Conserved plant transcriptional responses to microgravity from two consecutive spaceflight experiments.

Introduction: Understanding how plants adapt to the space environment is essential, as plants will be a valuable component of long duration space missions. Several spaceflight experiments have focused on transcriptional profiling as a means of understanding plant adaptation to microgravity. However, there is limited overlap between results from different experiments.

Uncovering Transcriptional Responses to Fractional Gravity in Roots.

Although many reports characterize the transcriptional response of seedlings to microgravity, few investigate the effect of partial or fractional gravity on gene expression. Understanding plant responses to fractional gravity is relevant for plant growth on lunar and Martian surfaces. The plant signaling flight experiment utilized the European Modular Cultivation System (EMCS) onboard the International Space Station (ISS).

A Role for Inositol Pyrophosphates in the Metabolic Adaptations to Low Phosphate in .

Phosphate is a major plant macronutrient and low phosphate availability severely limits global crop productivity. In , a key regulator of the transcriptional response to low phosphate, phosphate starvation response 1 (PHR1), is modulated by a class of signaling molecules called inositol pyrophosphates (PP-InsPs). Two closely related diphosphoinositol pentakisphosphate enzymes ( and ) are responsible for the synthesis and turnover of InsP, the most implicated molecule.

Two inositol hexakisphosphate kinases drive inositol pyrophosphate synthesis in plants.

Inositol pyrophosphates are unique cellular signaling molecules with recently discovered roles in energy sensing and metabolism. Studies in eukaryotes have revealed that these compounds have a rapid turnover, and thus only small amounts accumulate. Inositol pyrophosphates have not been the subject of investigation in plants even though seeds produce large amounts of their precursor, myo-inositol hexakisphosphate (InsP6 ).

A role for lipid-mediated signaling in plant gravitropism.

Gravitropism is a universal plant response. It is initiated by the sensing of the primary signal (mass or pressure), which is then converted into chemical signals that are transduced and propagated in a precise spatial and temporal fashion, resulting in a differential growth response. Our thesis is that membrane lipids and lipid-mediated signaling pathways play critical roles in the initial signaling and in the establishment of polarity.