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kensuke kusumi Last modified date:2019.06.13

Lecturer / Informational biology
Department of Biology
Faculty of Sciences


Graduate School
Undergraduate School
Other Organization


E-Mail
Phone
092-802-4273
Fax
092-642-4272
Academic Degree
Ph.D.
Country of degree conferring institution (Overseas)
No
Field of Specialization
Plant Physiology
Total Priod of education and research career in the foreign country
00years00months
Research
Research Interests
  • Short open reading frames (sORFs) involved in the growth responses of plants to elevated CO2.
    keyword : carbon dioxide, short open reading frame
    2014.03~2020.03.
  • Improvement of CO2 utilization efficiency by stomatal modifications in rice
    keyword : carbon dioxide, stomata, oryza sativa, rice mutant
    2010.04~2016.03.
  • Molecular mechanism of chloroplast biogenesis
    keyword : chloroplast biogenesis, gene expression, organelle development
    1998.01.
Current and Past Project
  • Elevated carbon dioxide (CO2) generally increases both growth and yield of plants. However, in rice elevated CO2 concomitantly increases leaf temperature via stomatal closure, which has the potential to enhance the high-temperature stress and impede the rice quality. This study aims improvement of CO2 utilization efficiency and reduction of damages caused by increase of leaf temperature at high CO2 environment in rice.
Academic Activities
Papers
1. Kensuke Kusumi, Ayana Hashimura, Yoshiko Yamamoto, Juntaro Negi, Koh Iba, Contribution of the S-type anion channel SLAC1 to stomatal control and its dependence on developmental stage in rice, Plant and Cell Physiology, 10.1093/pcp/pcx142, 58, 12, 2085-2094, 2017.06, Rice production depends on water availability and carbon fixation by photosynthesis. Therefore, optimal control of stomata, which regulate leaf transpiration and CO2 absorption, is important for high productivity. SLOW ANION CHANNEL-ASSOCIATED 1 (SLAC1) is an S-type anion channel protein that controls stomatal closure in response to elevated CO2. Rice slac1 mutants showed significantly increased stomatal conductance (gs) and enhanced CO2 assimilation. To discern the contribution of stomatal regulation to rice growth, we compared gs in the wild type (WT) and two mutants, slac1 and the dominant-positive mutant SLAC1-F461A, which expresses a point mutation causing an amino acid substitution (F461A) in SLAC1, at different growth stages. Because the side group of F461 is estimated to function as the channel gate, stomata in the SLAC1-F461A mutant are expected to close constitutively. All three lines had maximum gs during the tillering stage, when the gs values were 50% higher in slac1 and 70% lower in SLAC1-F461A, compared with the WT. At the tillering stage, the gs values were highest in the first leaves at the top of the stem and lower in the second and third leaves in all three lines. Both slac1 and SLAC1-F461A retained the ability to change gs in response to the day–night cycle, and showed differences in tillering rate and plant height compared with the WT, and lower grain yield. These observations show that SLAC1 plays a crucial role in regulating stomata in rice at the tillering stage..
2. Kensuke Kusumi, Koh Iba, Establishment of the chloroplast genetic system in rice during early leaf development and at low temperatures, Frontiers in Plant Science, 10.3389/fpls.2014.00386, 5, 386, 2014.07, [URL], Chloroplasts are the central nodes of the metabolic network in leaf cells of higher plants, and the conversion of proplastids into chloroplasts is tightly coupled to leaf development. During early leaf development, the structure and function of the chloroplasts differ greatly from those in a mature leaf, suggesting the existence of a stage-specific mechanism regulating chloroplast development during this period. Here, we discuss the identification of the genes affected in low temperature-conditional mutants of rice (Oryza sativa). These genes encode factors involved in chloroplast rRNA regulation (NUS1), and nucleotide metabolism in mitochondria, chloroplasts and cytosol (V2, V3, ST1). These genes are all preferentially expressed in the early leaf developmental stage P4, and depleting them causes altered chloroplast transcription and translation, and ultimately leaf chlorosis. Therefore, it is suggested that regulation of cellular nucleotide pools and nucleotide metabolism is indispensable for chloroplast development under low temperatures at this stage. This review summarizes the current understanding of these factors and discusses their roles in chloroplast biogenesis..
3. Yuhta Nomura, Atsushi Izumi, Yoshinori Fukunaga, Kensuke Kusumi, Koh Iba, Seiya Watanabe, Yoichi Nakahira, Andreas P. M. Weber, Akira Nozawa, Yuzuru Tozawa, Diversity in Guanosine 3′,5′-Bisdiphosphate (ppGpp) Sensitivity Among Guanylate Kinases of Bacteria and Plants. , Journal of Biological Chemistry, 10.1074/jbc.M113.534768., 289, 15631-15641, 2014.04, [URL], The guanosine 3′,5′-bisdiphosphate (ppGpp) signaling system is shared by bacteria and plant chloroplasts, but its role in plants has remained unclear. Here we show that guanylate kinase (GK), a key enzyme in guanine nucleotide biosynthesis that catalyzes the conversion of GMP to GDP, is a target of regulation by ppGpp in chloroplasts of rice, pea, and Arabidopsis. Plants have two distinct types of GK that are localized to organelles (GKpm) or to the cytosol (GKc), with both enzymes being essential for growth and development. We found that the activity of rice GKpm in vitro was inhibited by ppGpp with a Ki of 2.8 μM relative to the substrate GMP, whereas the Km of this enzyme for GMP was 73 μM. The IC50 of ppGpp for GKpm was ~10 μM. In contrast, the activity of rice GKc was insensitive to ppGpp, as was that of GK from baker′s yeast, which is also a cytosolic enzyme. These observations suggest that ppGpp plays a pivotal role in the regulation of GTP biosynthesis in chloroplasts through specific inhibition of GKpm activity, with the regulation of GTP biosynthesis in chloroplasts thus being independent of that in the cytosol. We also found that GKs of Escherichia coli and Synechococcus elongatus PCC 7942 are insensitive to ppGpp, in contrast to the ppGpp sensitivity of the Bacillus subtilis enzyme. Our biochemical characterization of GK enzymes has thus revealed a novel target of ppGpp in chloroplasts and has uncovered diversity among bacterial GKs with regard to regulation by ppGpp..
4. Mimi Hashimoto-Sugimoto, Juntaro Negi, Kensuke Kusumi, Koh Iba, New Approaches to the Biology of Stomatal Guard Cells, 10.1093/pcp/pct145, 55, 2, 241-250, 2014.02, [URL], CO2 acts as an environmental signal that regulates stomatal movements. High CO2 concentrations reduce stomatal aperture, whereas low concentrations trigger stomatal opening. In contrast to our advanced understanding of light and drought stress responses in guard cells, the molecular mechanisms underlying stomatal CO2 sensing and signaling are largely unknown. Leaf temperature provides a convenient indicator of transpiration, and can be used to detect mutants with altered stomatal control. To identify genes that function in CO2 responses in guard cells, CO2-insensitive mutants were isolated through high-throughput leaf thermal imaging. The isolated mutants are categorized into three groups according to their phenotypes: (i) impaired in stomatal opening under low CO2 concentrations; (ii) impaired in stomatal closing under high CO2 concentrations; and (iii) impaired in stomatal development. Characterization of these mutants has begun to yield insights into the mechanisms of stomatal CO2 responses. In this review, we summarize the current status of the field and discuss future prospects..
5. Negi, J., Moriwaki, K., Konishi, M., Yokoyama, R., Nakano, T., Kusumi, K., Hashimoto-Sugimoto, M., Schroeder, J.I., Nishitani, K., Yanagisawa, S. and Iba, K. , A Dof transcription factor, SCAP1, is essential for the development of functional stomata in Arabidopsis., Current Biology, 10.1093/pcp/pct145, 55, 241-250, 2013.02, Stomata are highly specialized organs that consist of pairs of guard cells and regulate gas and water vapor exchange in plants [1-3]. Although early stages of guard cell differentiation have been described [4-10] and were interpreted in analogy to processes of cell type differentiation in animals [11], the downstream development of functional stomatal guard cells remains poorly understood. We have isolated an Arabidopsis mutant, stomatal carpenter 1 (scap1), that develops irregularly shaped guard cells and lacks the ability to control stomatal aperture, including CO2-induced stomatal closing and light-induced stomatal opening. SCAP1 was identified as a plant-specific Dof-type transcription factor expressed in maturing guard cells, but not in guard mother cells. SCAP1 regulates the expression of genes encoding key elements of stomatal functioning and morphogenesis, such as K(+) channel protein, MYB60 transcription factor, and pectin methylesterase. Consequently, ion homeostasis was disturbed in scap1 guard cells, and esterification of extracellular pectins was impaired so that the cell walls lining the pores did not mature normally. We conclude that SCAP1 regulates essential processes of stomatal guard cell maturation and functions as a key transcription factor regulating the final stages of guard cell differentiation..
6. Kusumi, K., Hirotsuka, S., Kumamaru, T. and Iba, K. , Increased leaf photosynthesis caused by elevated stomatal conductance in a rice mutant deficient in SLAC1, a guard cell anion channel protein., Journal of Experimental Botany, 10.1093/jxb/ers216, 63, 15, 5635-5644, 2012.08, [URL], In rice (Oryza sativa L.), leaf photosynthesis is known to be highly correlated with stomatal conductance; however, it remains unclear whether stomatal conductance dominantly limits the photosynthetic rate. SLAC1 is a stomatal anion channel protein controlling stomatal closure in response to environmental [CO2]. In order to examine stomatal limitations to photosynthesis, we isolated and characterized a SLAC1-deficient mutant of rice. A TILLING screen of NMU-derived mutant lines was conducted for the rice SLAC1 ortholog gene Os04g0674700, and four mutant lines containing mutations within the open reading frame were obtained. A second screen using an infrared thermography camera revealed that one of the mutants, named slac1, had a constitutive low-leaf-temperature phenotype. Measurement of leaf gas exchange showed that slac1 plants grown in the greenhouse had significantly higher stomatal conductance (gs), rates of photosynthesis (A) and ratios of internal [CO2] to ambient [CO2] (Ci/Ca) compared to wild-type plants, whereas there was no significant difference in the response of photosynthesis to internal [CO2] (A/Ci curves). These observations demonstrate that in well-watered conditions, stomatal conductance is a major determinant of photosynthetic rate in rice. .
7. Kusumi, Kensuke; Sakata, Chikako; Nakamura, Takahiro; Kawasaki, Shinji; Yoshimura, Atsushi; Iba, Koh, A plastid protein NUS1 is essential for build-up of the genetic system for early chloroplast development under cold stress condition, The Plant Journal, 2011.09.
8. Kusumi, K., Hirotsuka, S., Shimada, H., Chono, Y., Matsuda, O. and Iba, K., Contribution of chloroplast biogenesis to carbon-nitrogen balance during early leaf development in rice, J. Plant Res. , 123, 4, 617-622, 2010.01.
9. Yoo, S-C., Cho, S-H., Sugimoto, H., Li, Jinjie., Kusumi, K., Koh, H-J., Iba, K. and Paek, N-C. , Rice Virescent-3 and Stripe-1 encoding the large and small subunits of ribonucleotide reductase are required for chloroplast biogenesis during early leaf development., Plant Physiol. , 150: 388-401, 2009.05.
10. Sugimoto, H., Kusumi, K., Noguchi, K., Yano, M., Yoshimura, A., and Iba, K., The rice nuclear gene, VIRESCENT 2, is essential for chloroplast development and encodes a novel type of guanylate kinase targeted to plastids and mitochondria., Plant Journal, 52: 512-527, 2007.11.
11. Kusumi, K., Yaeno, T., Kojo, K., Hirayama, M., Hirokawa, D., Yara, A., and Iba, K., The role of salicylic acid in the glutathione-mediated protection against photo-oxidative stress in rice, Physiol. Plant., 128: 651-661, 2006.12.
12. K. Kusumi, A. Yara, N. Mitsui, Y. Tozawa, and K. Iba, Characterization of a rice nuclear-encoded plastid RNA polymerase gene OsRpoTp, Plant Cell Physiol., 10.1093/pcp/pch133, 45, 9, 1194-1201, 45 (9) : 1194-1201 (2004), 2004.09.
Presentations
1. sORFs associated with Nitrogen metabolism in Arabidopsis.
2. sORFs associated with CO2 adaptation in Arabidopsis.
3. 楠見 健介, 橋村 綾菜, 射場 厚, Contribution of guard cell SLAC1 anion channel to the growth stage-dependent stomatal regulation in rice
, 17th International Congress on Photosynthesis Research, 2016.08, [URL], Rice cultivation mainly depends on soil water availability as well as on carbon fixation by photosynthesis. Therefore, optimal control of stomata, which regulates leaf respiration and CO2 absorption simultaneously, is crucial for healthy growth. SLAC1 is a stomatal anion channel protein controlling stomatal closure in response to environmental [CO2]. SLAC1-deficient mutant of rice, slac1, exhibited significant increase in stomatal conductance (gs) with enhanced CO2 assimilation, showing that this channel plays a major role in stomatal closure in rice. In this study, in order to clarify contribution of the SLAC1 to stomatal regulation, we investigated changes in the stomatal conductance during the vegetative growth stage of rice, and compared them among the wild type (WT), slac1 and SLAC1-F461A, which expressed a dominant point mutation (F461A) causing constitutive stomatal closure. .
4. SLAC1 is a stomatal anion channel protein controlling stomatal closure. We previously reported that the SLAC1-deficient mutant of rice, slac1, had constitutively higher stomatal conductance compared to wild type. On the other hand, change in the stomatal conductance in response to some environmental cues, such as day-night cycle and change in the external [CO2], still remained in slac1, suggesting the possible existence of SLAC1-independent mechanism regulating stomatal closure. In this study, we examined transgenic rice, SLAC1-F461A, which expressed a point mutation causing an amino acid substitution (F461A) in SLAC1. Because side group of F461 is estimated to function as the channel gate, stomata in the SLAC1-F461A are expected to close constitutively. SLAC1-F461A plant had a high-leaf-temperature phenotype, and measurement of leaf transpiration showed that the stomatal conductance of young leaves of the SLAC1-F461A was about 70% lower than that of wild type. These indicate that in the SLAC1-F461A SLAC1 channels are always open and the stomata close constitutively. We will discuss the effect of the mutation on the growth and photosynthesis and contribution of SLAC1 to stomatal regulation during rice growth..
5. Short open reading frames associated with CO2 adaptation in Arabidopsis.
6. SLAC1 is a stomatal anion channel protein controlling stomatal closure. We previously reported that the SLAC1-deficient mutant of rice, slac1, had constitutively higher stomatal conductance compared to wild type. On the other hand, change in the stomatal conductance in response to some environmental cues, such as day-night cycle and change in the external [CO2], still remained in slac1, suggesting the possible existence of SLAC1-independent mechanism regulating stomatal closure. In this study, we examined transgenic rice, SLAC1-F461A, which expressed a point mutation causing an amino acid substitution (F461A) in SLAC1. Because side group of F461 is estimated to function as the channel gate, stomata in the SLAC1-F461A are expected to close constitutively. SLAC1-F461A plant had a high-leaf-temperature phenotype, and measurement of leaf transpiration showed that the stomatal conductance of young leaves of the SLAC1-F461A was about 70% lower than that of wild type. These indicate that in the SLAC1-F461A SLAC1 channels are always open and the stomata close constitutively. We will discuss the effect of the mutation on the growth and photosynthesis and contribution of SLAC1 to stomatal regulation during rice growth..
7. 楠見 健介, 射場 厚, Modulation and maintenance of chloroplast genetic system during early leaf development and at low temperatures in rice, Japanese-Finnish Seminar 2014 "Design of Superior Machinery of Light Energy Conversion in Photosynthetic Organisms", 2014.10, Chloroplast biogenesis is most significant during the changes in cellular organization associated with leaf development in higher plants. During early leaf development, the structure and function of the chloroplasts differ greatly from those in a mature leaf, suggesting the existence of a stage-specific mechanism regulating chloroplast development during this period. We have analyzed genes involved specifically in early chloroplast biogenesis by using low temperature-conditional mutants of rice (Oryza sativa). These genes encode factors involved in chloroplast rRNA regulation (NUS1), and nucleotide metabolism in mitochondria, chloroplasts and cytosol (V2, V3, ST1). These are all preferentially expressed in the early leaf developmental stage P4, and depleting them causes altered chloroplast transcription and translation, and ultimately leaf chlorosis. Accordingly, regulation of cellular nucleotide pools and nucleotide metabolism is likely to be involved in the chloroplast biogenesis under low temperatures at this stage. Current understanding of these factors and organization of them during early leaf development will be discussed..
8. SLAC1 is a stomatal anion channel protein controlling stomatal closure in response to environmental [CO2]. Our previous study showed that the SLAC1-deficient mutant of rice, slac1, had higher stomatal conductance, higher rates of photosynthesis and lower leaf temperature compared to the wild-type plants, revealing that SLAC1 was involved in stomatal closure in rice, as was observed in Arabidopsis. On the other hand, change in the stomatal conductance in response to day-night cycle as well as to the external [CO2] still remained in the slac1 mutant, suggesting the possible existence of SLAC1-independent mechanism regulating stomatal closure. To estimate the contribution of SLAC1 to stomatal closure, we examined the effect of different developmental stage and different leaf position on SLAC1 gene expression and the stomatal conductance in the slac1 mutant and wild-type plants. Our data suggest the tissue-specificity and age-dependency of SLAC1 function in the stomatal closure in rice..
9. In rice (Oryza sativa L.), leaf photosynthesis is known to be highly correlated with stomatal conductance. Hower, it remains unclear whether stomatal conductance dominantly limits the photosynthetic rate. SLAC1 is a stomatal anion channel protein controlling stomatal closure in response to environmental [CO2]. In order to examine stomatal limitations to photosynthesis, we isolated and characterized a SLAC1-deficient mutant of rice, slac1. The slac1 plant had a constitutive low-leaf-temperature phenotype. Measurement of leaf gas exchange showed that slac1 plants had significantly higher stomatal conductance (gs), rates of photosynthesis (A) and ratios of internal [CO2] to ambient [CO2] (Ci/Ca) compared to wild-type plants, whereas there was no significant difference in the response of photosynthesis to internal [CO2] (A/Ci curves). These observations demonstrate that stomatal conductance is a major determinant of photosynthetic rate in rice..
10. Characterization of SLAC1-deficient mutant of rice.
11. Regulation of chloroplast biogenesis during early stages of leaf development in rice., [URL].
Membership in Academic Society
  • Japanese Society for Plant Cell and Molecular Biology
  • The Botanical Society of Japan
  • The Japanese Society of Plant Physiologists