The DROOPING LEAF (DR) gene encoding GDSL esterase is involved in silica deposition in rice (Oryza sativa L.).

Yoye Yu,Piao Rihua,Hee-Jong Koh,Mi-Ok Woo,Jong-Seong Jeon

doi:10.1371/journal.pone.0238887

Abstract

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, dr plants exhibited drooping leaves accompanied by a small midrib, short panicle, and reduced plant height. The phenotype of the dr plant 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 and dr sequences revealed that the dr allele carried a single nucleotide substitution, glycine to aspartic acid. RNAi targeted to LOC_Os02g15230 produced same phenotypes to the dr mutation, confirming LOC_Os02g15230 as the dr gene. Microscopic observations and plant nutrient analysis of SiO2 revealed that silica was less abundant in dr leaves than in wild-type leaves. This study suggests that the dr gene is involved in the regulation of silica deposition and that disruption of silica processes lead to drooping leaf phenotypes.

Highlights

Plant architecture has substantial impacts on growth and yield as a consequence of its direct influence on photosynthesis
Rice DR gene involved in silica deposition increased numbers and abnormal arrangements of bulliform cells increased leaf distortion and contributed to leaf drooping
The dr mutant exhibited short stem lengths that produced a substantial height reduction (Fig 1A) of approximately 50% compared with the wild

Summary

Introduction

Plant architecture has substantial impacts on growth and yield as a consequence of its direct influence on photosynthesis. Erect or excessively curved leaves increase plant self-shading, thereby decreasing light interception and decreasing photosynthetic capacity. Optimal leaf shape is a critical characteristic that impacts a range of physiological functions. Enhancing leaf morphology, such as by reducing leaf drooping, is a key aim of plant breeding programs [1]. Many factors contribute to drooping leaf morphology, such as lack of midribs, abnormal arrangement of bulliform cells, modulated wax synthesis, lignin content, and silica presence. Midribs, which keep leaves upright, are thickened by cell proliferation, and promotion of cell proliferation impacts leaf phenotype [2]. Bulliform cells are found between two vascular bundles in parallel on the adaxial side of leaves. Xu et al [3] reported that

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