TheDROOPING LEAF(DR) gene encoding GDSL esterase is involved in silica deposition in rice (Oryza sativaL.)

Leaf morphology is one of the most important agronomic traits in rice breeding because of its contribution to crop yield. The drooping leaf (dr) mutant was developed from the Ilpum rice cultivar by ethyl methanesulfonate (EMS) mutagenesis. Compared with the wild type,drplants exhibited drooping leaves accompanied by a small midrib, short panicle, and reduced plant height. The phenotype of thedrplant was caused by a mutation within a single recessive gene on chromosome 2,dr(LOC_Os02g15230), which encodes a GDSL esterase. Analysis of wild-type anddrsequences revealed that thedrallele carried a single nucleotide substitution, glycine to aspartic acid. RNAi targeted to LOC_Os02g15230 produced same phenotypes to thedrmutation, confirming LOC_Os02g15230 as thedrgene. Microscopic observations and plant nutrient analysis of SiO(2)revealed that silica was less abundant indrleaves than in wild-type leaves. This study suggests that thedrgene is involved in the regulation of silica deposition and that disruption of silica processes lead to drooping leaf phenotypes.