The ArabidopsisDCREncoding a Soluble BAHD Acyltransferase Is Required for Cutin Polyester Formation and Seed Hydration Properties

Abstract

The cuticle covering every plant aerial organ is largely made of cutin that consists of fatty acids, glycerol, and aromatic monomers. Despite the huge importance of the cuticle to plant development and fitness, our knowledge regarding the assembly of the cutin polymer and its integration in the complete cuticle structure is limited. Cutin composition implies the action of acyltransferase-type enzymes that mediate polymer construction through ester bond formation. Here, we show that a member of the BAHD family of acyltransferases (DEFECTIVE IN CUTICULAR RIDGES [DCR]) is required for incorporation of the most abundant monomer into the polymeric structure of the Arabidopsis (Arabidopsis thaliana) flower cutin. DCR-deficient plants display phenotypes that are typically associated with a defective cuticle, including altered epidermal cell differentiation and postgenital organ fusion. Moreover, levels of the major cutin monomer in flowers, 9(10),16-dihydroxy-hexadecanoic acid, decreased to an almost undetectable amount in the mutants. Interestingly, dcr mutants exhibit changes in the decoration of petal conical cells and mucilage extrusion in the seed coat, both phenotypes formerly not associated with cutin polymer assembly. Excessive root branching displayed by dcr mutants and the DCR expression pattern in roots pointed to the function of DCR belowground, in shaping root architecture by influencing lateral root emergence and growth. In addition, the dcr mutants were more susceptible to salinity, osmotic, and water deprivation stress conditions. Finally, the analysis of DCR protein localization suggested that cutin polymerization, possibly the oligomerization step, is partially carried out in the cytoplasmic space. Therefore, this study extends our knowledge regarding the functionality of the cuticular layer and the formation of its major constituent the polymer cutin.

Rice TUTOU1 Encodes a Suppressor of cAMP Receptor-Like Protein That Is Important for Actin Organization and Panicle Development

“…Panicle and spikelet development is controlled by multiple genes that function in different cellular processes, such as cuticle formation and cell differentiation (Komatsu et al, 2001;Ikeda et al, 2004;Zheng et al, 2005;Panikashvili et al, 2009). The cuticle plays an important role in rice flower morphogenesis, anther and pollen development, pathogen resistance, and salt tolerance (Bird et al, 2007;Qin et al, 2011Qin et al, , 2013.…”

Physical Interaction of Floral Organs Controls Petal Morphogenesis in Arabidopsis

“…A series of Arabidopsis mutants defective in cuticle synthesis and secretion show the biological roles of cuticles as a barrier to biotic or abiotic stresses, osmotic stress, water loss, and damage from UV radiation, and in preventing the fusion of leaves and floral organs (Yephremov et al, 1999;Pruitt et al, 2000;Krolikowski et al, 2003;Aharoni et al, 2004;Kurdyukov et al, 2006;Bessire et al, 2007;Shi et al, 2011;Wang et al, 2011). Some mutants are known to be involved in petal morphogenesis: Lack of nanoridges of petals, due to a mutation in DEFECTIVE IN CUTICULAR RIDGES (DCR, encoding a BAHD acyltransferase), CYP77A6 (cytochrome P450 family), GLYCEROL-3-PHOSPHATE ACYLTRANSFERASE6 (GPAT6), or PERMEABLE CUTICLE1 (PEC1), result in increased permeability of petals to a dye and cause organ fusion (Li-Beisson et al, 2009;Panikashvili et al, 2009;Bessire et al, 2011). Compared with these Left and right halves show the petal structure in the wild type and fop1, respectively.…”

Defective in Cuticular Ridges (DCR) of Arabidopsis thaliana, a Gene Associated with Surface Cutin Formation, Encodes a Soluble Diacylglycerol Acyltransferase

“…This indicates that the cutin contains DAG and hydroxy fatty acids in its structure. It also indicates that the enzymes involved in esterification of fatty acids or their derivatives must exist in cutin biosynthesis (22,31,34). Recently, two membrane-bound acyl-CoA:glycerol-3-phosphate acyltransferases (GPAT4 and GPAT8) have been identified from A. thaliana.…”

“…Feeding Yeast Cells with 10,16-Dihydroxyhexadecanoic Acid-Due to the commercial unavailability of 10,16-dihydroxyhexadecanoic acid, which is reported as the substrate for At5g23940 (22), we have isolated the 10,16-dihydroxyhexadecanoic acid from tomatoes and used it for feeding studies and monitored the incorporation by GC-MS. The yeast cells were unable to take up and incorporate the dihydroxy fatty acid into lipids (data not shown).…”

“…Recently, it has been shown that DCR (defective in cuticular ridges)-deficient plants have the characteristics of defective cuticle with altered epidermal cell differentiation (22). Defective cuticle in reproductive and vegetative tissues was correlated with the low abundance of 9(10),16-dihydroxyhexadecanoic acid in the cutin polymer of DCR (At5g23940)-deficient plants.…”