Gravitropic response mechanism in cereal grass shoots

摘要

The primary goal of this research is to unravel the gravitropic response mechanism in cereal grass shoots. To achieve this goal, we must first decipher the nature of the gravisensors and how they act to perceive a gravitational signal. Then, we must determine how gravity perception leads to transduction of the signal; that is, when and how hormone asymmetry is established for both of the candidate hormones, native IAA (indole-3-acetic acid) and gibberellins. Finally, it is essential to elucidate how the hormone asymmetry, once achieved, leads to asymmetric growth in an upward-bending pulvinus. Primary components of this unequal growth response mechanism include: differential protein synthesis, sucrose and starch catabolism, beta-D-glucan turnover in the cell walls, and cell wall loosening and synthesis. Our current NASA research focuses on each of these components of the gravity response. A summary of the past three years' accomplishments and the significance of these results are present.