Plant Gravity Perception
Time-lapse photography showing Arabidopsis seedling responding to 90 degrees rotation
Gravity and mechanical sensing
Gravity represents the most ubiquitous and pervasive of biological signals and its perception and response (gravimorphogenesis) play critical roles in determining overall plant development and productivity. At present, the site of gravity perception in both the root and aerial parts of the plant has been defined to the tissue level and several players in the gravi-response, such as the auxin transporter systems, have been characterized. However, we still lack a cellular and molecular understanding of how gravity and touch perception occurs and how this is translated to the precise regional regulation of growth that characterizes the gravity response in plants.
We are therefore using a combination of molecular genetics, cellular imaging and morphometric /kinematic image analyses to map cellular-level signaling events, such as Ca2+-dependent signals onto the growth response in wild-type and a range of hormone and growth-related mutants in Arabidopsis.
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Variation in how plants sense gravity
Below: Analysis of roots reorientation kinetics after a 90 degree rotation reveals natural variation in the sensitivity of plants to gravity. Data Viz Curtsy of Karl Broman.
Genetically encoded gravity sensing loci
Below: Quantitate trait locus analysis of the Arabidopsis genome identifies regions that contain genes involved in gravity perception and response. The red and blue heat map shows regions that are positively or negatively correlated with the speed of reorientation. Arabidopsis has 5 chromosomes. The higher the LOD score in that region of a chromosome the higher the probably that genes found there are involved in the trait being measured.
Data Viz Curtsy of Carl Broman. Data curtesy of Edgar Spaulding.