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In the context of the expected rise in population and to face future climate change, the availability of seeds that enable seedling establishment in a wide-range of environmental conditions will be pivotal to agriculture productivity. The plant hormone, abscisic acid (ABA), induces dormancy during seed development. Moreover, exogenous signals, especially temperature variations at mother plant reproductive stage, have extensively described to have a major effect to modulate dormancy depth and greatly influence seed germination performance. After seed shedding, dormancy is released by ABA degradation upon imbibition and precedes the activation of germination by a second plant hormone, gibberellin (GA). Germination requires both the induction of growth in the embryo and the weakening of the protective surrounding tissues so that radicle emergence can occur. These processes involve the coordinated action of cell wall remodeling proteins to direct cell expansion for embryo axis elongation or to modify cell wall properties of the endosperm for the rupture of its micropylar zone that faces the radicle. The balance between these two hormones has been shown to integrate temperature, light or nitrate signals and act antagonistically on embryo growth and endosperm weakening. Some studies revealed the involvement of cell wall remodeling genes in seed germination and the regulation of these genes by plant hormones. Nevertheless, the exact function of most cell wall remodeling genes in seed germination processes is not clarified yet. Furthermore, how hormonal and environmental signals perceived during seed development and germination are integrated into the control of cell wall remodeling gene expression and their influence on the properties of cell walls in seeds also remains to be determined. Therefore, the main objective of my project is to determine the impact of maternal environment during seed set on cell wall characteristics of seeds and identify cell wall remodeling genes that are differentially expressed in response to environmental and hormonal (ABA/GA) signals, suggesting a potential role in the control of dormancy and germination.
I studied biology and performed lab experiments to graduate bachelor course at Tokyo Metropolitan University. I focused on plant physiology, mainly relating plant hormone auxin, during my master course at same university. I received my PhD degree from the same university in 2018. My PhD study was about the involvement of phosphorylation of phototropin1 in first positive phototropism of maize coleoptiles. I also investigated the mechanism of light-dependent gravitropism of maize roots as well as auxin biosynthesis in the tip. I had been working as Research Fellowship for Young Scientists during my PhD hired by Japan Society for the Promotion of Science. I have been investigating the molecular basis of these visible physiological phenomena in plants by molecular and genetic approaches. Understanding such relatively fundamental mechanisms is important for more global biological studies and I believe the generation of fundamental knowledge is vital for applied sciences. My project supported by AgreenSkills+ has more direct implications for improving our life, notably the resolution of the predicted food supply crisis. I will apply my skills and expertise in the project as well as gaining new insights into the molecular mechanisms of cell wall remodeling during seed germination.
Yamamoto, T., Yoshida, Y., Nakajima K., Tominaga, M., Gyohda, A., Suzuki, H., et al., 2018. Expression of RSOsPR10 in rice roots is antagonisitically regulated by jasmonate/ethylene and salicylic acid via the activator OsERF87 and the repressor OsWRKY76, respectively Plant Direct (in press). Doi: 10.1002/pld3.49.
Suzuki, H., Yokawa, K., Nakano, S., et al., 2016. Root capdependent gravitropic U-turn of maize root requires lightinduced auxin biosynthesis via the YUC pathway in the root apex. Journal of Experimental Botany, 67: 4581-4591.
Suzuki, H., Okamoto, A., Kojima, A., et al., 2014. Blue-light regulation of ZmPHOT1 and ZmPHOT2 gene expression and the possible involvement of Zmphot1 in phototropism in maize coleoptiles. Planta, 240: 251-261.
Suzuki, H., Matano, N., Nishimura, T., Koshiba, T., 2014. A 2,4-dichlorophenoxyacetic acid analog screened using a maize coleoptile system potentially inhibits indole-3-acetic acid influx in Arabidopsis thaliana. Plant Signaling and Behavior, 9:e29077. Doi: 10.4161/psb.29077.
Nishimura, T., Hayashi, K., Suzuki, H., Gyohda, A., Takaoka, C., Sakaguchi, Y., Matsumoto, S., Kasahara, H., Sakai, T., Kato, J., Kamiya, Y., Koshiba, T., 2014. YUCASIN is a potent inhibitor of YUCCA(s), a key enzyme in auxin biosynthesis. Plant Journal, 77: 352-366. Doi: 10.1111/tpj.12399.