RESUMEN
We studied the intracellular content of reduced (GSH) and oxidized (GSSG) glutathione, glutathione reductase activity, glutathione-S-transferase, and ascorbate peroxidase in morphogenic and nonmorphogenic Tatar buckwheat calli during the culture cycle as well as under the treatment with D,L-buthionine-S,R-sulfoximine (BSO), an inhibitor of γ-glutamylcysteine synthase, the first enzyme of glutathione biosynthesis. We found that, during passaging, cultures only slightly differed in total glutathione content; however, the content of GSH was higher in the morphogenic culture, whereas the content of GSSG was higher in the nonmorphogenic culture. In the morphogenic callus, the glutathione-S-transferase activity was 10-20 times higher and the glutathione reductase activity, was 2-2.5 times lower than in the nonmorphogenic callus. Under the treatment with BSO, the decrease in the GSH content in the morphogenic callus was temporary (on day 6-8 of passage), whereas that in the nonmorphogenic callus decreased within a day and remained lower than in the control throughout the entire passage. In the morphogenic callus, BSO did not affect the content of GSSG, whereas it caused GSSG accumulation in the nonmorphogenic callus. These differences are probably due to the fact that, in the BSO-containing medium, glutathione reductase is activated in the morphogenic callus and, conversely, inhibited in the nonmorphogenic callus. Although BSO caused a decrease in the total glutathione content only in the nonmorphogenic culture, the cytostatic effect of BSO was more pronounced in the morphogenic callus. In addition, BSO also had a negative effect on the differentiation ofproembryonic cell complexes in the morphogenic callus. The role of the glutathione redox status in maintaining the embryogenic activity of cultured plant cells is discussed.
Asunto(s)
Butionina Sulfoximina/farmacología , Inhibidores Enzimáticos/farmacología , Fagopyrum/metabolismo , Glutatión/metabolismo , Células Vegetales/metabolismo , Fagopyrum/citología , Glutamato-Cisteína Ligasa/antagonistas & inhibidores , Glutamato-Cisteína Ligasa/metabolismo , Glutatión Reductasa/metabolismo , Oxidación-Reducción , Proteínas de Plantas/antagonistas & inhibidores , Proteínas de Plantas/metabolismoRESUMEN
The content of soluble proteins and individual polypeptides was studied in calluses of buckwheat Fagopyrum tataricum (L.) Gaertn with different morphogenic potential. The morphogenic callus had a higher content of soluble proteins and cyclic pattern of changes in this index during passaging, which seems to be due to formation of proembryogenic cell complexes. Comparison of the protein patterns of the calluses demonstrated differences in composition and content of individual components. Morphogenic (35 and 73 kDa) and nonmorphogenic callus-specific proteins (16 and 62 kDa) have been revealed.
Asunto(s)
Fagopyrum/crecimiento & desarrollo , Morfogénesis , Proteínas de Plantas/análisis , Biomarcadores/análisis , Fagopyrum/química , Fagopyrum/citología , Péptidos/análisisRESUMEN
Time courses of the content of extracellular polymers (ECPs) in culture media of morphogenic and non-morphogenic calluses (MCs and NCs, respectively) of Tartar buckwheat Fagopyrum tataricum (L.) Gaertn. were studied during the culture cycle. It was demonstrated that MCs secreted into the medium much more ECPs compared with NCs. During the passage of MCs, two ECPs "blowouts" were observed, which preceded formation of proembryonic cell complexes (PECCs). It is supposed that the molecules secreted might be involved in PECC recycling in MCs. The maximal content of ECPs in NCs was observed by the end of stationary growth phase of the culture, which is presumably related to changes in the cell walls during callus aging.
Asunto(s)
Fagopyrum/fisiología , Polímeros/análisis , Medios de Cultivo Condicionados/química , Fagopyrum/efectos de los fármacos , Fagopyrum/crecimiento & desarrollo , Glicoproteínas/farmacología , Reguladores del Crecimiento de las Plantas/farmacologíaRESUMEN
A study was made of colchicine effect on genetic and morphological stability of morphogenic calli of the tatar buckwheat Fagopyrum tataricum (L.) Gaertn. A prolonged exposure of the morphogenic callus in colchicins-containing medium led to its morphological changes: the callus became more friable, and proembryogenic cell complexes disappeared. Genetic non-stability started from the first days of culturing in colchicine-containing indicated by amitotic divisions and K-mitoses, leading to the formation of micronuclei and increased variability in chromosome number. As a result of colchicine action, a few lines of heterogeneous calli were obtained differing in morphology, chromosome numbers, and ability to morphogenesis from the primary morphogenic callus. Genetic instability appeared in the following passages, when the treated calli were subcultured in the medium without colchicine: a wide range of abnormal nuclear division and chromosome aberrations was observed. This prolonged genetic instability was accompanied by a prominent increase in the formation of friable clones, which was 20-30 times higher than in the control. The formation of friable clones seems to result from one or two point mutations.