The effects of GABA in plants

Roberto Ramos-Ruiz,Gertrude Knauf-Beiter,Felix Martinez,Manuel Tejada Moral

doi:10.1080/23311932.2019.1670553

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.

Highlights

Υ-aminobutyric acid (GABA) a non-protein amino acid is an important component of the free amino acid pool of living organisms
The GABA metabolism has been shown to be involved in the recycling and reallocation of nitrogen during leaf senescence caused by abiotic stress (Jalil, Ahmad, & Ansari, 2017)
GABA is a key metabolic component in plants where it has two major functions. It acts as a substrate for different key pathways and it is evident that it plays a key role as an interface linking several primary and secondary pathways in plants

Summary

Introduction

Υ-aminobutyric acid (GABA) a non-protein amino acid is an important component of the free amino acid pool of living organisms. Further to its metabolic role, GABA acts as an endogenous signaling molecule in plant growth regulation and plant development (Carillo, 2018; Fait, Fromm, Walter, Galili, & Fernie, 2008; Renault et al, 2011). The inhibition of tomato seedling development (Malekzadeh, Khara, & Heydari, 2014) due to chilling injury could be compensated by GABA treatments which led to the enhancement of the activity of antioxidant enzymes These observations indicate that exogenous GABA has beneficial effects on plant development of non-stressed and especially of stressed plants in different phases even though details of the underlying mechanisms still need clarification

Physiological responses of plants to exogenous GABA

Conclusions