Rice DENSE AND ERECT PANICLE 2 is essential for determining panicle outgrowth and elongation

The causal gene of a novel small and round seed mutant 1 (srs1) was identified in rice by map-based cloning and named SMALL AND ROUND SEED 1 (SRS1). The SRS1 gene is identical to the previously identified DENSE AND ERECT PANICLE 2 (DEP2). The SRS1/DEP2 gene encodes a novel protein of 1365 amino acids residues without known functional domains. In the longitudinal direction of the lemma, both cell length and cell number are reduced in srs1-1 compared to the wild type, whereas in the lateral cross section of the lemma, cell length in srs1-1 is greater than that in the wild type, but the cell number in srs1-1 is the same as that in wild type. These results suggest that the small and round seed phenotype of srs1-1 is due to the reduction in both cell length and cell number in the longitudinal direction, and the elongation of the cells in the lateral direction of the lemma. The SRS1 mRNA and proteins are abundant in wild type rice specifically in young organs, namely young leaves, internodes and panicles. Interestingly, the tissues expressing SRS1 are closely related to the tissues that exhibit abnormalities in the srs1 mutants.

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“…5B and C). The SRS1 gene was found to be identical to the DENSE AND ERECT PANICL 2 gene (DEP2) reported previously (Li et al, 2010).…”

Section: Photomorphogenic Phenotypes Of the Srs1 Mutantsmentioning

confidence: 72%

The SMALL AND ROUND SEED1 (SRS1/DEP2) gene is involved in the regulation of seed size in rice

Abe

Mieda

Ando³

et al. 2010

Genes Genet. Syst.

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“…This observation clearly shows that almost these genes EP2, EP3, DEP1, qPE9-1 and DEP2 directly or indirectly affects cell size/shape and/or cell division which changes plant and panicle architecture. Previous study on dep2 (Li et al 2010) reported that the expression level of cell cycle related genes like CycB1;1, CycB2;1, CycB2;2, CycD3;1, and CDKB2;1 was reduced in mutant compared to wild type while cell size remained unchanged. However, in present study we observed the change in cell shape in mutant glume ( Fig.…”

Section: Discussionmentioning

confidence: 99%

“…There are several reports on genetic and molecular mechanisms controlling panicle architecture in rice such as DEP1 (dense and erect panicle 1) (Huang et al 2009), DEP2 (dense and erect panicle 2) (Li et al 2010), DEP3 (dense and erect panicle 3) (Qiao et al 2011), EP (erect pose panicle) (Wang et al 2009), EP2 (erect panicle 2) (Zhu et al 2010) and EP3 (erect panicle 3) (Piao et al 2009). DEP1 locus is a gain-of-function mutation causing truncation of a phosphatidylethanolamine-binding protein-like domain protein.…”

Section: Introductionmentioning

confidence: 99%

Fine Mapping and Candidate Gene Analysis of Small Round Grain Mutant in Rice

Seo

Bordiya

Lee

et al. 2017

Plant Breed. Biotech.

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This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. ABSTRACT Grain size and panicle architecture are important traits determining yield. Here we report a new allele of DEP2 (dense and erect panicle 2) which has a pleiotropic effect on grain size/shape and panicle architecture. A small round grain and erect panicle mutant was obtained by treating japonica cultivar Hwacheong waxy with MNU (N-methyl-N-nitrosourea). Through fine mapping sequence analysis, we identified the single nucleotide substitution in the mutant, which caused splicing error of the first intron, on previously reported DEP2 locus in rice. Since the dep2-1 and dep2-2 have been reported in previous studies, we named this new allele as dep2-3. The dep2-3 mutant manifested reduced grain size and plant height, dense and erect panicle and erect plant architecture. When we crossed the mutant with wild type, panicle and grain of F1 plant showed intermediate phenotype, indicating that dep2-3 showed incomplete dominance, which was not reported in the previous study. Scanning electron microscopy (SEM) results showed that increase in width of mutant grain was due to the increased width of glume cells. Paraffin section of peduncle revealed that outgrowth in outer layer of peduncle compared to inner layer caused the erectness of the panicle. Our results collectively indicated that the dep2-3 might play a significant role in the regulation of grain size/shape and formation of vascular bundles.

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“…GS3, qSW5/GW5, GS5, GW8, GIF1, and TGW6 have been artificially selected and widely used in rice-breeding programs. However, the advantageous alleles of GW2, qGL3, and GW6 are present in rare varieties or subspecies and have not been actively exploited.Most genes involved in rice panicle development, such as SP1, qPE9-1, EP2, DEP2, and DEP3, influence grain size or shape (Li et al , 2010Zhou et al 2009;Zhu et al 2010;Qiao et al 2011). Moreover, based on the phenotypic analyses of null mutants, the genes involved in gibberellin and brassinosteroid biosynthesis or signaling also modulate rice grain size (Ashikari et al 1999;Yamamuro et al 2000;Hong et al 2003;Tanabe et al 2005;Nakagawa et al 2012).…”

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confidence: 99%

Natural Variations in SLG7 Regulate Grain Shape in Rice

Zhou

Peng

et al. 2015

Genetics

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Rice (Oryza sativa) grain shape, which is controlled by quantitative trait loci (QTL), has a strong effect on yield production and quality. However, the molecular basis for grain development remains largely unknown. In this study, we identified a novel QTL, Slender grain on chromosome 7 (SLG7), that is responsible for grain shape, using backcross introgression lines derived from 9311 and Azucena. The SLG7 allele from Azucena produces longer and thinner grains, although it has no influence on grain weight and yield production. SLG7 encodes a protein homologous to LONGIFOLIA 1 and LONGIFOLIA 2, both of which increase organ length in Arabidopsis. SLG7 is constitutively expressed in various tissues in rice, and the SLG7 protein is located in plasma membrane. Morphological and cellular analyses suggested that SLG7 produces slender grains by longitudinally increasing cell length, while transversely decreasing cell width, which is independent from cell division. Our findings show that the functions of SLG7 family members are conserved across monocots and dicots and that the SLG7 allele could be applied in breeding to modify rice grain appearance.KEYWORDS rice; quantitative trait loci; grain shape; cell elongation R ICE (Oryza sativa L.) is a staple food for half of the world's population (Khush 2001). Three major components, panicle number per plant, grain number per panicle, and grain weight, determine rice yield production. Grain weight is associated with grain size and shape, which are defined as grain length, grain width, and grain thickness (Duan et al. 2014). There is a striking diversity of grain size among the rice species worldwide. The grains of domesticated rice range from 3 to 11 mm in length and from 1.2 to 3.8 mm in width (Fitzgerald et al. 2009). Despite the influence of several environmental factors on plant growth and development, such as water supply and fertilizer level, the final grain size of rice is reasonably constant within a given species.Rice grain traits are quantitatively inherited. In the past decade, several quantitative trait loci (QTL) controlling grain size and shape have been cloned. GS3, encoding a transmembrane protein containing four putative domains, was the first characterized QTL that regulates grain length (Fan et al. 2006). qGL3 encodes a putative protein phosphatase with a Kelch-like repeat domain, and an aspartate-to-glutamate transition in the second Kelch domain leads to a long-grain phenotype (Zhang et al. 2012). GW6 encodes a GNAT-like protein that harbors intrinsic histone acetyltransferase activity, and an elevated expression enhances grain length and weight by enlarging spikelet hulls and accelerating grain filling (Song et al. 2015). GW2, GW5/qSW5, GS5, and GW8 were identified as regulators of rice grain width. GW2 encodes a previously unknown RING-type protein with E3 ubiquitin ligase, which negatively regulates cell division by degrading its substrate(s) through the ubiquitin-proteasome pathway (Song et al. 2007). GW5/qSW5 encodes a nuclearlocated protein t...

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Rice DENSE AND ERECT PANICLE 2 is essential for determining panicle outgrowth and elongation

Cited by 134 publications

References 39 publications

The SMALL AND ROUND SEED1 (SRS1/DEP2) gene is involved in the regulation of seed size in rice

The SMALL AND ROUND SEED1 (SRS1/DEP2) gene is involved in the regulation of seed size in rice

Fine Mapping and Candidate Gene Analysis of Small Round Grain Mutant in Rice

Natural Variations in SLG7 Regulate Grain Shape in Rice

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