Poster: Cell division

Abs # 667: A Novel role for Two NAC-like Genes in Regulating Meristematic Activity in Arabidopsis

Presenter:	Yang, Chang-Hsien , chyang@dragon.nchu.edu.tw
Authors	Shih, Ching-Fang  (A)   Yang, Chang-Hsien  (A)
Affiliations:	(A): National Chung Hsing University

NAC-like genes that contained a conserved 150 amino acid NAC domain at their N-terminus of proteins have been thought to be involved in regulation of many processes of plant development. AtNACL1and AtNACL2, with conserved NAC domain, were identified in Arabidopsis. Both AtNACL1 and AtNACL2 mRNA were detected in the inflorescence meristem, floral buds, and leaves. AtNACL1 mRNA is expressed much higher than AtNACL2 in root. Transgenic Arabidopsis plants ectopically expressed AtNACL1 or AtNACL2 were phenotypically indistinguishable from wild-type plants. By contrast, shoot and leaf formation was severe altered in T-DNA insertional or antisense mutants of AtNACL1 and AtNACL2 by producing leaves with abnormal shape and generating more shoot branches. In these mutants, the inflorescence always divided equally into two inflorescences. Moreover, cauline leaves along with several secondary inflorescence branches were produced in an internode in the inflorescence of the mutants. Further analysis indicated that the mutant phenotypes were correlated with the alteration of the expression for genes involved in meristematic development such as SERRATE and cytokinin regulating pathway such as KNAT1 in mutants of AtNACL1 and AtNACL2. To investigate AtNACL1, 2 action, yeast two-hybrid assays using AtNACL1 or AtNACL2 as a bait was carried out. Further identification and analysis of the interacting proteins should provide new insight of the function for NAC-like genes in regulating meristematic activity in plants.