EFFECT OF THE GABA APPLICATION ON THE EXPRESSION OF ANTIOXIDANT GENES IN PERSIAN LIME

Abstract

Background: The Persian lime (Citrus latifolia Tan.) is one of the most economically important citrus fruits in Mexico. However, it confronts a vast range of threats to reach optimal productivity. Different sources of biotic and abiotic stress cause an alteration in the metabolism of Reactive Oxygen Species (ROS), which leads a high level of oxidative stress. The application of γ-aminobutyric acid (GABA) has been shown to induce an increase in the expression of antioxidant genes in various plant species. Objective: Determine the effect of exogenous application of GABA on the expression of APX and CAT genes in Persian lime plants, as well as to determine the similarity of the coding regions of these genes with other plant species. Methodology: a GABA 1 mM solution was applied in Persian lime plants of 1 year and RNA was extracted at 0, 1, 5, 24 h after application. CAT and APX genes were amplified through RT-PCR and expression was quantified using a densitometric approach.  Results: The application of GABA generated an increase in the activity of both genes, especially at 1 hour after the application. The APX gene was the one that showed the greatest increase at 1 hour; however, 24 hours after application, the activity of this gene was repressed. The CAT gene showed an increase at 1h, and it was decreasing over time, however, it was always higher compared to the control. Sequence analysis showed a high similarity between APX from Persian lime and A. thalina and CAT between Persian lime and C. sinensis. Implications: Further studies are necessary to evaluate if the application of GABA in Persian lime helps against biotic and abiotic sources of stress. Conclusions: The application of GABA in Persian lime is a possible strategy to counteract the effects of oxidative damage caused by biotic and abiotic stress.