Thecer-cqu region in barley: Gene cluster or multifunctional gene

Wettstein-Knowles, Penny von; Søgaard, Bodil

doi:10.1007/bf02906514

Cited by 30 publications

(67 citation statements)

References 21 publications

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“…The isolated lipid classes and/or their derivatives (see 22) were analyzed via gas liquid chromatography (GLC) using the Hewlett-Packard instrumentation, the 3% SP-2100 and 1% Dexsil-300 columns and the conditions detailed previously (22). Association of specific groups of pleiotropic effects with alleles at various cer loci has been noted previously and discussed (9).…”

Section: Chemical Analysesmentioning

confidence: 99%

Dominant mutations atCer-yy change barley spike wax into leaf blade wax

Lundqvist¹,

Wettstein-Knowles

1982

Carlsberg Res. Commun.

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Keywords: [~-diketones, p r i m a r y alcohols, epicuticular, early maturation, elongase, lipid, biosynthesis Seventeen mutations resulting in an apparent loss of the epicuticular wax on barley spikes have been shown by complementation, test cross and F2 analyses to be dominantly inherited alterations of the Cer-yy gene. The chemical composition determined by the four alleles 966, 968, 975 and 984 differs from that determined by the wild type in that none of the [~-ketoacyi derived lipids (~-diketones, hydroxy-I~-diketones and esters containing alkan-2-ols) are synthesized while the composition of the other wax lipids (alkanes, primary alcohols, aldehydes, esters containing alkan-I-ols and free acids) is markedly altered toward that characteristic of leaf blade waxes.We suggest that the Cer-yy gene determines a regulatory component which upon mutation activates the gends) in the spike for the leaf blade acyl elongase system and at the same time represses the spike acyl and I~-ketoacyl elongase systems.

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Section: Chemical Analysesmentioning

confidence: 99%

Dominant mutations atCer-yy change barley spike wax into leaf blade wax

Lundqvist¹,

Wettstein-Knowles

1982

Carlsberg Res. Commun.

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“…65D from Botswana (44,46). Secondly, the thick, white waxy bloom present on parts of leaf blades and sheaths is not attributable to 13-diketone lipids as it is in many other Gramineae (7,26,36,42). In fact to our knowledge, this lipid class has not been reported in any sorghum wax.…”

Section: Discussionmentioning

confidence: 66%

“…The wax was separated into its component lipid classes by thin layer chromatography (TLC) using silica gel H (Merck) plates and developing them first with hexane and then with amylene stabilized chloroform or only with the second solvent. Lipid classes were visualized and recovered from the TLC plates as detailed earlier (42). The isolated lipid classes and/or their derivatives (42) were quantitatively analyzed via GC using Hewlett-Packard instrumentation and 3% SP-2100 columns (42).…”

Section: Materials and Chemical Analysesmentioning

confidence: 99%

“…Lipid classes were visualized and recovered from the TLC plates as detailed earlier (42). The isolated lipid classes and/or their derivatives (42) were quantitatively analyzed via GC using Hewlett-Packard instrumentation and 3% SP-2100 columns (42). The retention times of the esters were compared with those ofC24, C26 and C28 methyl esters and C26, C:8 and C29 esters (dodecyl, tetradecyl and pentadecyl myristate) purchased from Analabs (North Haven, Conn., USA).…”

Section: Materials and Chemical Analysesmentioning

confidence: 99%

“…Qualitative GC analyses were performed on a Packard 437 instrument with a single 2 mm (i.d.) x 1 m glass column containing 10% SE-30 on Chromosorb W,HP 80-100 mesh using conditions similar to those for the HewlettPackard instrument (42). The reported percent distributions of the trapped esters and their fatty acid moieties were estimated by triangulation.…”

Section: Materials and Chemical Analysesmentioning

confidence: 99%

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Nonan-2-ol esters in sorghum leaf epicuticular wax and their collection by preparative gas chromatography

Wettstein-Knowles

Mikkelsen

Madsen

1984

Carlsberg Res. Commun.

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Epicuticular wax from sorghum seedling leaves was isolated and analyzed by TLC and GC. Its composition was remarkably similar to that of waxes on many other Gramineae leaves with the exception that three alkan-2-ol esters (nonan-2-ol docosanoate, nonan-2-ol tetracosanoate, and nonan-2-ol hexacosanoate) were present. This was unexpected as such esters have hitherto only been reported in waxes of plants with the capability of synthesizing 13-diketone lipids. The C~,-C~s alkan-2-ol esters were separated from the C~s-C~ alkan-1-ol esters by preparative GC.The column effluent was passed through a small Dexsil-300 trap maintained at 150 ~ and the esters eluted therefrom with chloroform. This technique gave better than 90% recovery of a [1-"C]-C~. ester. INTRODUCI'IONDisclosing the I~-diketone (primarily, hentriacontan-14,16-dione and 25-hydroxyhentriacontan-14,16-dione) and esterified alkan-2-ol (primarily tridecan-2-ol and pentadecan-2-ol) biosynthetic pathways and their genetic control is our primary goal. As biological material we have used barley spikes of the eceriferum mutants which determine synthesis and deposition of the very long chain lipids on the external surface of epidermal cell walls. Since large amounts of material would spur attempts to isolate the enzymes involved, we have been looking for a plant which synthesizes one or more of the specified lipids on rapidly growing seedling leaves. Herein we identify nonan-2-ol Abbreviations: GC = gas chromatography; MS = mass spectrometry; TLC = thin layer chromatography: TMS = trimethylsilyl.Springer-Verlag

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Plant Waxes

Wettstein-Knowles¹

2016

Encyclopedia of Life Sciences

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Waxes, found primarily in the cuticle of vascular plants, prevent uncontrolled water loss. They comprise a diverse mixture of aliphatics, triterpenoids, flavonoids and/or phenolic lipids, such as, alkylresorcinols. Aliphatic carbon skeletons are fatty acid synthase (FAS) products extended by fatty acid elongase (FAE) enzyme complexes and type III polyketide synthases (PKSs) to 20–34 carbons ± keto groups that serve as substrates for associated reductive, decarb and enoic pathways plus variants thereof. Study of eceriferum ( cer ) mutants, reverse genetic molecular approaches and biochemistry have led to increasingly detailed biosynthetic pathways in Arabidopsis and the Gramineae . Nevertheless, many enzymes remain unidentified. How many FAEs and type III PKSs are specific for wax, that is, not contributing to other pathways such as sphingolipid biosynthesis, is unknown. Our knowledge is rudimentary concerning regulation of biosynthesis or translocation of aliphatics during synthesis and thereafter from the endoplasmic reticulum into and onto the cuticle's aerial surface. Key Concepts Epidermal cells synthesise secondary metabolites called waxes localised in and on the cuticle surface, which protect against water loss. Waxes include a very diverse collection of aliphatic compounds. Waxes may also include other compounds with long carbon skeletons such as phenolic lipids, for example, alkylresorcinols, that function in defence against bacteria and fungi. Primer substrates for waxes are synthesised by fatty acid synthase (FAS) in plastids. FAS products are extended by fatty acid elongases (FAEs) and type III polyketide synthases (PKSs) to give skeletons with as many as 32 carbons. Enzymes in associated pathways localised in the endoplasmic reticulum convert the long carbon skeletons into a broad range of compounds. A handful of genes participating in biosynthesis of the waxes and their translocation within the epidermal cells have been cloned and characterised. The Cer‐cqu gene cluster in barley encodes three enzymes in the β‐diketone synthase (DKS) polyketide pathway. Some of the enzymes may also participate in the synthesis of related aliphatics found in cutin, suberin and sphingolipids, for example.

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Thecer-cqu region in barley: Gene cluster or multifunctional gene

Cited by 30 publications

References 21 publications

Dominant mutations atCer-yy change barley spike wax into leaf blade wax

Dominant mutations atCer-yy change barley spike wax into leaf blade wax

Nonan-2-ol esters in sorghum leaf epicuticular wax and their collection by preparative gas chromatography

Plant Waxes

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