Poster: Vegetative Development

Abs # 436: GLE4 gene is required for pattern formation during the rice embryogenesis.

Presenter:	Kamiya, Noriko , i014003d@mbox.nagoya-u.ac.jp
Authors	Kamiya, Noriko  (A)   Kitano, Hidemi  (B)   Matsuoka, Makoto  (A)
Affiliations:	(A): BioScience Center, Nagoya University (B): Faculty of Agriculture, Nagoya University

Establishment of the basic body plan such as apical-basal, radial, and dosal-ventral axes is one of the most important events during embryogenesis. We have isolated some globular embryo (gle) mutants of rice, which fail to develop almost organs and tissues such as shoot apical meristem (SAM), root apical meristem (RAM), and vascular tissue. We supposed that these mutants are categorized into two groups, that is, mutants failed to establish the basic body plan and failed to form organs and tissues after the establishment of their body plan. To categorize the gle mutants in terms of establishment of the body plan, we used six molecular markers, OSH1 as a marker of apical region, Roc1, OsSCR, OsPNH, and OsMP as markers of the radial axis, and Ramy1A as a marker of scutellum. In wild-type, OsMP, OsPNH, OsSCR, or Roc1 is expressed in each tissue of stele, pericycle, endodermis, or epidermis, respectively. Among the gle mutants, gle4 embryo expressed Roc1 and Ramy1A normally, whereas another markers showed abnormal expression pattern. On the other hand, OsPNH and OsSCR were expressed in the central region of the embryo, where OsMP was expressed. These results suggest that this mutant fails to establish the radial axis, although the mutant distinguished between outside and inside. Moreover, OSH1 was not expressed, indicating that gle4 embryo also failed to establish the apical region. Interestingly, the calli from the gle4 epicellium could regenerate adventitious shoots and roots, with abnormal morpholigy. These results indicate that GLE4 gene is required for the embryo-specific pattern formation, but not for organ formation from the calli.