Hiring cell gatekeepers - ABC transporters in plant biotechnology

Abstract

In order to survive in the environment, a cell has to be able to maintain a constant influx of chemical substances which provide nourishment, it also has to dispose of endogenous or exogenous toxins as well as must perceive and exchange signalling molecules. Such movement needs to be selective and organised. This prerequisite is realized by an array of membrane transporters, channels, carriers and pumps. ATP-binding cassette (ABC) transporters constitute the largest family of membrane transport proteins found in all organisms in every life domain. Researches in recent years have shown recognition of the role that plant ABC transporters play in hormone signalling, heavy metal tolerance, as well as natural product trafficking. In this review article we present plant ABC transporters, their characteristic modular structure and importance in plant physiology. We also point out the recent discoveries that describe their role in drought tolerance by modulation of abscisic acid traffic, and their involvement in subcellular compartmentation of exogenous toxic compounds and/or natural products. Alongside the gradually increasing number of results in fundamental research, plant ABC transporters begin to emerge as novel targets for applied science. We present an outline of the work and ideas that may link genetic engineering of ABC transporters with plant biotechnology. A particular attention is paid to the possibility of alleviating the heavy metal stress and the production of secondary metabolites.