Kyushu University Academic Staff Educational and Research Activities Database
List of Reports
Juntaro Negi Last modified date:2020.06.18

Associate Professor / Informational biology / Department of Biology / Faculty of Sciences

1. Cawas B. Engineer, Mimi Hashimoto-Sugimoto, Juntaro Negi, Tamar Azoulay-Shemer, Wouter-Jan Rappel,, Koh Iba, Julian I. Schroeder, CO2 sensing and stomatal conductance regulation: advances and open questions, Trends Plant Sci., 2016.01, [URL], Guard cells form epidermal stomatal gas-exchange valves in plants and regulate the aperture of stomatal pores in response to changes in the carbon dioxide (CO2) concentration ([CO2]) in leaves. Moreover, the development of stomata is repressed by elevated CO2 in diverse plant species. Evidence suggests that plants can sense [CO2] changes via guard cells and via mesophyll tissues in mediating stomatal movements. We review new discoveries and open questions on mechanisms mediating CO2-regulated stomatal movements and CO2 modulation of stomatal development, which together function in the CO2 regulation of stomatal conductance and gas exchange in plants. Research in this area is timely in light of the necessity of selecting and developing crop cultivars that perform better in a shifting climate..
2. Juntaro Negi, Mimi Hashimoto-Sugimoto, kensuke kusumi, Koh Iba, New Approaches to the Biology of Stomatal Guard Cells, Plant Cell Physiol., 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. .