Isolation and characterization of the gene HvFAR1 encoding acyl-CoA reductase from the cer-za.227 mutant of barley (Hordeum vulgare) and analysis of the cuticular barrier functions.

The New phytologist 2023 Sep

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The cuticle is a protective layer covering aerial plant organs. We studied the function of waxes for the establishment of the cuticular barrier in barley (Hordeum vulgare). The barley eceriferum mutants cer-za.227 and cer-ye.267 display reduced wax loads, but the genes affected, and the consequences of the wax changes for the barrier function remained unknown. Cuticular waxes and permeabilities were measured in cer-za.227 and cer-ye.267. The mutant loci were isolated by bulked segregant RNA sequencing. New cer-za alleles were generated by genome editing. The CER-ZA protein was characterized after expression in yeast and Arabidopsis cer4-3. Cer-za.227 carries a mutation in HORVU5Hr1G089230 encoding acyl-CoA reductase (FAR1). The cer-ye.267 mutation is located to HORVU4Hr1G063420 encoding β-ketoacyl-CoA synthase (KAS1) and is allelic to cer-zh.54. The amounts of intracuticular waxes were strongly decreased in cer-ye.267. The cuticular water loss and permeability of cer-za.227 were similar to wild-type (WT), but were increased in cer-ye.267. Removal of epicuticular waxes revealed that intracuticular, but not epicuticular waxes are required to regulate cuticular transpiration. The differential decrease in intracuticular waxes between cer-za.227 and cer-ye.267, and the removal of epicuticular waxes indicate that the cuticular barrier function mostly depends on the presence of intracuticular waxes. © 2023 The Authors. New Phytologist © 2023 New Phytologist Foundation.

Citation

Yannic Müller, Payal Patwari, Tyll Stöcker, Viktoria Zeisler-Diehl, Ulrike Steiner, Chiara Campoli, Lea Grewe, Magdalena Kuczkowska, Maya Marita Dierig, Sarah Jose, Alistair M Hetherington, Ivan F Acosta, Heiko Schoof, Lukas Schreiber, Peter Dörmann. Isolation and characterization of the gene HvFAR1 encoding acyl-CoA reductase from the cer-za.227 mutant of barley (Hordeum vulgare) and analysis of the cuticular barrier functions. The New phytologist. 2023 Sep;239(5):1903-1918