An approach to quantify endomembrane dynamics in pollen utilizing bioactive chemicals

Area of Science:

• Plant cell biology
• Molecular and cellular biology
• Biophysics

Background:

• Tip growth in pollen tubes and root hairs relies on directed endomembrane trafficking.
• Existing image-based data on these processes are often subjective and lack quantification.
• Quantitative descriptors are crucial for genetic and chemical genomics studies of endomembrane networks.

Purpose of the Study:

• To develop a quantitative method for analyzing endomembrane trafficking dynamics.
• To identify small molecules that perturb endomembrane trafficking in pollen tubes.
• To establish a high-throughput screening approach for dissecting the endomembrane system.

Main Methods:

• Screening of small molecules affecting the localization of RAB2:GFP, a Golgi marker, in transgenic tobacco pollen.
• Semi-automated high-throughput imaging and image analysis for quantitative assessment of vesicle dynamics.
• Quantification of vesicle area, velocity, straightness, and intensity to characterize compound-induced phenotypes.

Main Results:

• Identification of novel compounds that alter pollen tube development and endomembrane trafficking.
• Quantitative characterization of six compounds based on RAB2:GFP body dynamics.
• Development of a scoring system for quantitative comparison of compound effects.

Conclusions:

• Semi-automated image analysis enables quantitative evaluation of dynamic subcellular endomembrane phenotypes.
• This method can be applied to study effects of chemicals, mutations, or other agents on endomembrane trafficking.
• Provides a powerful strategy for quantitatively dissecting the endomembrane network.