Icroscopic images of cross-sections on the DAB brown-stained region of Selfotel Biological Activity pedicels of CFB overexpressing PSEM 89S Purity & Documentation plants along with the corresponding distal region of pedicels on the wild type (Col-0). (C) Light microscopic images of cross-sections of the green area of pedicels of CFB overexpressing plants and the corresponding distal area of pedicels of wild kind plants stained with phloroglucinol to detect lignification. (D) Cross-sections on the white stem portion of CFB overexpressing plants as well as the corresponding area of a wild-type stem, stained with phloroglucinol. (E), Images in the identical sections as in D, at greater magnification. Bars=20 .of 20 , the white stem sections have been not growing straight, but were bending sharply at random points, indicating differential development on opposing sides (Fig. 6G, arrowed). The sepals and gynoecia of all flowers, which includes those expanding around the white stem sections, have been commonly green (Fig. 6H). All floral organs had been shorter than in the wild kind (Fig. 6H), but they had been fertile and produced green siliques of normal length filled with an ordinary quantity of seeds. Siliques of strongly expressing Pro35S:CFB lines have been frequently not straight, but were bent, kinked, or curled, indicating uncoordinated cellular growth (Fig. 6C). Simply because CFB was most strongly expressed within the root, we examined whether or not overexpression of CFB had an impact on root growth. We couldn’t detect any adjust in major root elongation, the number of lateral roots, along with the responsiveness of root growth to cytokinin in CFB overexpressing plants (data not shown).CFB overexpressing plants phenocopy the hypomorphic cas1-1 allele and possess a equivalent molecular phenotypeThe albinotic inflorescence stems of CFB overexpressing plants had been strikingly comparable to the phenotype of a mutant line named cas1-1, which is a partial loss-of-function mutant on the CYCLOARTENOL SYNTHASE 1 gene (CAS1) (Babiychuk et al., 2008a, 2008b) (Fig. 8A, B). CAS1 catalyzes the cyclization of two,3-oxidosqualene into cycloartenol, a key step within the plant sterol biosynthesis pathway. In cas1-1 mutants, the concentration of two,3-oxidosqualene, that is the substrate of CAS1, is elevated (Babiychuk et al., 2008a, 2008b). Measurement of levels of metabolites of thesterol biosynthesis pathway in CFB overexpressing plants by GC-MS showed an accumulation of 2,3-oxidosqualene primarily within the white parts in the stems, where it was improved far more than 20-fold in comparison together with the corresponding wild-type tissue (Fig. 8B). The concentration of two,3-oxidosqualene inside the white stem tissue of CFB overexpressing plants was about one-third of that in cas1-1 mutants. It’s also noteworthy that the concentration of two,3-oxidosqualene in the green parts of CFB overexpressing plants was only one-third in the concentration inside the white components. The concentrations of metabolites downstream of CAS1 were not altered, with all the notable exception of sitosterol, which was significantly lowered by a factor of 1.7 (Supplementary Fig. S8A). qRT-PCR information show that the transcript levels of CAS1 have been not altered in the albinotic stem parts of CFB overexpressing plants (Fig. 8C). Taking these findings together, CFB overexpression causes no alteration in CAS1 transcript levels but leads to accumulation on the CAS1 substrate, albeit to a reduced level than in plants with altered CAS1 expression or mutated CAS1 protein. As CFB can be a cytokinin-regulated gene and seems to be involved in regulating sterol metabolism, we atte.
