Hiromu Kameoka
Personal Profile
Education:
Mar 2010: B.S. in Agriculture, The University of Tokyo
Mar 2012: M.S. in Agriculture, The University of Tokyo
Mar 2015: Ph.D. in Agriculture, The University of Tokyo
Working experience:
Apr 2015 - Mar 2018: Postdoctoral Fellow, National Institute for Basic Biology
April 2018 - May 2020: Japan Society for the Promotion of Science Research (JSPS) Fellow
June 2020 - Aug 2022: Assistant Professor, Tohoku University
Nov 2022– Current position
Research Work
Our group studies arbuscular mycorrhizal (AM) symbiosis. AM symbiosis started shortly after plant terrestrialization and is currently conserved in more than 70% of land plants. The elucidation of AM symbiosis is important for understanding plant physiology, ecology, and evolution. We aim to understand how plants and AM fungi find and recognize each other and focus on the signaling molecules. We are also trying to establish new fundamental experimental systems for AM symbiosis research, including axenic culture and transfection.
Main Achievements
A. Pure culture of AM fungi
AM fungi produce daughter spores only after colonizing host plants. This feature strictly hinders both the basic research and the agricultural use of AM fungi, because we have to culture AM fungi with host plants to produce AM fungus inoculums, which is costly and time-consuming.
We found that specific fatty acids induce spore formation in AM fungi. We focused on the finding that co-culture of AM fungi and the bacteria Paenibacillus validus induce spore formation of AM fungi without host plants and purified (S)-12-methyltetradecanoic acid, a methylbranched-chain fatty acid, from P. validus as a compound that induces spore formation in AM fungi. Furthermore, we examined the activity of several fatty acids in spore formation and found that palmitoleic acid and myristic acid strongly induces spore formation. Spores induced by palmitoleic acid can germinate, colonize host plants, and generate next-generation spores (Kameoka et al., 2019. Nat. Microbiol.; Sugiura et al., 2020. PNAS; Tanaka et al., 2022. Commun Biol). Based on these findings, we established the first pure culture system for AM fungi, which would be a breakthrough for the production of AM fungus inoculums.
B. Identification of a putative KL inactivation enzyme
KAI2 ligand (KL) is an unidentified plant hormones that regulate plant development and AM symbiosis. While the KL signaling pathway is well characterized, the KL metabolism pathways remain poorly understood.
We identified the putative KL inactivation enzyme DIENELACTONE HYDROLASE LIKE PROTEIN1 (DLP1) in the bryophyte Marchantia polymorpha (Kameoka et al., 2023. Curr. Biol.). The KL signal induces DLP1 expression. The KL responses are impaired in DLP1 overexpression lines and enhanced in dlp1 mutants. Disruption of the genes in the KL signaling pathway largely suppressed these phenotypes. Our results suggest that DLP1 acts upstream of the KL signaling pathway and negatively regulates the pathway. Furthermore, DLP1 hydrolyzes some organic compounds, implying that DLP1 is a KL inactivation enzyme, although we cannot rule out the possibility that DLP1 regulates the amount of KLs in indirect ways or the activities of the component of KL signaling genes. Our findings provide new insights into the regulation of the KL signal.
Publications
1. Kameoka H1*, Shimazaki S1, Mashiguchi K, Watanabe B, Komatsu A, Yoda A, Mizuno Y, Kodama K, Okamoto M, Nomura T Yamaguchi S, Kyozuka J* (2023) DIENELACTONE HYDROLASE LIKE PROTEIN1 negatively regulates the KAI2-ligand pathway in Marchantia polymorpha. Curr Biol 33: 3505–3513 1co-first authors *co-corresponding
2. Kameoka H*, Gutjahr C* (2022) Functions of Lipids in Development and Reproduction of Arbuscular Mycorrhizal Fungi. Plant Cell Physiol 63: 1356–1365 *co-corresponding authors
3. Kameoka H1, Tsutsui I1, Saito K, Kikuchi Y, Handa Y, Ezawa T, Hayashi H, Kawaguchi M, Akiyama K (2019) Stimulation of asymbiotic sporulation in arbuscular mycorrhizal fungi by fatty acids. Nat Microbiol 4: 1654–1660 1co-first authors
4. Kameoka H*, Maeda T, Okuma N, Kawaguchi M* (2019) Structure-specific regulation of nutrient transport and metabolism in arbuscular mycorrhizal fungi. Plant Cell Physiol 60: 2272–2281 *co-corresponding authors
5. Kameoka H, Kyozuka J (2018) Spatial regulation of strigolactone function. J Exp Bot 69: 2255–2264
6. Kameoka H, Dun EA, Lopez-Obando M, Brewer PB, de Saint Germain A, Rameau C, Beveridge CA, Kyozuka J (2016) Phloem transport of the receptor DWARF14 protein is required for full function of strigolactones. Plant Physiol 172: 1844–1852
7. Kameoka H, Kyozuka J (2015) Downregulation of rice DWARF 14 LIKE suppress mesocotyl elongation via a strigolactone independent pathway in the dark. J Genet Genomics 42: 119–124
8. Seto Y1, Kameoka H1, Yamaguchi S, Kyozuka J (2012) Recent advances in strigolactone research: chemical and biological aspects. Plant Cell Physiol 53: 1843–1853 1co-first authors
9. Kodama K, Rich MK, Yoda A, Shimazaki S, Xie X, Akiyama K, Mizuno Y, Komatsu A, Luo Y, Suzuki H, Kameoka H, Libourel C, Keller J, Sakakibara K, Nishiyama T, Nakagawa T, Mashiguchi K, Uchida K, Yoneyama K, Tanaka Y, Yamaguchi S, Shimamura M, Delaux PM, Nomura T, Kyozuka J (2022) An ancestral function of strigolactones as symbiotic rhizosphere signals. Nat Commun 13: 3974
10. Tanaka S, Hashimoto K, Kobayashi Y, Maeda T, Kameoka H, Ezawa T, Saito K, Akiyama K, Kawaguchi M (2022) Asymbiotic mass production of the arbuscular mycorrhizal fungus Rhizophagus clarus. Commun Biol 5: 43
11. Sugiura Y, Akiyama R, Tanaka S, Yano K, Kameoka H, Kawaguchi M, Akiyama K, Saito K (2020) Myristate as a carbon and energy source for the asymbiotic growth of the arbuscular mycorrhizal fungus Rhizophagus irregularis. PNAS 117: 25779-25788
12. Seto Y, Yasui R, Kameoka H, Tamiru M, Cao M, Terauchi R, Sakurada A, Hirano R, Kisugi T, Hanada A, Umehara M, Seo E, Akiyama K, Burke J, Takeda-Kamiya N, Li W, Hirano Y, Hakoshima T, Mashiguchi K, Noel JP, Kyozuka J, Yamaguchi S (2019) Strigolactone perception and deactivation by a hydrolase receptor DWARF14. Nat Commun 10: 191
13. Luo L, Takahashi M, Kameoka H, Qin R, Shiga T, Kanno Y, Seo M, Itoh M, Xu G, Kyozuka J (2019) Developmental analysis of the early steps in strigolactone-mediated axillary bud dormancy in rice. Plant J 97: 1006–1021
14. Maeda T, Kobayashi Y, Kameoka H, Okuma N, Takeda N, Yamaguchi K, Bino T, Shigenobu S, Kawaguchi M (2018) Evidence of non-tandemly repeated rDNAs and their intragenomic heterogeneity in Rhizophagus irregularis. Commun Biol 1: 87
15. Kobayashi Y, Maeda T, Yamaguchi K, Kameoka H, Tanaka S, Ezawa T, Shigenobu S, Kawaguchi M (2018) The genome of Rhizophagus clarus HR1 reveals a common genetic basis for auxotrophy among arbuscular mycorrhizal fungi. BMC Genomics 19: 465
16. Kobae Y, Kameoka H, Sugimura Y, Saito K, Ohtomo R, Fujiwara T, Kyozuka J (2018) Strigolactone biosynthesis genes of rice are required for the punctual entry of arbuscular mycorrhizal fungi into the roots. Plant Cell Physiol 59: 544–553
17. Arite T, Kameoka H, Kyozuka J (2013) Strigolactone positively controls crown root elongation in rice. J Plant Growth Regul 31: 165–172
18. Yoshida S, Kameoka H, Tempo M, Akiyama K, Umehara M, Yamaguchi S, Hayashi H, Kyozuka J, Shirasu K (2012) The D3 F-box protein is a key component in host strigolactone responses essential for arbuscular mycorrhizal symbiosis. New Phytol 196: 1208–1216
19. Minakuchi K, Kameoka H, Yasuno N, Umehara M, Luo L, Kobayashi K, Hanada A, Ueno K, Asami T, Yamaguchi S, Kyozuka J (2010) FINE CULM1 (FC1) works downstream of strigolactones to inhibit the outgrowth of axillary buds in rice. Plant Cell Physiol 51: 1127–1135
