IBIP seminar – MISTRAL Summer School

Tuesday, July 10, 2018
at 4:00 pm, amphi 206


Light-induced stomatal opening and regulation of plasma membrane H+-ATPase: from basic science to applications

Toshinori Kinoshita
Institute of Transformative Bio-Molecules (ITbM), Nagoya University, Japan

Stomata in the plant epidermis control gas exchange between plants and atmosphere. Stomatal aperture is regulated by many environmental signals, such as light, water status, temperature, and CO2. Under blue light, plasma membrane (PM) H+-ATPase in stomatal guard cells is activated via blue light-receptor phototropins and a signaling mediator BLUS1. Blue light-activated PM H+-ATPase provides driving force for stomatal opening. However, details of the signaling between phototropins and PM H+-ATPase remain largely unknown.
Recently, we identified a Raf-like protein kinase, BLUE LIGHT-DEPENDENT H+-ATPASE PHOSPHORYLATION (BHP) by combination of chemical screening and reverse genetic approach. Guard cells in the bhp mutant showed impairments of stomatal opening and PM H+-ATPase phosphorylation in response to blue light. BHP is abundantly expressed in the cytosol of guard cells and interacts with BLUS1. Based on these results, we concluded that BHP is a novel signaling component in blue light-dependent stomatal opening, likely downstream of BLUS1 (Sci. Rep. 2017). Moreover, we identified novel compounds, which affect stomatal movements, by chemical screening (Plant Cell Physiol. 2018). Further investigations revealed that two stomatal closing compounds (SCL1 and SCL2) suppressed blue light-induced phosphorylation of PM H+-ATPase without affecting ABA-dependent responses. In addition, I’d like to talk about recent progresses on the regulation of PM H+-ATPase activity except for stomatal guard cells (Plant Physiol. 2012; 2016; Nat. Chem. Biol. 2018).
Based on the results from these basic researches, we have tried to control stomatal aperture by the transgenic technique and using the identified compounds, and found that enhancement of light-induced stomatal opening increases photosynthesis and plant growth (PNAS 2014), and that suppression of stomatal opening confers tolerance to drought stress in plants (Front. Plant Sci. 2013; Plant Cell Physiol. 2018). These results clearly indicate that manipulation of stomatal aperture is very useful technique for controlling plant growth and survive.

Contact : Anne-Aliénor Véry