Title: Whole-Genome Sequencing Identifies a Rice Grain Shape Mutant, gs9–1

Abstract

Breeding for genes controlling key agronomic traits is an important goal of rice genetic improvement. To gain insight into genes controlling grain morphology, we screened M₃ plants derived from 1,000 whole-genome sequenced (WGS) M₂ Kitaake mutants to identify lines with altered grain size. RESULTS:In this study, we isolated a mutant, named fast-neutron (FN) 60-4, which exhibits a significant reduction in grain size. We crossed FN60-4 with the parental line Kitaake and analyzed the resulting backcross population. Segregation analysis of 113 lines from the BC₂F₂ population revealed that the mutant phenotype is controlled by a single semi-dominant locus. Mutant FN60-4 is reduced 20% in plant height and 8.8% in 1000-grain weight compared with Kitaake. FN60-4 also exhibits an 8% reduction in cell number and a 9% reduction in cell length along the vertical axis of the glume. We carried out whole-genome sequencing of DNA pools extracted from segregants with long grains or short grains, and revealed that one gene, LOC_Os09g02650, cosegregated with the grain size phenotype in the BC₁F₂ and BC₂F₂ populations. This mutant allele was named grain shape 9-1 (gs9-1). gs9-1 carries a 3-bp deletion that affects two amino acids. This locus is a new allele of the BC12/GDD1/MTD1 genemore » that encodes a kinesin-like protein involved in cell-cycle progression, cellulose microfibril deposition and gibberellic acid (GA) biosynthesis. The GA biosynthesis-related gene KO2 is down-regulated in gs9-1. The dwarf phenotype of gs9-1 can be rescued by adding exogenous GA3. In contrast to the phenotypes for the other alleles, the gs9-1 is less severe, consistent with the nature of the mutation, which does not disrupt the open reading frame as observed for the other alleles. In this study, we isolated a mutant, which exhibits altered grain shape and identified the mutated gene, gs9-1. Our study reveals that gs9-1 is a semi-dominant gene that carries a two-amino acid mutation. gs9-1 is allelic to the BC12/GDD1/MTD1 gene involved in GA biosynthesis. These results demonstrate the efficiency and convenience of cloning genes from the whole-genome sequenced Kitaake mutant population to advance investigations into genes controlling key agronomic traits in rice.« less

Authors:

Jiang, Liangrong  ^[1];

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Li, Guotian ^[2]; Chern, Mawsheng ^[3]; Jain, Rashmi ^[3]; Pham, Nhan T. ^[3]; Martin, Joel A. ^[4]; Schackwitz, Wendy S. ^[4]; Zhao, Juan ^[5]; Ruan, Deling ^[3]; Huang, Rongyu ^[6]; Zheng, Jingsheng ^[6]; Ronald, Pamela C. ^[3]

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+ Show Author Affiliations

1. Xiamen Univ., Xiamen (People’s Republic of China); Univ. of California, Davis, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
2. Univ. of California, Davis, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Huazhong Agricultural Univ., Hubei (China)
3. Univ. of California, Davis, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
4. USDOE Joint Genome Institute (JGI), Walnut Creek, CA (United States)
5. Huazhong Agricultural Univ., Hubei (China)
6. Xiamen Univ., Xiamen (People's Republic of China)

Publication Date:

Thu Jul 18 00:00:00 EDT 2019

Research Org.:

Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER)

OSTI Identifier:

1545157

Grant/Contract Number:  

AC02-05CH11231

Resource Type:

Accepted Manuscript

Journal Name:

Rice

Additional Journal Information:

Journal Volume: 12; Journal Issue: 1; Journal ID: ISSN 1939-8425

Publisher:

Springer Nature

Country of Publication:

United States

Language:

English

Subject:

59 BASIC BIOLOGICAL SCIENCES; Oryza sativaL.; Whole-genome sequencing; Grain shape; Fast-neutron-induced mutant population; Kitaake mutant database