Jasmonic acid interacts with abscisic acid to regulate plant responses to water stress conditions

Abstract

Phytohormones are key players in signaling environmental stress conditions. Hormone profiling together with proline accumulation were studied in leaves and roots of different mutant lines of Arabidopsis. Regulation of proline accumulation in this system seems complex and JA-deficient (jar1-1) and JA-insensitive (jai1) lines accumulating high levels of proline despite their very low ABA levels seems to discard an ABA-dependent response. However, the pattern of proline accumulation in jai1 seedlings parallels that of ABA. Under stress conditions, there is an opposite pattern of ABA accumulation in roots of jar1-1/coi1-16 (in which ABA only slightly increase) and jai1 (in which ABA increase is even higher than in WT plants). This also makes JA-ABA crosstalk complex and discards any lineal pathway that could explain this hormonal interaction.

Keywords: ABA; JA-Ile; coi1-16; drought; hormone signal transduction; jar1-1; proline.

Figure 1.

Jasmonoyl Isoleucine (JA-Ile) in leaves (top) and roots (bottom) of Arabidopsis under control conditions (CT), and after 300 min of desiccation (ST). Lines under treatment: Columbia-0 (Col-0), WT background for jar1-1 and jai1, glabra (gl-1), WT background for coi1-16, Lansberg Erecta (Ler), WT background for abi2. Data are mean values ± standard deviation of 3 independent determinations. Letters denote statistical significance after Fisher´s LSD (p ≤ 0.05) between lines under the same conditions.

Figure 2.

Abscisic acid (ABA) in leaves (top) and roots (bottom) under control conditions (CT), and after 300 min of desiccation (ST). Lines under treatment: Columbia-0 (Col-0), WT background for jar1-1 and jai1, glabra (gl-1), WT background for coi1-16, Lansberg Erecta (Ler), WT background for abi2. Data are mean values ± standard deviation of 3 independent determinations. Letters denote statistical significance after Fisher´s LSD (p ≤ 0.05) between lines under the same conditions.

Figure 3.

Proline in leaves (top) and roots (bottom) under control conditions (CT), and after 300 min of desiccation (ST). Lines under treatment: Columbia-0 (Col-0), WT background for jar1-1 and jai1, glabra (gl-1), WT background for coi1-16, Lansberg Erecta (Ler), WT background for abi2. Data are mean values ± standard deviation of 3 independent determinations. Letters denote statistical significance after Fisher´s LSD (p ≤ 0.05) between lines under the same conditions.