Poster abstracts
Poster number 16 submitted by Katelyn Amstutz
Determining the role of a plant LINC complex in stomatal closure
Katelyn Amstutz (Molecular, Cellular, and Developmental Biology Graduate Program), Norman Groves (Department of Molecular Genetics, The Ohio State University), Iris Meier (Department of Molecular Genetics, The Ohio State University)
Abstract:
As climate change worsens, droughts across the globe have increased in frequency and severity. Understanding how plants resist drought stress allows us to create crops resilient to the changing climate. Plants contain pores called stomata, which are formed from two guard cells and allow gas exchange. In response to drought, plants use the hormone Abscisic Acid (ABA) to signal stomata to close to prevent water loss. Loss of the Arabidopsis Klarsicht/ANC-1/Syne Homology (KASH) proteins AtSINE1 or AtSINE2 inhibits ABA-induced stomatal closure due to a decrease in calcium fluctuations and defects in actin reorganization. KASH proteins are localized to the outer nuclear membrane (ONM), and form Linker of Nucleoskeleton and Cytoskeleton (LINC) complexes by interacting with inner nuclear membrane SUN proteins. KASH proteins have a cytoplasmic region which interacts with the cytoskeleton, while SUN proteins can interact with the nuclear lamina. However, whether these interactions are important for SINE1 or SINE2 function during stomatal closure is unknown. In addition, the role of SUN proteins and the nuclear lamina in stomatal closure has not been determined.
Here, we have shown the role of (a) nuclear envelope association, (b) membrane association, and (c) interaction with F-actin in SINE1 and SINE2 function in stomatal closure. Mutant proteins with respective domain deletions were tagged with GFP and placed under native promoters into sine1-1 and sine2-1 mutants; subcellular localizations confirmed; and ABA-induced stomatal closure examined. Surprisingly, SINE1 did not require the ability to co-localize with F-actin to rescue stomatal closure, but did require the connection to the nuclear envelope and LINC complex, whereas all the domains of SINE2 were required for stomatal closure. SUN and nuclear lamina components were also found to be required for stomatal closure by examining ABA-induced stomatal closure in a sun double mutant, sun1-KO sun2-KD , and two nuclear lamina mutants, crwn1 and crwn4. Together this suggests a new role for SUN proteins and the nuclear lamina during stomatal closure, in addition to providing an increased understanding of the importance of SINE1 and SINE2 during stomatal closure.
Keywords: Plant Biology, LINC Complex, Nuclear Envelope