Small and round seed 5 gene encodes alpha-tubulin regulating seed cell elongation in rice

Shuhei Segami; Izumi Kono; Tsuyu Ando; Masahiro Yano; Hidemi Kitano; Kotaro Miura; Yukimoto Iwasaki

doi:10.1186/1939-8433-5-4

Small and round seed 5 gene encodes alpha-tubulin regulating seed cell elongation in rice

Rice (N Y). 2012 Feb 27;5(1):4. doi: 10.1186/1939-8433-5-4. eCollection 2012.

Authors

Shuhei Segami¹, Izumi Kono², Tsuyu Ando³, Masahiro Yano⁴, Hidemi Kitano⁵, Kotaro Miura¹, Yukimoto Iwasaki¹

Affiliations

¹ Faculty of Biotechnology, Fukui Prefectural University, 4-1-1 Kenjojima, Matsuoka, Eiheiji-Town, Fukui 910-1195, Japan.
² Institute of the Society for Techno-innovation of Agriculture, Forestry and Fisheries, 446-1 Ippaizuka, Kamiyokoba, Tsukuba, Ibaraki 305-0854, Japan ; Laboratory of Synaptic Plasticity and Connectivity RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
³ Institute of the Society for Techno-innovation of Agriculture, Forestry and Fisheries, 446-1 Ippaizuka, Kamiyokoba, Tsukuba, Ibaraki 305-0854, Japan ; National Institute of Agrobiological Science, 2-1-1 Kannondai, Tsukuba, Ibaraki 305-8602, Japan.
⁴ National Institute of Agrobiological Science, 1-2 Ohwashi, Tsukuba, Ibaraki 305-8634 Japan.
⁵ Bioscience and Biotechnology Center, Nagoya University, Furo, Chikusa, Nagoya, Aichi 464-8601, Japan.

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.