title: QTL analysis of internode elongation in response to gibberellin in deepwater rice.
abstract: Gibberellin (GA) is a plant hormone that has important roles in numerous plant developmental phases. Rice plants known as deepwater rice respond to flooding by elongating their internodes to avoid anoxia. Previous studies reported that GA is essential for internode elongation in deepwater rice. Quantitative trait locus (QTL) analyses identified QTLs regulating internode elongation in response to deepwater conditions. However, the interaction between internode elongation and regulators of GA sensitivity in deepwater rice is unknown. In this study, we applied GA to recombinant inbred lines of T65 (non-deepwater rice) and Bhadua (deepwater rice), and performed a QTL analysis of internode elongation in response to GA. GA-induced internode elongation was detected only in deepwater rice. Our QTL analysis revealed two major QTLs on chromosomes 3 and 9 regulating total internode length, lowest elongated internode and number of elongated internodes. Furthermore, the QTL on chromosome 3 acted as an enhancer of other QTLs (e.g. the QTL on chromosome 12). Nearly isogenic lines of deepwater rice carrying the QTL regions from chromosomes 3 and 12 of the deepwater rice C9285 showed internode elongation in response to GA. Thus, these QTLs may regulate GA responsiveness in deepwater rice. This study furthers our understanding of the mechanism of internode elongation in rice.
authors.affiliation: Bioscience and Biotechnology Center, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 464-8601, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Nagai
authors.affiliation: Bioscience and Biotechnology Center, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 464-8601, Japan.
authors.forename: Yuma
authors.initials: Y
authors.lastname: Kondo
authors.affiliation: Bioscience and Biotechnology Center, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 464-8601, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Kitaoka
authors.affiliation: Bioscience and Biotechnology Center, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 464-8601, Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Noda
authors.affiliation: Bioscience and Biotechnology Center, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 464-8601, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kuroha
authors.affiliation: Bioscience and Biotechnology Center, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 464-8601, Japan.
authors.forename: Rosalyn B
authors.initials: RB
authors.lastname: Angeles-Shim
authors.affiliation: Plant Breeding Laboratory, Kyushu University, 6-10-1 Hakozaki-ku, Higashi, Fukuoka 812-8581, Japan.
authors.forename: Hideshi
authors.initials: H
authors.lastname: Yasui
authors.affiliation: Plant Breeding Laboratory, Kyushu University, 6-10-1 Hakozaki-ku, Higashi, Fukuoka 812-8581, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yoshimura
authors.affiliation: Bioscience and Biotechnology Center, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 464-8601, Japan ashi@agr.nagoya-u.ac.jp.
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Ashikari
keywords: Deepwater rice; QTL.; gibberellin response; internode elongation