Poster: Root Biology

Abs # 526: Overexpression of OsRAA1, An Auxin Induced small protein, increased the adventitious roots initiation and reduced gravitropic response in Oryza sativa.

Presenter:	Chong, Kang , chongk@ns.ibcas.ac.cn
Authors	Chong, Kang  (A)   Ge, Lei  (A)   Zhao, Yuan  (A)   Xu, Ming-Li  (A)   Xu, Yun-Yuan  (A)   Xu, Zhi-Hong  (A)   Tan, Ke-hui  (A)
Affiliations:	(A): Institute of Botany, Chinese Academy of Sciences

A novel gene, Oryza sativa Root Architecture Associated 1 (OsRAA1) has been characterized molecularly. OsRAA1 shows tissue specific expression mainly in the apical meristem, the elongation zone of root tip, steles of the branch zone and the young lateral root. It encodes a small protein with calculated MW of 12.0 kDa. Constitutive expression of OsRAA1 under the control of maize ubiquitin promoter resulted in phenotypes of reduced growth of primary root, increased number of adventitious roots and helix primary root, delayed gravitropic response of roots in seedling of rice, which are similar to the phenotypes of the plant treated with auxin. OsRAA1 constitutive expression also caused longer leaves and sterile florets at the last stage of plant development. Analysis of Northern blot and OsRAA1::GUS transgenic plant demonstrated that the OsRAA1 expression was induced by auxin. These data suggested that OsRAA1 might be involved in the pathway of Auxin/IAA signal transduction in establishing the root architecture in rice.