High impact information on CUT1

• With regard to the appearance and structure of the cuticle, the phenotype conferred by bdg is reminiscent of that of transgenic Arabidopsis plants that express an extracellular fungal cutinase, suggesting that bdg may be incapable of completing the polymerization of carboxylic esters in the cuticular layer of the cell wall or the cuticle proper [1].
• The outermost epidermal cell wall is specialized to withstand pathogens and natural stresses, and lipid-based cuticular polymers are the major barrier against incursions [1].
• The absence of ECR activity results in a reduction of cuticular wax load and affects VLCFA composition of seed triacylglycerols and sphingolipids, demonstrating in planta that ECR is involved in all VLCFA elongation reactions in Arabidopsis [2].
• Plants with even moderately reduced ACL activity have a complex, bonsai phenotype, with miniaturized organs, smaller cells, aberrant plastid morphology, reduced cuticular wax deposition, and hyperaccumulation of starch, anthocyanin, and stress-related mRNAs in vegetative tissue [3].
• Epidermal and seed-specific silencing of ECR activity resulted in a reduction of cuticular wax load and the VLCFA content of seed triacylglycerols, respectively, with no effects on plant morphogenesis, suggesting that the developmental phenotypes arise from abnormal sphingolipid composition [2].

Biological context of CUT1

• Scanning electron microscopy revealed that this was a severe waxless phenotype, because stems of CUT1-suppressed plants were completely devoid of wax crystals [4].
• DNA sequence analysis revealed the nature of the cer6-1, cer6-2, and cer6-2R mutations, and segregation analysis showed that CER6 is identical to CUT1, a cDNA previously mapped to a different chromosome arm [5].
• We employed the mesophyll cell-specific molecular marker, chloroplastic carbonic anhydrase, and developed an epidermal cell-specific marker, the very-long-chain fatty acid-condensing enzyme, CUT1, to assess specificity of harvested Arabidopsis leaf cell types by reverse transcription polymerase chain reaction [6].
• The promoter region of the CUT1 gene was cloned, and 1.2 kb of the sequence 5' to the translation start codon was used to direct beta-glucuronidase (GUS) expression in transgenic plants [7].
• Using the Arabidopsis expressed sequence tag database, we have identified a gene, designated CUT1, that encodes a VLCFA condensing enzyme required for cuticular wax production [4].

Anatomical context of CUT1

• The presence of substantial amounts of dicarboxylates in cuticular membranes is unexpected [8].

Associations of CUT1 with chemical compounds

• Leaves of mutant plants supported pollen germination and released chlorophyll faster than wild-type leaves when immersed in 80% ethanol, indicating a defect in the cuticular barrier [9].
• We describe here a rapid and inexpensive method, designated the toluidine-blue (TB) test, for detection of cuticular defects in whole leaves [10].
• Our results demonstrate that light is essential for CER6 transcription, and that osmotic stress and the presence of abscisic acid enhance CER6 transcript accumulation [11].
• Using gas chromatography we screened over 1,200 ethyl methane sulfonate (EMS)-mutagenized lines for alterations in the major A. thaliana wild-type stem cuticular chemicals [12].
• Our results indicate that ACL generates the cytosolic pool of acetyl-CoA, which is the substrate required for the biosynthesis of a variety of phytochemicals, including cuticular waxes and flavonoids [13].

Regulatory relationships of CUT1

• The unique wax composition of CUT1-suppressed plants together with the fact that the location of CUT1 on the genetic map did not coincide with any of the known ECERIFERUM loci suggest that we have identified a novel gene involved in wax biosynthesis [4].

Other interactions of CUT1

• Sense suppression of CUT1 in transgenic Arabidopsis plants results in waxless (eceriferum) stems and siliques as well as conditional male sterility [4].
• Here, we show that the LACS2 gene (At1g49430) is expressed in young, rapidly expanding tissues, and in leaves expression is limited to cells of the adaxial and abaxial epidermal layers, suggesting that the LACS2 enzyme may act in the synthesis of cutin or cuticular waxes [9].
• The previously cloned CER2 gene is required for the normal accumulation of cuticular waxes and encodes a novel protein [14].
• Insertional mutagenesis of Arabidopsis ecotype C24 was used to identify a novel mutant, designated wax2, that had alterations in both cuticle membrane and cuticular waxes [15].
• Arabidopsis cer5 mutants had reduced stem cuticular wax loads and accumulated sheetlike inclusions in the cytoplasm of wax-secreting cells [16].

Analytical, diagnostic and therapeutic context of CUT1

• Thus, the CUT1 promoter should be useful for genetic engineering applications that require epidermis-specific expression of genes [7].
• Here, we describe the molecular cloning and characterization of the maize (Zea mays) GLOSSY1 (GL1) gene, a component of the pathway leading to cuticular wax biosynthesis in seedling leaves [17].
• Toward this end, the mapping of the cuticular wax ( cer) mutants cer10 to cer20 was conducted to allow more efficient allelism tests with newly identified lines [12].
• Transmission electron microscopy (TEM) revealed that Arabidopsis leaf cuticle thickness ranges from only 22 nm in leaf blades to 45 nm on petioles, causing the difficulty in cuticular membrane isolation [18].

References