RESUMEN
Abstract: Boron is one of the most important micronutrients for plants. Plants may suffer from deficiency or with boron toxicity. Boron plays a role in significant physiological and biochemical events in plants such as synthesis of the cell wall, membrane integrity, antioxidation, transport of photosynthesis products to other organs of the plant. The enzyme activities of ascorbate peroxidase (APX), catalase (CAT), glutathione reductase (GR) and superoxide dismutase (SOD) in three different safflower cultivars (Balcı, Dinçer and Remzibey) subjected to different boric acid concentrations (0, 5, 10, 15 mM) were measured spectrophotometrically, and the changes in the expression levels of the genes that encode these enzymes were obtained by quantitative RT-qPCR. When both the spectrophotometric measurements and the mRNA values were evaluated together, both the activity and mRNA values of APX and GR enzymes were found to be the highest in the Dinçer cultivar among the varieties treated with 15 mM boric acid, while the lowest values of these enzymes were determined in the Remzibey cultivar. According to the RT-qPCR results, the lowest SOD and CAT values were determined in Remzibey. The Dinçer cultivar was found to have the highest antioxidant capacity (APX, GR) to cope with oxidative stress caused by boric acid application at high concentrations. The sensitive Remzibey cultivar was found to have the lowest antioxidant capacity to cope with such oxidative stress. Balcı was found to be closer to Dinçer than to Remzibey in terms of boron tolerance. As a result, the boron-sensitive cultivar had low antioxidant activity.
Asunto(s)
Oligoelementos/administración & dosificación , Boro/administración & dosificación , Producción de Cultivos , Carthamus tinctorius/metabolismo , Antioxidantes/metabolismo , Oligoelementos/toxicidad , Boro/toxicidad , Expresión Génica/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Carthamus tinctorius/enzimología , Carthamus tinctorius/genéticaRESUMEN
Three ω-3 fatty acid desaturase genes (CtFAD3, CtFAD7, and CtFAD8) were isolated from safflower (Carthamus tinctorius L.). Transcript analysis showed that the highest transcript levels were detected for CtFAD3 and the low transcript levels were detected for CtFAD7 and CtFAD8 in flowers. This result indicates that CtFAD3 enzyme activity is important for fatty acid desaturation in flowers. The low transcript level of CtFAD3 in developing seeds was consistent with the recorded high level of linoleic acid (18:2) and lack of linolenic acid (18:3) in safflower seed oil. At low temperatures, the induced transcription levels of ω-3 fatty acid desaturase genes in the stems and petioles were consistent with increased polyunsaturated fatty acids (PUFAs). In the roots, ω-3 fatty acid desaturase noticeably increased at low temperatures, whereas PUFA levels decreased. Interestingly, C18:3(Δ9,12,15) alcohol was specifically found in safflower roots, and showed a significant increase, indicating a flux in the acid to alcohol ratio of this compound in safflower roots.
Asunto(s)
Carthamus tinctorius/genética , Ácido Graso Desaturasas/genética , Proteínas de Plantas/genética , Temperatura , Secuencia de Aminoácidos , Carthamus tinctorius/enzimología , Carthamus tinctorius/crecimiento & desarrollo , ADN Complementario/química , ADN Complementario/genética , Ácido Graso Desaturasas/clasificación , Ácido Graso Desaturasas/metabolismo , Ácidos Grasos/metabolismo , Ácidos Grasos Insaturados/metabolismo , Flores/enzimología , Flores/genética , Flores/crecimiento & desarrollo , Regulación del Desarrollo de la Expresión Génica , Regulación Enzimológica de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Isoenzimas/clasificación , Isoenzimas/genética , Isoenzimas/metabolismo , Datos de Secuencia Molecular , Filogenia , Proteínas de Plantas/metabolismo , Raíces de Plantas/enzimología , Raíces de Plantas/genética , Raíces de Plantas/crecimiento & desarrollo , Tallos de la Planta/enzimología , Tallos de la Planta/genética , Tallos de la Planta/crecimiento & desarrollo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Semillas/enzimología , Semillas/genética , Semillas/crecimiento & desarrollo , Análisis de Secuencia de ADN , Homología de Secuencia de AminoácidoRESUMEN
In response to salinity or drought stress, many plants accumulate glycine betaine, which is a regulator of osmosis. In plants, the last step in betaine synthesis is catalyzed by betaine aldehyde dehydrogenase (BADH), a nuclear-encoded chloroplastic enzyme. Based on the conserved oligo amino acid residues of the published BADH genes from other higher plant species, a cDNA sequence, designated CtBADH, was isolated from safflower (Carthamus tinctorius L.) using a polymerase chain reaction approach. The clones were 1.7 kb on average, and contained an open reading frame predicting a polypeptide of 503 amino acids with 84.5% identity to that of Helianthus annuus. The deduced amino acid sequence showed a decapeptide, Val-Thr-Leu-Geu-Leu-Gly-Gly-Lys-Ser-Pro and Cys, which is essential for proper functioning of BADH. Phylogenetic analysis indicated that CtBADH grouped with other dicotyledonous plant BADH genes, and subgrouped in the composite family. Prediction of secondary structure and subcellular localization suggested that the protein encoded by CtBADH contains 33 coils, 15 alpha helixes, and 21 beta strands, and most likely targets the chloroplast or mitochondria.