Force-triggered floral rapid movement via a mechanosensitive channel
ID: 613 / 456
Proposed Symposium Title: Force-triggered floral rapid movement via a mechanosensitive channel
Xuan Zhou1, Tetsuya Higashiyama2, Shihao Su1
Affiliations: 1. School of Agriculture, Sun Yat-sen University, Shenzhen, China 2. Department of Biological Sciences, The University of Tokyo, Tokyo, Japan
Plants have evolved various approaches and mechanisms to move. Rapid movement of floral stigmas triggered by mechanical force has been documented since Darwin. Those stigmas often consist of multiple lobes, which are sensitive to touch and can close rapidly within seconds. Previous studies explored the adaptive significance of stigma movement; however, the genetic nature of sensitive stigmas remains mysterious. Here, we investigate Torenia fournieri that possesses typical sensitive stigmas. We monitored the cytosolic calcium ([Ca2+]cyt) dynamics using a Ca2+ sensor. Mechanostimulation that deforms the stigma lobe leads to a rapid increase of [Ca2+]cyt on the touched lobe followed by movement, which can be blocked by Ca2+ channel inhibitors. To characterize potential genes involved in mechanosensation, we further performed RNA-Seq and identified a candidate gene, MS1, which encodes a mechanosensitive ion channel specifically expressed in stigma parenchyma cells. Stigma of ms1 mutants shows no response to force whereas can be triggered by wound or electrical shock, suggesting the function of MS1 as a mechanical sensor. We finally demonstrate that MS1 is required for force-triggered [Ca2+]cyt signature. To conclude, we report a molecular genetic basis for force-triggered organ rapid movement via a mechanosensitive channel in plants.