Ethylene response pathway is essential forARABIDOPSIS A-FIFTEENfunction in floral induction and leaf senescence

Abstract

These authors contributed equally to this work.Keywords: Arabidopsis, leaf senescence, oxidative stress, ethylene, EIN2, reactive oxygen species ARABIDOPSIS A-FIFTEEN (AAF) encodes a plastid protein and was originally identified as a SENESCENCE-ASSOCIATED GENE. Previously, we found that overexpression of AAF (AAF-OX) in Arabidopsis led to accumulated reactive oxygen species and promoted leaf senescence induced by oxidative stress, which was suppressed by a null mutant, ein2-5, in ethylene response pathway. Whether AAF function is involved in ethylene biosynthesis and/or the response pathway remained unknown. Here we show that neither overexpression (AAF-OX) nor a null mutant (aaf-KO) of AAF generates a higher level of ethylene than the wild type and display a typical triple-response phenotype in etiolated seedlings treated with 1-aminocyclopropane-1-carboxylic acid (ACC). Nevertheless, ein2-5 suppresses the phenotypes of early flowering and age-dependent leaf senescence in AAF-OX plants. We reveal that a functional ethylene response is essential for AAF function in leaf senescence and floral induction, but AAF is unlikely a regulatory component integral to the ethylene pathway.Ethylene is a gaseous plant hormone with versatile functions regulating seed germination, seedling development, fruit ripening, fiber elongation, petal abscission, leaf senescence and response to stress.1 Ethylene at 1 ppm applied to dark-grown (etiolated) seedlings produces a phenotype termed the triple response, with inhibition of elongation in hypocotyls and roots, radical swelling of hypocotyls and an exaggerated curvature of the apical hook. 2Most ethylene-related mutants were identified by the tripleresponse phenotype, and genetic analyses were subsequently used to propose a relatively linear ethylene signaling pathway.

Integrating transcriptomic and metabolomic analysis to understand natural leaf senescence in sunflower

“…Transcription factors (TFs) are key proteins in the regulation of gene expression and signal transduction networks regulating different biological processes. Several TF families have been associated with leaf senescence in many species, particularly the NAC (Balazadeh et al ., , ; Guo and Gan, ; He et al ., ; Hu et al ., ; Kim et al ., , ; Matallana‐Ramirez et al ., ; Nuruzzaman et al ., ; Wang and Dane, ), MYB (Jaradat et al ., ; Zhang et al ., ), AP2 (Chen et al ., ,b; Koyama et al ., ) and WRKY (Besseau et al ., ; Miao et al ., ; Rushton et al ., ; Ulker et al ., ; Zhou et al ., ) families.…”

Análise da expressão gênica modulada por óxido nítrico na resposta de defesa de Arabidopsis thaliana à bactéria Pseudomonas syringae

“…Esses resultados sugerem que o papel do NO em estimular ou inibir a via da auxina depende do órgão da planta, folha ou raiz, em que exercerá sua função reguladora. Outro hormônio importante na resposta de defesa é o etileno(Van Loon et al 2006a;Leon- Reyes et al 2009), um importante hormônio vegetal envolvido no processo de senescência foliar e responsável pelo aspecto amarelado de folhas senescentes(Chen et al 2012). A inoculação da bactéria induziu a expressão de genes da síntese de etileno, enquanto a fumigação com NO reprimiu sua expressão tanto na selvagem como na mutante (Figura 17).…”