Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
, 5 (1), 4
eCollection

Small and Round Seed 5 Gene Encodes Alpha-Tubulin Regulating Seed Cell Elongation in Rice

Affiliations

Small and Round Seed 5 Gene Encodes Alpha-Tubulin Regulating Seed Cell Elongation in Rice

Shuhei Segami et al. Rice (N Y).

Abstract

Seed size is an important trait in determinant of rice seed quality and yield. In this study, we report a novel semi-dominant mutant Small and round seed 5 (Srs5) that encodes alpha-tubulin protein. Lemma cell length was reduced in Srs5 compared with that of the wild-type. Mutants defective in the G-protein alpha subunit (d1-1) and brassinosteroid receptor, BRI1 (d61-2) also exhibited short seed phenotypes, the former due to impaired cell numbers and the latter due to impaired cell length. Seeds of the double mutant of Srs5 and d61-2 were smaller than those of Srs5 or d61-2. Furthermore, SRS5 and BRI1 genes were highly expressed in Srs5 and d61-2 mutants. These data indicate that SRS5 independently regulates cell elongation of the brassinosteroid signal transduction pathway.

Figures

Figure 1
Figure 1
Srs5 mutant phenotypes. (A) Seed morphology of T65, Srs5, Srs5/SRS5, d1-1, and d61-2. Bar = 5 mm. (B) Panicle morphology of T65, Srs5, Srs5/SRS5, d1-1, and d61-2. Arrowheads indicate panicle neck nodes. Bar = 10 cm. (C) Gross morphology of T65, Srs5, Srs5/SRS5, d1-1, and d61-2. Bar = 20 cm. (D) Seed length of T65, Srs5, Srs5/SRS5, d1-1, and d61-2. Numbers on graphs indicate average seed length ± S.D. (E) Internode length relative to the total length of the culm. Schematic representation of the internode elongation pattern of T65, Srs5, d1-1, and d61-2. IN: internode.
Figure 2
Figure 2
Comparison of inner epidermal cell length of T65, Srs5, d1-1, and d61-2. Inner epidermal cells of the lemma of WT (A), Srs5 (B), d1-1 (C), and d61-2 (D) observed by SEM. Bars = 100 μm. (E) Lemma length of the WT, Srs5, d1-1, and d61-2. (F) Inner epidermal cell length of WT, Srs5, d1-1, and d61-2. (G) Estimated cell numbers of WT, Srs5, d1-1, and d61-2. Numbers in (E-G) indicate averages ± S.D.
Figure 3
Figure 3
Positional cloning of the Srs5 gene. (A) Phenotypic distribution of F3 seed length obtained from F2 plants derived from a cross between Srs5 and Kasalath. Arrowheads indicate the average for WT, Srs5, and Kasalath. (B) Srs5 was mapped on the short arm of chromosome 11. (C) Phenotypic distribution of F3 seed length obtained from F2 plants derived from a cross between Srs5 and SL233. Arrowheads indicate the average for Srs5/Srs5 (white), Srs5/SRS5 (grey), and SRS5/SRS5 (black). (D) Linkage analysis of Srs5.
Figure 4
Figure 4
Srs5 complementation test. (A) Seed morphology of transgenic plants. Bar = 5 mm. (B) Gross morphology of transgenic plants. Bar = 10 cm. (C) Seed length of transgenic plants. Numbers on graphs in (C) indicate averages ± S.D.
Figure 5
Figure 5
Expression of SRS5. (A) Relative amounts of SRS5 mRNA in various organs were analyzed by quantitative RT-PCR. Abbreviations: S, Shoot; R, Root; SA, Shoot apex; LB, Leaf blade; LS, Leaf sheath; LJ, Lamina joint; RA, Rachis; SP, Spikelet. (B) Relative amounts of SRS5 mRNA in spikelet of WT, Srs5, d1-1, and d61-2. (C) Relative amounts of BRI1 mRNA in spikelet of WT, Srs5, d1-1, and d61-2. Bars represent S.D.
Figure 6
Figure 6
Epistatic test of Srs5 and d61-2. (A) Seed morphology of T65, Srs5, d61-2, and Srs5×d61-2. Bar = 5 mm. (B) Gross morphology of T65, Srs5, d61-2, and Srs5×d61-2. Bar = 20 cm. (C) Seed length of T65, Srs5, d61-2, and Srs5×d61-2. Numbers indicate averages ± S.D. (D) Genetic model of SRS5 function during seed elongation in rice.

Similar articles

See all similar articles

Cited by 24 PubMed Central articles

See all "Cited by" articles

References

    1. Abe Y, Mieda K, Ando T, Kono I, Yano M, Kitano H, Iwasaki Y. The SMALL AND ROUND SEED1 (SRS1/DEP2) gene is involved in the regulation of seed size in rice. Genes Genet Syst. 2010;5:327–39. doi: 10.1266/ggs.85.327. - DOI - PubMed
    1. Ashikari M, Sakakibara H, Lin S, Yamamoto T, Takashi T, Nishimura A, Angeles ER, Qian Q, Kitano H, Matsuoka M. Cytokinin oxidase regulates rice grain production. Science. 2005;5:741–5. doi: 10.1126/science.1113373. - DOI - PubMed
    1. Ashikari M, Matsuoka M. Identification, isolation and pyramiding of quantitative trait loci for rice breeding. Trends Plant Sci. 2006;5:344–50. doi: 10.1016/j.tplants.2006.05.008. - DOI - PubMed
    1. Ashikari M, Wu J, Yano M, Sasaki T, Yoshimura A. Rice gibberellin-insensitive dwarf mutant gene Dwarf 1 encodes the alpha-subunit of GTP-binding protein. Proc Natl Acad Sci USA. 1999;5:10284–9. doi: 10.1073/pnas.96.18.10284. - DOI - PMC - PubMed
    1. Ebitani T, Takeuchi Y, Nonoue Y, Yamamoto T, Takeuchi K, Yano M. Construction and evaluation of chromosome segment substitution lines carrying overlapping chromosome segments of indica rice cultivar Kasalath in a genetic background of japonica elite cultivar Koshihikari. Breed Sci. 2005;5:65–73. doi: 10.1270/jsbbs.55.65. - DOI

LinkOut - more resources

Feedback