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Sato N, Khoa HV, Mikami K. Heat stress memory differentially regulates the expression of nitrogen transporter genes in the filamentous red alga ' Bangia' sp. ESS1. FRONTIERS IN PLANT SCIENCE 2024; 15:1331496. [PMID: 38375079 PMCID: PMC10875135 DOI: 10.3389/fpls.2024.1331496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 01/22/2024] [Indexed: 02/21/2024]
Abstract
Introduction To withstand high temperatures that would be lethal to a plant in the naïve state, land plants must establish heat stress memory. The acquisition of heat stress tolerance via heat stress memory in algae has only been observed in the red alga 'Bangia' sp. ESS1. Methods In this study, we further evaluated the intrinsic ability of this alga to establish heat stress memory by monitoring hydrogen peroxide (H2O2) production and examining the relationship between heat stress memory and the expression of genes encoding nitrogen transporters, since heat stress generally reduces nitrogen absorption. Next, genes encoding nitrogen transporters were selected from our unpublished transcriptome data of 'Bangia' sp. ESS1. Results We observed a reduction in H2O2 content when heat stress memory was established in the alga. In addition, six ammonium transporter genes, a single-copy nitrate transporter gene and two urea transporter genes were identified. Two of these nitrogen transporter genes were induced by heat stress but not by heat stress memory, two genes showed heat stress memory-dependent expression, and one gene was induced by both treatments. Heat stress memory therefore differentially regulated the expression of the nitrogen transporter genes by reducing heat stress-inducible gene expression and inducing heat stress memory-dependent gene expression. Discussion These findings point to the functional diversity of nitrogen transporter genes, which play different roles under various heat stress conditions. The characteristic effects of heat stress memory on the expression of individual nitrogen transporter genes might represent an indispensable strategy for reducing the threshold of sensitivity to recurrent high-temperature conditions and for maintaining nitrogen absorption under such conditions in 'Bangia' sp. ESS1.
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Affiliation(s)
- Natsumi Sato
- School of Food Industrial Sciences, Miyagi University, Sendai, Japan
| | - Ho Viet Khoa
- Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Japan
| | - Koji Mikami
- School of Food Industrial Sciences, Miyagi University, Sendai, Japan
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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: 4.0] [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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LjAMT2;2 Promotes Ammonium Nitrogen Transport during Arbuscular Mycorrhizal Fungi Symbiosis in Lotus japonicus. Int J Mol Sci 2022; 23:ijms23179522. [PMID: 36076919 PMCID: PMC9455674 DOI: 10.3390/ijms23179522] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 08/19/2022] [Accepted: 08/19/2022] [Indexed: 11/18/2022] Open
Abstract
Arbuscular mycorrhizal fungi (AMF) are important symbiotic microorganisms in soil that engage in symbiotic relationships with legumes, resulting in mycorrhizal symbiosis. Establishment of strong symbiotic relationships between AMF and legumes promotes the absorption of nitrogen by plants. Ammonium nitrogen can be directly utilised by plants following ammonium transport, but there are few reports on ammonium transporters (AMTs) promoting ammonium nitrogen transport during AM symbiosis. Lotus japonicus is a typical legume model plant that hosts AMF. In this study, we analysed the characteristics of the Lotus japonicus ammonium transporter LjAMT2;2, and found that it is a typical ammonium transporter with mycorrhizal-induced and ammonium nitrogen transport-related cis-acting elements in its promoter region. LjAMT2;2 facilitated ammonium transfer in yeast mutant supplement experiments. In the presence of different nitrogen concentrations, the LjAMT2;2 gene was significantly upregulated following inoculation with AMF, and induced by low nitrogen. Overexpression of LjAMT2;2 increased the absorption of ammonium nitrogen, resulting in doubling of nitrogen content in leaves and roots, thus alleviating nitrogen stress and promoting plant growth.
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Wang J, Tang X, Mo Z, Mao Y. Metagenome-Assembled Genomes From Pyropia haitanensis Microbiome Provide Insights Into the Potential Metabolic Functions to the Seaweed. Front Microbiol 2022; 13:857901. [PMID: 35401438 PMCID: PMC8984609 DOI: 10.3389/fmicb.2022.857901] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 02/28/2022] [Indexed: 12/24/2022] Open
Abstract
Pyropia is an economically important edible red alga worldwide. The aquaculture industry and Pyropia production have grown considerably in recent decades. Microbial communities inhabit the algal surface and produce a variety of compounds that can influence host adaptation. Previous studies on the Pyropia microbiome were focused on the microbial components or the function of specific microbial lineages, which frequently exclude metabolic information and contained only a small fraction of the overall community. Here, we performed a genome-centric analysis to study the metabolic potential of the Pyropia haitanensis phycosphere bacteria. We reconstructed 202 unique metagenome-assembled genomes (MAGs) comprising all major taxa present within the P. haitanensis microbiome. The addition of MAGs to the genome tree containing all publicly available Pyropia-associated microorganisms increased the phylogenetic diversity by 50% within the bacteria. Metabolic reconstruction of the MAGs showed functional redundancy across taxa for pathways including nitrate reduction, taurine metabolism, organophosphorus, and 1-aminocyclopropane-1-carboxylate degradation, auxin, and vitamin B12 synthesis. Some microbial functions, such as auxin and vitamin B12 synthesis, that were previously assigned to a few Pyropia-associated microorganisms were distributed across the diverse epiphytic taxa. Other metabolic pathways, such as ammonia oxidation, denitrification, and sulfide oxidation, were confined to specific keystone taxa.
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Affiliation(s)
- Junhao Wang
- Key Laboratory of Marine Genetics and Breeding (Ministry of Education), College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Xianghai Tang
- Key Laboratory of Marine Genetics and Breeding (Ministry of Education), College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Zhaolan Mo
- Key Laboratory of Marine Genetics and Breeding (Ministry of Education), College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Key Laboratory of Tropical Aquatic Germplasm of Hainan Province, Sanya Oceanographic Institution, Ocean University of China, Sanya, China
| | - Yunxiang Mao
- Key Laboratory of Utilization and Conservation of Tropical Marine Bioresource (Ministry of Education), College of Fisheries and Life Sciences, Hainan Tropical Ocean University, Sanya, China
- Yazhou Bay Innovation Research Institute, Hainan Tropical Ocean University, Sanya, China
- Key Laboratory for Conservation and Utilization of Tropical Marine Fishery Resources of Hainan Province, Hainan Tropical Ocean University, Sanya, China
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Takahashi M, Kumari P, Li C, Mikami K. Low temperature causes discoloration by repressing growth and nitrogen transporter gene expression in the edible red alga Pyropia yezoensis. MARINE ENVIRONMENTAL RESEARCH 2020; 159:105004. [PMID: 32662437 DOI: 10.1016/j.marenvres.2020.105004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 04/25/2020] [Accepted: 04/26/2020] [Indexed: 06/11/2023]
Abstract
The reduced availability of nitrogen sources in seawater leads to discoloration of the edible red seaweed Pyropia yezoensis and induces the expression of genes encoding ammonium, nitrate and urea transporters. In the present study, we demonstrate that low temperatures can also cause discoloration of this economically important seaweed. Thus, we addressed regulatory mechanisms of cold-inducible discoloration. When P. yezoensis thalli were incubated at 0, 5 and 10°C, the thalli exhibited retarded growth and discoloration, along with reduced phycoerythrin contents. Fertilization with nitrogen sources did not recover this discoloration at 0°C, suggesting that defects in nitrogen absorption cause low temperature-induced discoloration. The expression levels of many nitrogen transporter genes were reduced at low temperature. We propose that low temperature-mediated repression of ammonium, nitrate and urea transporter gene expression promotes the reduced absorption of nitrogen sources in P. yezoensis, thereby leading to discoloration. This process is different from the well-known mechanism underlying discoloration in P. yezoensis under nitrogen-deficient conditions at normal culture temperature.
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Affiliation(s)
- Megumu Takahashi
- Faculty of Bio-Industry, Tokyo University of Agriculture, 196 Yasaka, Abashiri, 099-2493, Japan
| | - Puja Kumari
- Faculty of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate, 041-0821, Japan
| | - Chengze Li
- Graduate School of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate, 041-0821, Japan
| | - Koji Mikami
- Faculty of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate, 041-0821, Japan.
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Mikami K, Li C, Irie R, Hama Y. A unique life cycle transition in the red seaweed Pyropia yezoensis depends on apospory. Commun Biol 2019; 2:299. [PMID: 31396579 PMCID: PMC6685973 DOI: 10.1038/s42003-019-0549-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 07/16/2019] [Indexed: 01/27/2023] Open
Abstract
Plant life cycles consist of two temporally separated stages: a haploid gametophyte and a diploid sporophyte. In plants employing a haploid-diploid sexual life cycle, the transition from sporophyte to gametophyte generally depends on meiosis. However, previous work has shown that in the red seaweed Pyropia yezoensis, this transition is independent of meiosis, though how and when it occurs is unknown. Here, we explored this question using transcriptomic profiling of P. yezoensis gametophytes, sporophytes, and conchosporangia parasitically produced on sporophytes. We identify a knotted-like homeobox gene that is predominately expressed in the conchosporangium and may determine its identity. We also find that spore-like single cells isolated from the conchosporangium develop directly into gametophytes, indicating that the gametophyte identity is established before the release of conchospores and prior to the onset of meiosis. Based on our findings, we propose a triphasic life cycle for P. yezoensis involving production of gametophytes by apospory.
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Affiliation(s)
- Koji Mikami
- Faculty of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate, 041-8611 Japan
| | - Chengze Li
- Graduate School of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate, 041-8611 Japan
| | - Ryunosuke Irie
- Graduate School of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate, 041-8611 Japan
| | - Yoichiro Hama
- Faculty of Agriculture, Saga University, 1 Honjo, Saga, 840-8502 Japan
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Sasuga K, Yamanashi T, Nakayama S, Ono S, Mikami K. Discolored Red Seaweed Pyropia yezoensis with Low Commercial Value Is a Novel Resource for Production of Agar Polysaccharides. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2018; 20:520-530. [PMID: 29696549 DOI: 10.1007/s10126-018-9823-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 04/03/2018] [Indexed: 06/08/2023]
Abstract
The red seaweed Pyropia yezoensis has been demonstrated to be a novel resource for the production of high-quality agar. P. yezoensis is grown for the food industry in large-scale Japanese mariculture operations. However, discolored P. yezoensis is mostly discarded as an industrial waste, although it has some kind of utility values. Here, we evaluated the utility of discolored P. yezoensis as a resource for agar production. The quality of agar from the discolored seaweed was comparable to that from normal seaweed. In addition, as a distinguishing characteristic, agar yield was higher from discolored seaweeds than from normal types. Moreover, we successfully used agar from discolored P. yezoensis for bacterial plate media and DNA electrophoresis gels without agarose purification. Thus, our results demonstrate that discolored P. yezoensis is suitable for agar production and use in life science research. Diverting discolored P. yezoensis from disposal to agar production provides a solution to the current industrial waste problem in mariculture, as well as a secure source of agar for research purposes.
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Affiliation(s)
- Keiji Sasuga
- Graduate School of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate, 041-8611, Japan
- Suzuyo Research Institute, Co. Ltd., 11-26 Tsukiji-cho, Shimizu, Shizuoka, 424-0944, Japan
| | - Tomoya Yamanashi
- Suzuyo Research Institute, Co. Ltd., 11-26 Tsukiji-cho, Shimizu, Shizuoka, 424-0944, Japan
| | - Shigeru Nakayama
- Suzuyo Research Institute, Co. Ltd., 11-26 Tsukiji-cho, Shimizu, Shizuoka, 424-0944, Japan
| | - Syuetsu Ono
- Miyagi Prefecture Fisheries Cooperative Association, 1-27 Kaisei, Ishinomaki, 986-0032, Japan
| | - Koji Mikami
- Faculty of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate, 041-8611, Japan.
- College of Fisheries and Life Science, Shanghai Ocean University, 999 Huchenghuan Road, Lingang New City, Pudong District, Shanghai, 201306, China.
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