University of California San Diego (UC San Diego) biologists have succeeded
in visualizing the movement of abscisic acid (ABA), a key plant hormone
responsible for growth and resistance to drought. Direct tracking of ABA
allowed researchers to better understand the complex interactions involving
ABA when a plant is subjected to drought or other stress.

The researchers developed what they call a "genetically-encoded reporter" to
directly and instantaneously observe the movements of ABA within the mustard
plant Arabidopsis. The reporters, called "ABAleons," contain two colored
fluorescent proteins attached to an ABA-binding sensor protein. Once bound
to ABA, the ABAleons change their fluorescence emission, which can be
analyzed using a microscope. The researchers showed that ABA concentration
changes and waves of ABA movement could be monitored in diverse tissues and
individual cells over time and in response to stress.

The results of their study will allow researchers to conduct further
research to determine how ABA helps plants respond to drought and other
environmental stresses brought by the continuing increase in the
atmosphere's carbon dioxide concentration.

[ucsdnews.ucsd.edu]