The effects of GABA in plants

Abstract

Υ-aminobutyric acid (GABA) is a non-protein amino acid in a wide range of organisms. In plants, GABA is proposed to take multiple functions under non-stressed and stressed conditions. It is a key metabolite for primary and secondary pathways being an important intermediate of nitrogen metabolism and amino acid biosynthesis. In addition, the GABA metabolism through the GABA shunt provides a source for carbon skeletons and energy for down-stream biosynthetic pathways. GABA is also involved in signaling or regulatory mechanisms. It indirectly affects plant growth and development throughout the whole crop cycle and it accumulates rapidly in response to abiotic stresses. It has been shown to contribute to responses to biotic stresses through multiple mechanisms. An overactivation of the GABA shunt can help to restrict the spread of necrotrophic fungi like Botrytis. The activity of GABA against insects may be based either on a direct inhibitory effect or on an induction of down-stream defense reactions or on a combination of both mechanisms. The dual function of GABA as a metabolite and as a component of signaling pathways is a combination enabling plants to cope with different conditions. Exogenously applied GABA triggers similar effects than the intrinsic molecule and may, therefore, offer the potential to improve the overall vigor of plants.

Keywords:

• γ-aminobutyric acid
• GABA
• plant growth
• morphological responses
• physiological responses
• biotic stress
• abiotic stress
• mode of action
• signaling
• stress tolerance

PUBLIC INTEREST STATEMENT

GABA is a non-protein amino-acid that occurs naturally in plants, animals, and microorganisms, and has multiple metabolic and physiological functions in plants which positively impact vigor, growth and development and yield of plants in general and of agricultural crops in particular. The aim of this review is to present a brief overview on the metabolic pathway of GABA in plants and to compile the information on the metabolic and physiological effects of exogenously applied GABA in plants.

Competing interests

The authors declare no competing interests.

Additional information

Funding

The authors received no direct funding for this research.

Notes on contributors

Roberto Ramos-Ruiz

Roberto Ramos-Ruiz is technical director at Servalesa, a company aiming to offer products for farming which provide a differential value through their innovation and contribution to ensure healthier crops for healthier consumers. Amongst other responsibilities, Roberto is in charge of research and development. For the past decade, Servalesa has developed several research projects in collaboration with different universities and research organizations. The fundamental objective of these projects is to offer farmers technologies able to mitigate the effects caused by different kinds of plant stress with impact on crops, either biotic or abiotic, with an acceptable efficacy, no residues, a minimal impact on the environment and a toxicological profile with no effect on users and consumers through food treated with these products. Within this research activity, Servalesa has a particular interest in studying the effects on crops and impacts on human health and the environment of naturally occurring substances.