Phosphorylation of BLUS1 kinase by phototropins is a primary step in stomatal opening

Takemiya, A., Sugiyama, N., Fujimoto, H., Tsutsumi, T., Yamauchi, S., Hiyama, A., Tada, Y., Christie, J.M. and Shimazaki, K. (2013) Phosphorylation of BLUS1 kinase by phototropins is a primary step in stomatal opening. Nature Communications, 4, p. 2094. (doi: 10.1038/ncomms3094)

Abstract

Opening of stomata in the plant facilitates photosynthetic CO2 fixation and transpiration. Blue-light perception by phototropins (phot1, phot2) activates the plasma membrane H+-ATPase, causing stomata to open. Here we describe a regulator that connects these components, a Ser/Thr protein kinase, BLUS1 (BLUE LIGHT SIGNALING1), which mediates a primary step for phototropin signalling in guard cells. blus1 mutants identified by infrared thermography result in a loss of blue light-dependent stomatal opening. BLUS1 encodes a protein kinase that is directly phosphorylated by phot1 in vitro and in vivo at Ser-348 within its C-terminus. Both phosphorylation of Ser-348 and BLUS1 kinase activity are essential for activation of the H+-ATPase. blus1 mutants show lower stomatal conductance and CO₂ assimilation than wild-type plants under decreased ambient CO₂. Together, our analyses demonstrate that BLUS1 functions as a phototropin substrate and primary regulator of stomatal control to enhance photosynthetic CO₂ assimilation under natural light.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Christie, Professor John
• Authors: Takemiya, A., Sugiyama, N., Fujimoto, H., Tsutsumi, T., Yamauchi, S., Hiyama, A., Tada, Y., Christie, J.M., and Shimazaki, K.
• College/School: College of Medical Veterinary and Life Sciences > School of Molecular Biosciences
• Journal Name: Nature Communications
• ISSN (Online): 2041-1723