Action potential propagation effect on gas exchange of ABA-mutant microtomato after re-irrigation stimulus

• Published in: Environmental and experimental botany 2020-10, Vol.178, p.104149, Article 104149
• Main Authors: Silva, Fábia Barbosa da, Macedo, Francynes da Conceição Oliveira, Daneluzzi, Gabriel Silva, Capelin, Diogo, Silva, Aldeir Ronaldo, Müller, Caroline, Oliveira, Ricardo Ferraz de
• Format: Article
• Language: English
• Subjects: Abscisic acid; NCED; Notabilis; Photosynthesis; Stomata conductance; Water stress
• ISSN: 0098-8472; 1873-7307
• DOI: 10.1016/j.envexpbot.2020.104149

•The propagation of action potentials is related to the plasma membrane depolarization during water deficit.•Re-irrigation stimulus induces the evocation of action potentials in wild-type and ABA-mutants microtomatoes.•Action potentials increase A, gS and E in MTwt.•In ABA mutants, gas exchange reduction in response to action potential was due to the effects of ABA on stomatal conductance.•Action potentials may also induce photosynthesis inactivation by adjusting stromal pH. During their life cycles, plants are often subjected to periods of fluctuation between water deficit and re-irrigation events. Efficient communication and rapid signaling between the shoot and root systems are needed for adaptive stress responses. Abscisic acid (ABA) and the hydraulic signal are the main long-distance signals responsive to water deficit. Nevertheless, ABA is susceptible to interactions with electrical signals and may not be sufficient as a sign of stress in plants. Therefore, we aimed to investigate the relationship between hydraulic, chemical and electrical signals after a re-irrigation stimulus to induce changes in gas exchange of ABA mutant microtomato plants. Three genotypes of tomato, cultivar Micro-Tom (MT) (MTwt), the isogenic mutant MTnotabilis (MTnot) and transgenic MTsp12::NCED (MTNCED), were exposed to 7, 4 and 11 days under simulated drought conditions, respectively. Then, the plants were re-irrigated and we simultaneously evaluated gas exchange, electric potential and the propagation of action potentials. We found that water deficit affected the water potential of the plants and induced increased depolarization of the plasma membrane electric potential in Mtwt and MTnot. In response to re-irrigation, all genotypes propagated action potentials from root to shoot. In MTwt, the electrical signal induced increases in photosynthesis, stomatal conductance and transpiration rate. By contrast, in ABA-mutants, the gas exchange variables were reduced. These results were related to the effect of ABA and possibly JA on stomatal control and pH changes inactivating photosynthesis.