The Arabidopsis 3-ketoacyl-CoA thiolase-2 (kat2-1) mutant exhibits increased flowering but reduced reproductive success

Abstract

The enzyme 3-ketoacyl-CoA thiolase (KAT) (EC 2.3.1.16) catalyses a key step in fatty acid beta-oxidation. In Arabidopsis thaliana, expression of the KAT2 gene is known to be required for the efficient mobilization of triacylglycerol during germination and seedling establishment. Here, data from the Arabidopsis kat2-1 mutant are presented, showing that perturbation of beta-oxidation also affects vegetative growth and reproductive success. In the wild type, the KAT2 protein was detected in all organs tested. In the kat2-1 mutant, rosette leaf area and dry weight, but not leaf number, were greatly increased relative to wild type. Global proliferative arrest of flowering was delayed, resulting in increased silique production in kat2-1 plants. However, total silique dry weight was not increased. kat2-1 siliques were smaller and had a reduced seed number caused by increased ovule abortion. In kat2-1 ovules, carbon flow into sugars via gluconeogeneis and respiration were both reduced in comparison to the wild type. In conclusion, these data indicate that a functional beta-oxidation pathway is required to maintain the balance between silique development and the continued initiation of floral meristems.

Antifungal activity of Saccharomyces cerevisiae peroxisomal 3-ketoacyl-CoA thiolase

“…(C) In panel 1, 10 μM purified AFP in 25 mM Hepes buffer (pH 7.2) was added to the plate; in panel 2, buffer alone was added to the plate as a negative control. flowering cessation, and global proliferative arrest (17). When considered together with these previous data, our results suggest that ScFox3 plays a role not only as a PTS2 protein for peroxisome biogenesis, but also as a defense-related protein for protection against external stresses.…”

Arabidopsis Lipins, PDAT1 Acyltransferase, and SDP1 Triacylglycerol Lipase Synergistically Direct Fatty Acids toward β-Oxidation, Thereby Maintaining Membrane Lipid Homeostasis

“…The molecular identity of the core b-oxidation pathway components and their physiological role in FA catabolism in postgerminative seedling growth in oilseeds are now well established (Graham, 2008;Theodoulou and Eastmond, 2012). Physiological understanding of b-oxidation in mature plant tissues has been defined in dark-induced (Kunz et al, 2009) or natural (Yang and Ohlrogge, 2009) senescence, reproductive development (Rylott et al, 2003;Footitt et al, 2007aFootitt et al, , 2007b, with respect to the biosynthesis of auxin (Strader and Bartel, 2011) and jasmonate (Goepfert and Poirier, 2007), and during storage TAG production (Slocombe et al, 2009;Kelly et al, 2013). The results of this study provide new insights into the regulation of the peroxisomal b-oxidation pathway and its role in membrane lipid homeostasis in leaves.…”

Función del gen 3-cetoacil-CoA tiolasa 2 (KAT2) en defensa y desarrollo. Participación de los peroxisomas en las respuestas a herida en Arabidopsis thaliana.

“…El gen KAT5, llamado previamente PEROXISOMAL 3-KETOACYL-COA THIOLASE 1 (PKT1) oPKT2, da lugar a dos mRNA diferentes por procesamiento alternativo (Carrie et al, 2007) y el gen KAT1, presenta alta homología de secuencia con el gen PED1/KAT2. De los diferentes genes KAT, el mayor nivel de expresión del gen KAT2, los fenotipos observados en el mutante ped1/kat2 y la coexpresión de este gen con otros del metabolismo de β-oxidación, a diferencia de KAT5 (Carrie et al, 2007), sugieren que este gen codifica la proteína KAT mas importante de β-oxidación en Arabidopsis (Footitt et al, 2007a).…”

“…El fenotipo de letalidad en los primeros estadios del desarrollo en los dobles mutantes acx3 acx4 (Rylott et al, 2003) y mfp2 aim1 (Rylott et al, 2006) revela la esencialidad de la β-oxidación para el desarrollo embrionario. El mutante ped1/kat2, aunque no es letal, produce semillas y silicuas más pequeñas y un mayor número de óvulos abortados, sugiriendo un papel del gen KAT2 en el desarrollo de la semilla (Germain et al, 2001;Footitt et al, 2007a).…”

“…Por el contrario, el doble mutante acx1 acx5 presenta defectos en el desarrollo del polen y una menor viabilidad de las semillas que es restituida por la aplicación exógena de JA, lo que relaciona este fenotipo con la menor producción de esta hormona (Schilmiller et al, 2007). Por último, para el mutante ped1/kat2 se han descrito alteraciones leves tanto en el desarrollo vegetativo como en el reproductivo, entre ellas una menor longitud del filamento del estambre, que no implica un retraso en su desarrollo o una menor viabilidad (Footitt et al, 2007a).…”