RESUMEN
Stomatal immunity plays an important role during bacterial pathogen invasion. Abscisic acid (ABA) induces plants to close their stomata and halt pathogen invasion, but many bacterial pathogens secrete phytotoxin coronatine (COR) to antagonize ABA signaling and reopen the stomata to promote infection at early stage of invasion. However, the underlining mechanism is not clear. SAD2 is an importin ß family protein, and the sad2 mutant shows hypersensitivity to ABA. We discovered ABI1, which negatively regulated ABA signaling and reduced plant sensitivity to ABA, was accumulated in the plant nucleus after COR treatment. This event required SAD2 to import ABI1 to the plant nucleus. Abolition of SAD2 undermined ABI1 accumulation. Our study answers the long-standing question of how bacterial COR antagonizes ABA signaling and reopens plant stomata during pathogen invasion.
Asunto(s)
Ácido Abscísico , Aminoácidos , Proteínas de Arabidopsis , Arabidopsis , Indenos , Estomas de Plantas , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Estomas de Plantas/fisiología , Arabidopsis/microbiología , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/fisiología , Ácido Abscísico/metabolismo , Indenos/metabolismo , Indenos/farmacología , Aminoácidos/metabolismo , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/inmunología , Pseudomonas syringae/fisiología , Pseudomonas syringae/patogenicidad , Transducción de Señal , Regulación de la Expresión Génica de las Plantas , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Núcleo Celular/metabolismo , Fosfoproteínas FosfatasasRESUMEN
Photoinduced electron transfer between 2-methylanthraquinone (MeAQ) and triethylamine (TEA) in a room-temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]), was investigated by comparing the time-resolved electron paramagnetic resonance (TR-EPR) spectroscopy and the transient absorption spectroscopy. The results of TR-EPR spectroscopy, in which MeAQ was 8 mmol L(-1) and TEA was 150 mmol L(-1), indicated that the transient radical would exist longer time in [bmim][PF6] than in acetonitrile. At the delay time of 8 µs after laser excitation, the TR-EPR signal transformed from an emissive peak into an absorptive peak when the experiment was performed in [bmim][PF6]. The results of the transient absorption spectroscopy, in which MeAQ was 0.1 mmol L(-1) and TEA was 2.2 mmol L(-1), showed that the efficiency and the rate of the photoinduced electron transfer reaction in [bmim][PF6] were obviously lower than that in acetonitrile. It was concluded that various factors, such as concentration, viscosity and local structural transformation of the solution, have an influence on the process of photoinduced electron transfer in [bmim][PF6].
Asunto(s)
Absorción Fisicoquímica , Antraquinonas/química , Electrones , Etilaminas/química , Líquidos Iónicos/química , Luz , Espectroscopía de Resonancia por Spin del Electrón , Teoría Cuántica , Factores de TiempoRESUMEN
A detailed study was explored to compare the transient absorption spectra of the neat 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF(4)]) with its solution in water or acetonitrile. It was concluded that the excited triplet state (3)[bmim](+*) was produced after 266 nm laser irradiation, and then the neutral radical [bmim] and the cation radical [bmim] (2+) were formed through two possible paths. The transient absorption spectra of the neat [bmim][BF(4)] and its solution were similar but the reaction kinetics were different due to their different local structures such as dimeric or cluster. The energy transfer between excited [bmim][BF(4)] and ß-carotene further affirmed the existence of (3)[bmim](+*). And the reaction that the hydrated electron captured by [bmim](+) to produce [bmim] in solution was observed.