Phosphorylation of plasma membrane aquaporin PIP2;1 in C-terminal affects light-induced stomatal opening in Arabidopsis

• Published in: Plant signaling & behavior Vol. 15; no. 10; p. 1795394
• Main Authors: Huang, Cai-Jiao, Wang, Xiao-Hong, Huang, Jing-Yu, Zhang, Chun-Guang, Chen, Yu-Ling
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 02.10.2020
• Subjects: Light; Other; phosphorylation; plasma membrane aquaporin PIP2; Short Communication; stomatal opening
• ISSN: 1559-2316; 1559-2324; 1559-2324
• DOI: 10.1080/15592324.2020.1795394

Guard cells undergo quick volume changes during stomatal movements. However, the contribution of aquaporins to stomatal movements has not been well understood. The plasma membrane aquaporin PIP2;1in Arabidopsis has been found to mediate abscisic acid-induced or flag22-induced stomatal closure. In this research, we investigated the role of PIP2;1 in light-induced stomatal opening by measuring the stomatal apertures of the pip2;1 mutant and PIP2;1 overexpression lines after light treatment. pip2;1 mutant exhibited a larger stomatal aperture, and the overexpression lines displayed a smaller stomatal aperture. It has been reported that the phosphorylation at Ser-280 and Ser-283 of PIP2;1 in rosette tissue increased in response to darkness, whereas osmotic water permeability (P f ) in mesophyll protoplasts in darkness was lower than that under light, suggesting that phosphorylation at Ser-280 and Ser-283 of PIP2;1 affected P f in mesophyll protoplasts. Therefore, we obtained the pip2;1 mutant expressing phosphorylation-deficient (PIP2;1 AA) or phosphomimetic (PIP2;1 DD) forms of PIP2;1. The PIP2;1 AA lines exhibited a larger stomatal aperture as pip2;1 mutant, whereas PIP2;1 DD lines exhibited a smaller stomatal aperture as PIP2;1 overexpression lines under light. These results suggest that PIP2;1 plays a negative role in light-induced stomatal opening, and phosphorylation of PIP2;1 at Ser-280 and Ser-283 causes reduced water absorption in guard cells and decreased stomatal opening.