no cell wall development after 4 days of standard culture, in contrast to the wild-type. Similar results were observed for the zygotospores and conchospores. These findings indicate that the main characteristic of this mutant was poor spore release, and the released spores failed to germinate. Whole-genome sequencing revealed the introduction of exogenous DNA into the nuclear genome of the mutant and suggested the presence of duplications, deletion, and inversion in the mutant genome. Notably, a deletion of approximately 13 kb was detected in the mutant genome flanking the insertion, and this region contained a plant homeodomain, suggesting that homeodomain-containing proteins may regulate spore development in P. yezoensis.
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Affiliation(s)
- Hikari Izumi
- Section of Food Sciences, Institute of Regional Innovation, Hirosaki University, Aomori, Aomori, Japan
| | - Yuji Nakai
- Section of Food Sciences, Institute of Regional Innovation, Hirosaki University, Aomori, Aomori, Japan
| | - Toshiki Uji
- Division of Marine Life Science, Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido, Japan
| | - Kaz Nagaosa
- Section of Food Sciences, Institute of Regional Innovation, Hirosaki University, Aomori, Aomori, Japan
| | - Satoru Fukuda
- Regional Fisheries Co-Creation Center, Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido, Japan
| | - Hiroyuki Mizuta
- Division of Marine Life Science, Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido, Japan
| | - Naotsune Saga
- Section of Food Sciences, Institute of Regional Innovation, Hirosaki University, Aomori, Aomori, Japan
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Li Y, Yang J, Sun Z, Niu J, Wang G. Overexpression of MPV17/PMP22-like protein 2 gene decreases production of radical oxygen species in Pyropia yezoensis (Bangiales, Rhodophyta). JOURNAL OF PHYCOLOGY 2024; 60:928-941. [PMID: 38924097 DOI: 10.1111/jpy.13474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Revised: 04/16/2024] [Accepted: 05/14/2024] [Indexed: 06/28/2024]
Abstract
The northward shift of Pyropia yezoensis aquaculture required the breeding of germplasms with tolerance to the oxidative stress due to the high light conditions of the North Yellow Sea area. The MPV17/PMP22 family proteins were identified as a molecule related to reactive oxygen species (ROS) metabolism. Here, one of the MPV17 homolog genes designated as PyM-LP2 was selected for functional identification by introducing the encoding sequence region/reverse complementary fragment into the Py. yezoensis genome. Although the photosynthetic activity, the respiratory rate, and the ROS level in wild type (WT) and different gene-transformed algal strains showed similar levels under normal conditions, the overexpression (OE) strain exhibited higher values of photosynthesis, respiration, and reducing equivalents pool size but lower intracellular ROS production under stress conditions compared with the WT. Conversely, all the above parameters showed opposite variation trends in RNAi strain as those in the OE strain. This implied that the PyM-LP2 protein was involved in the mitigation of the oxidative stress. Sequence analysis revealed that this PyM-LP2 protein was assorted to peroxisomes and might serve as a poring channel for transferring malate (Mal) to peroxisomes. By overexpressing PyM-LP2, the transfer of Mal from chloroplasts to peroxisomes was enhanced under stress conditions, which promoted photorespiration and ultimately alleviated excessive reduction of the photosynthetic electron chain. This research lays the groundwork for the breeding of algae with enhanced resistance to oxidative stresses.
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Affiliation(s)
- Yujie Li
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, China
| | - Jiali Yang
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, China
| | - Zhenjie Sun
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
| | - Jianfeng Niu
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
| | - Guangce Wang
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Chinese Academy of Sciences, Qingdao, China
- University of Chinese Academy of Sciences, Beijing, China
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Mikami K, Takahashi M. Life cycle and reproduction dynamics of Bangiales in response to environmental stresses. Semin Cell Dev Biol 2023; 134:14-26. [PMID: 35428563 DOI: 10.1016/j.semcdb.2022.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 04/05/2022] [Accepted: 04/06/2022] [Indexed: 12/16/2022]
Abstract
Red algae of the order Bangiales are notable for exhibiting flexible promotion of sexual and asexual reproductive processes by environmental stresses. This flexibility indicates that a trade-off between vegetative growth and reproduction occurs in response to environmental stresses that influence the timing of phase transition within the life cycle. Despite their high phylogenetic divergence, both filamentous and foliose red alga in the order Bangiales exhibit a haploid-diploid life cycle, with a haploid leafy or filamentous gametophyte (thallus) and a diploid filamentous sporophyte (conchocelis). Unlike haploid-diploid life cycles in other orders, the gametophyte in Bangiales is generated independently of meiosis; the regulation of this generation transition is not fully understood. Based on transcriptome and gene expression analyses, the originally proposed biphasic model for alternation of generations in Bangiales was recently updated to include a third stage. Along with the haploid gametophyte and diploid sporophyte, the triphasic framework recognizes a diploid conchosporophyte-a conchosporangium generated on the conchocelis-phase and previously considered to be part of the sporophyte. In addition to this sexual life cycle, some Bangiales species have an asexual life cycle in which vegetative cells of the thallus develop into haploid asexual spores, which are then released from the thallus to produce clonal thalli. Here, we summarize the current knowledge of the triphasic life cycle and life cycle trade-off in Neopyropia yezoensis and 'Bangia' sp. as model organisms for the Bangiales.
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Affiliation(s)
- Koji Mikami
- Department of Integrative Studies of Plant and Animal Production, School of Food Industrial Sciences, Miyagi University, Sendai, Japan.
| | - Megumu Takahashi
- Department of Ocean and Fisheries Sciences, Faculty of Bio-Industry, Tokyo University of Agriculture, Abashiri, Japan
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Guan X, Mao Y, Stiller JW, Shu S, Pang Y, Qu W, Zhang Z, Tang F, Qian H, Chen R, Sun B, Guoying D, Mo Z, Kong F, Tang X, Wang D. Comparative Gene Expression and Physiological Analyses Reveal Molecular Mechanisms in Wound-Induced Spore Formation in the Edible Seaweed Nori. FRONTIERS IN PLANT SCIENCE 2022; 13:840439. [PMID: 35371140 PMCID: PMC8969420 DOI: 10.3389/fpls.2022.840439] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 02/24/2022] [Indexed: 05/27/2023]
Abstract
Genetic reprogramming of differentiated cells is studied broadly in multicellular Viridiplantae as an adaptation to herbivory or damage; however, mechanisms underlying cell development and redifferentiation are largely unknown in red algae, their nearest multicellular relatives. Here we investgate cell reprogramming in the widely cultivated, edible seaweed Neopyropia yezoesis ("nori"), where vegetative cells in wounded blades differentiate and release as large numbers of asexual spores. Based upon physiological changes and transcriptomic dynamics after wound stress in N. yezoensis and its congener Neoporphyra haitanensis, another cultivar that does not differentiate spores after wounding, we propose a three-phase model of wound-induced spore development in N. yezoensis. In Phase I, propagation of ROS by RBOH and SOD elicites systematic transduction of the wound signal, while Ca2+ dependent signaling induces cell reprogramming. In Phase II, a TOR signaling pathway and regulation of cyclin and CDK genes result in cell divisions that spread inward from the wound edge. Once sporangia form, Phase III involves expression of proteins required for spore maturation and cell wall softening. Our analyses not only provide the first model for core molecular processes controlling cellular reprogramming in rhodophytes, but also have practical implications for achieving greater control over seeding in commercial nori farming.
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Affiliation(s)
- Xiaowei Guan
- Key Laboratory of Marine Genetics and Breeding (OUC), Ministry of Education, Qingdao, China
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Yunxiang Mao
- Key Laboratory of Marine Genetics and Breeding (OUC), Ministry of Education, Qingdao, China
- Key Laboratory of Utilization and Conservation for Tropical Marine Bioresources (Hainan Tropical Ocean University), Ministry of Education, Sanya, China
| | - John W. Stiller
- Department of Biology, East Carolina University, Greenville, NC, United States
| | - Shanshan Shu
- Key Laboratory of Marine Genetics and Breeding (OUC), Ministry of Education, Qingdao, China
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Ying Pang
- Key Laboratory of Marine Genetics and Breeding (OUC), Ministry of Education, Qingdao, China
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Weihua Qu
- Key Laboratory of Marine Genetics and Breeding (OUC), Ministry of Education, Qingdao, China
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Zehao Zhang
- Key Laboratory of Marine Genetics and Breeding (OUC), Ministry of Education, Qingdao, China
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Fugeng Tang
- Key Laboratory of Marine Genetics and Breeding (OUC), Ministry of Education, Qingdao, China
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Huijuan Qian
- Key Laboratory of Marine Genetics and Breeding (OUC), Ministry of Education, Qingdao, China
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Rui Chen
- Key Laboratory of Marine Genetics and Breeding (OUC), Ministry of Education, Qingdao, China
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Bin Sun
- Key Laboratory of Marine Genetics and Breeding (OUC), Ministry of Education, Qingdao, China
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Du Guoying
- Key Laboratory of Marine Genetics and Breeding (OUC), Ministry of Education, Qingdao, China
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Zhaolan Mo
- Key Laboratory of Marine Genetics and Breeding (OUC), Ministry of Education, Qingdao, China
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Fanna Kong
- Key Laboratory of Marine Genetics and Breeding (OUC), Ministry of Education, Qingdao, China
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Xianghai Tang
- Key Laboratory of Marine Genetics and Breeding (OUC), Ministry of Education, Qingdao, China
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Dongmei Wang
- Key Laboratory of Marine Genetics and Breeding (OUC), Ministry of Education, Qingdao, China
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
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