DEGENERATED LEMMA (DEL) regulates lemma development and affects rice grain yield

You Jing; Chen Wenbo; He Zhifeng; Xiang Yan; Zhang XinFang; Wei Mi; Wu RuHui; Shen Wenqiang; Zhang Jun; Duan QianNan; He Guanghua; Li Yunfeng; Zhang Ting

doi:10.1007/s12298-023-01297-6

DEGENERATED LEMMA (DEL) regulates lemma development and affects rice grain yield

Physiol Mol Biol Plants. 2023 Mar;29(3):335-347. doi: 10.1007/s12298-023-01297-6. Epub 2023 Mar 23.

Authors

You Jing^#¹, Chen Wenbo^#¹, He Zhifeng¹, Xiang Yan¹, Zhang XinFang¹, Wei Mi¹, Wu RuHui¹, Shen Wenqiang¹, Zhang Jun¹, Duan QianNan¹, He Guanghua¹, Li Yunfeng¹, Zhang Ting¹

Affiliation

¹ Rice Research Institute, Key Laboratory of Application and Safety Control of Genetically Modified Crops, Academy of Agricultural Sciences, Southwest University, Chongqing, 400715 China.

^# Contributed equally.

Abstract

In grass, the lemma is a unique floral organ structure that directly determines grain size and yield. Despite a great deal of research on grain enlargement caused by changes in glume cells, the importance of normal development of the glume for normal grain development has been poorly studied. In this study, we investigated a rice spikelet mutant, degenerated lemma (del), which developed florets with a slightly degenerated or rod-like lemma. More importantly, del also showed a significant reduction in grain length and width, seed setting rate, and 1000-grain weight, which led to a reduction in yield. The results indicate that the mutation of the DEL gene further affects rice grain yield. Map-based cloning shows a single-nucleotide substitution from T to A within Os01g0527600/DEL/OsRDR6, causing an amino acid mutation of Leu-34 to His-34 in the del mutant. Compared with the wild type, the expression of DEL in del was significantly reduced, which might be caused by single base substitution. In addition, the expression level of tasiR-ARF in del was lower than that of the wild type. RT-qPCR results show that the expression of some floral organ identity genes was changed, which indicates that the DEL gene regulates lemma development by modulating the expression of these genes. The present results suggest that the normal expression of DEL is necessary for the formation of lemma and the normal development of grain morphology and therefore has an important effect on the yield.

Supplementary information: The online version contains supplementary material available at 10.1007/s12298-023-01297-6.

Keywords: Lemma; Map-based cloning; Rice; Spikelet; Yield.

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