Showing papers on "Brassinosteroid published in 1995"
TL;DR: It is suggested that brassinosteroids confer some stress tolerance to plant cells and further suggest that the mechanisms by which these compounds exert anti-stress effects may only in part be similar to that of ABA.
Abstract: The effect of 24-epibrassinolide (EBS), a brassinosteroid, on the response of smooth bromegrass (Bromus inermis Leyss) cell suspension cultures under low and high temperature stress was evaluated. EBS minimally increased freezing tolerance of bromegrass cells by 3-5 ° C, but markedly enhanced cell viability following exposure to high temperature stress. The net effect on hardening was, however, less than that obtained with abscisic acid (ABA). Treatment of cells with EBS increased the accumulation of a subset of ABA-inducible heat-stable proteins, but unlike ABA, EBS did not induce the expression of dehydrin transcripts which hybridized to a barley dehydrin clone. EBS slightly increased the hsp90 transcript levels, while ABA reduced the level of expression. These results confirm that brassinosteroids confer some stress tolerance to plant cells and further suggest that the mechanisms by which these compounds exert anti-stress effects may only in part be similar to that of ABA.
104 citations
TL;DR: In this paper, the occurrence of a new brassinosteroid of (22S,24R)-3β,22-dihydroxy-5α-ergostan-6, named cathasterone, was demonstrated by a GC-MS analysis in cultured cells of Catharanthus roseus.
Abstract: The occurrence of a new brassinosteroid of (22S,24R)-3β,22-dihydroxy-5α-ergostan-6-one, named cathasterone, was demonstrated by a GC-MS analysis in cultured cells of Catharanthus roseus. Its endogenous level was in the range of 2–4 ng/g fw, similar to those of brassinolide and castasterone. A feeding experiment with a deuterium-labeled substrate revealed that cathasterone was converted to teasterone and typhasterol. This is the first report of the natural occurrence of cathasterone as a brassinosteroid being the biosynthetic precursor of teasterone.
70 citations
TL;DR: Brassinolide and its related compounds, brassinosteroids, applied at the early stages of conditioning shortened the conditioning period required before clover broomrape seeds would germinate after exposure to germination stimulants, such as dl-strigol and natural stimulants from red clover root exudate.
Abstract: Brassinolide [2α, 3α, 22R,23R-tetrahydroxy-24S-methyl-B-homo-7-oxa-5-α-cholestan-6-one] and its related compounds, brassinosteroids, applied at the early stages of conditioning shortened the conditioning period required before clover broomrape seeds would germinate after exposure to germination stimulants, such as dl-strigol and natural stimulants from red clover (Trifolium pratense L.) root exudate. Brassinosteroids applied after conditioning increased the rate of the seed germination induced by these stimulants. The inhibitory effect of light on seed germination when it was induced by dl-strigol could be overcome by brassinosteroids. Brassinosteroids also eliminated the inhibitory effects of light and dl-strigol applied at the early stages of conditioning. GA3 was also effective in causing seed conditioning and increased the rate of the germination induced by these stimulants. There was a relationship between brassinosteroids and GA3 in many of the experiments conducted. These findings may have practical implications in increasing the effectiveness of applying germination stimulants in the field to soils for ‘suicidal germination’ of broomrape seeds.
68 citations
TL;DR: 6-deoxocathasterone, a putative biosynthetic intermediate in the late C6-oxidation pathway, was identified as an endogenous brassinosteroid, indicating that 6- deoxocastasterone is converted to castasterone via 6alpha-hydroxycastasterone.
64 citations
TL;DR: Two isomeric metabolites have been formed in cell suspension cultures of Lycopersicon esculentum from exogenously applied 24-epi-brassinolide, strongly suggesting regiospecificity of the corresponding glucosyltransferase.
43 citations
TL;DR: Results indicate that the qualitatively different effects of the two brassinosteroids on growth of tobacco tissue may reflect their different influence on content of endogenous cytokinin.
Abstract: Two synthetic brassinosteroids, 24-epibrassinolide (24-epiBR) and 2α,3α, 17β-trihydroxy-5α-androstan-6-one (THA-BR), exhibit different effects on growth of tobacco callus tissue. When added to a culture medium containing growth-limiting amounts of auxin, 24-epiBR reduced and THA-BR increased the fresh weight yield of tissue up to 53% and 207%, respectively, after 6 weeks of cultivation. The stimulatory and inhibitory effects of the two brassinosteroids on tissue growth occurred over a broad range of concentrations without a pronounced maximum corresponding to the ‘yes or no’ type of response. Different effects of 24-epiBR and THA-BR on tissue growth were inversely proportional to the content of endogenous cytokinins. Maximum contents of predominant cytokinins N6-(△2-isopentenyl)adenine (iP) and trans-zeatin (Z) in tissues supplied with 24-epiBR in growth-inhibiting concentrations were up to 3.7 fold and 3.4 fold higher, respectively, as compared to tissues grown on media containing growth-stimulating concentrations of THA-BR. Stimulation of tissue growth by THA-BR correlated with content of endogenous IAA and an inverse correlation was found between the content of endogenous IAA and cytokinins in tissues supplied with 24-epiBR. THA-BR exhibited weak cytokinin-like activity in a bioassay based on stimulation of growth of lateral buds of pea while 24-epiBR was inactive. Results indicate that the qualitatively different effects of the two brassinosteroids on growth of tobacco tissue may reflect their different influence on content of endogenous cytokinin.
38 citations
TL;DR: Secasterone represents the first naturally occurring brassinosteroid with a 2,3-epoxy function and was identified by gas chromatography-mass spectral analysis from seeds of Secale cereale (rye).
37 citations
TL;DR: A new BR, (22R, 23R, 24S)-3α, 22, 23-trihydroxy-24-ethyl-5α-cholestan-6-one, which is termed 28-homo-typhasterol, was identified by GC-MS, in addition to 28-homoteasterone and 6-deoxocastasterone.
Abstract: Brassinosteroids (BRs) contained in rice (Oryza sativa L.) bran were extracted and highly purified. A new BR, (22R, 23R, 24S)-3α, 22, 23-trihydroxy-24-ethyl-5α-cholestan-6-one, which is termed 28-homo-typhasterol, was identified by GC-MS, in addition to 28-homoteasterone and 6-deoxocastasterone.
29 citations
TL;DR: A new brassinosteroid was detected in seeds of Apium graveolens and it was shown to be 2-deoxybrassinolide by gas chromatography-mass spectral analysis and comparison with suitable reference compounds.
25 citations
TL;DR: KM-01 is the first selective brassinosteroid inhibitor found in natural sources, and a synergistic effect with GA3 at low concentrations and an inhibitory effect on ABA were observed.
Abstract: The biological activity of KM-01, a fungal metabolite isolated from Drechslera avenae, was tested with various bioassays of known plant hormones. It inhibited the action of brassinosteroid dose dependently, whereas no activity was observed with auxin and cytokinin bioassays. Although a synergistic effect with GA3 at low concentrations and an inhibitory effect on ABA were observed, we conclude that KM-01 is the first selective brassinosteroid inhibitor found in natural sources.
16 citations
01 Jan 1995
Patent•
25 Aug 1995
TL;DR: A plant growth promoter comprising as the active ingredients (i) a jasmonic acid or jasemonate of the formula (1): as mentioned in this paper, wherein R 1 is pentyl or pentenyl and R 2 is hydrogen or alkyl, and (ii) a brassinosteroid of formula (2):
Abstract: A plant growth promoter comprising as the active ingredients (i) a jasmonic acid or jasmonate of the formula (1): ##STR1## wherein R 1 is pentyl or pentenyl and R 2 is hydrogen or alkyl, and (ii) a brassinosteroid of the formula (2): ##STR2##
Patent•
21 Feb 1995
TL;DR: In this paper, a method for inducing specific genes expression in a cotton plant to produce cotton fibers with improved fiber characteristics by treatment with a brassinosteroid, and a Cotton plant produced by this method was presented.
Abstract: Methods are disclosed to achieve an improvement in the characteristics and yield of cotton fibers. In one method, a cotton plant of the genus Gossypium in seed form or in growth stage is treated with a brassinosteroid. In another method, an ovule culture is prepared from a cotton plant of the genus Gossypium in a brassinosteroid-containing liquid medium. Cotton fibers with improved fiber characteristics are obtained from the cotton bolls of the treated plant or from the cultured ovules. Also disclosed are a method for inducing specific genes expression in a cotton plant to produce cotton fibers with improved fiber characteristics by treatment with a brassinosteroid, and a cotton plant produced by this method; as well as a novel gene capable of changing the degree of its expression found in the ovules of a cotton plant treated with a brassinosteroid, a gene capable of hybridizing with this novel gene, a recombinant plasmid containing this novel gene, a transformant containing this recombinant plasmid, and the like.
TL;DR: It is proposed that Br is a major ribosomal cistron regulator in Allium cepa L. var.
Patent•
14 Mar 1995
TL;DR: In this article, a new compound capable of remarkably controlling and inhibiting the physiological activity of brassinosteroid was obtained by culturing Drechslera avenae 10040 strain (FERM-BP-4396).
Abstract: PURPOSE:To produce a new compound capable of remarkably controlling and inhibiting the physiological activity of brassinosteroid. CONSTITUTION:The compound KM-01 of the formula. This compound is obtained by culturing Drechslera avenae 10040 strain (FERM-BP-4396), a KM-01 compound-producing fungus belonging to Drechslera under an aerobic condition, extracting the resultant cultured material and purifying it. Since this compound can control growth promotion as the plant physiological activity of brassinosteroid, it is useful as an inhibitor of germination and growth, a growth regulator, a pollination and fertilization controller, a maturation controller for fruits and a growth and function controller for a cultured cell. Physicochemical properties of the compound KM-01 of the formula; visual appearance: pale yellow oily substance; molecular formula: C24H30O5; molecular weight: 398; specific optical rotation [alpha]D : +472.8 (c-0.0272, CHCH3).