Defense Priming in Okra using Chemically Defined Elicitors

Abstract

Biotic and abiotic stresses pose a threat to the growth and yield of plants. With increasing population and decreasing viable land area, there is a dire need of stress-resistant crop plants. Bam-FX treatment provides a sustainable method of priming the immune systems of plants without the need of genetic modifications. Okra (Abelmoschus esculentus) seeds and seedlings were treated with chemically defined elicitors -Bam-FX solutions of different concentrations to assess its effect on seed germination and plantlet morphological growth. The gas chromatography-mass spectrometry (GCMS) and High resolution liquid chromatography-mass spectrometry (HR-LCMS/MS) were used to assess various metabolites in treated samples. We also treated some seeds with fungus (Aspergillus sp. 100 cfu/mL) or organic acids to assess the priming effect in seeds. We observed that, of the four Bam-FX concentrations initially selected, Bam-FX dilutions of 1:175, 1:250, 1:500 were most effective in inducing the most optimal seed germination and morphological growth of the seedlings. Bam-FX treatment led to most marked upregulation of carboxylic acid and fumaric acid in both Okra seeds and seedlings. The fungal infection seemed to exhibit synergistic effect against Bam-FX treatment. The treatment with organic acids seemed to induce certain metabolites, such as carbamic acid, phenylboronic acid, anthranilic acid, etc., that were not otherwise induced in the non-Bam-FX-treated samples. Bam-FX, though originally designed for optimal plant growth in space, exhibited a high potential in priming the defense mechanisms of Okra against abiotic stresses.