Poster: Reproductive development

Abs # 374: A Lily ASR Protein Plays A Role in Abscisic Acid Signaling and Confers Drought and Salt Resistance in Arabidopsis

Presenter:	Yang, Chin-Ying , emily_0318@pchome.com.tw
Authors	Wang, Co-Shine  (A)   Yang, Chin-Ying  (A)   Wang, Huei-Jing  (A)
Affiliations:	(A): Graduate Institute of Biotechnology, National Chung Hsing University

LLA23 was previously isolated from lily (Lilium longiflorum) anthers. The expression of LLA23 was induced upon abscisic acid (ABA) or dehydration treatment. The LLA23 protein contains a stretch of basic sequence that is reminiscent of a nuclear localization signal (NLS). In this report, fluorescence microscopy studies using green fluorescent protein (GFP)-fusion proteins indicate that the bipartite NLS in LLA23 exhibits nuclear localization properties. To provide genetic evidence on LLA23 func- tion, we used an overexpression approach in Arabidopsis. Constitutive expression of LLA23 under the cauliflower mosaic virus 35S promoter confers ABA insensitivity in Arabidopsis seeds and consequen- tly, a reduced degree of seed dormancy. In vegetative tissues, Arabidopsis 35S:LLA23 transgenic plants show negative effects on stomatal closure, but little effect on transpiration rate regulation. Additionally, transgenic 35S:LLA23 plants are able to germinate under unfavorable conditions, as inhibitory concent- rations of mannitol and NaCl. The ABA inducibility of LLA23 expression, together with the functional- ity of NLS in LLA23, suggest that it could play an important role modulating ABA signaling. Despite reduced sensitivity to ABA, 35S:LLA23 transgenic plants exhibit enhanced drought and salt resistance, suggesting an additional protective function of the LLA23 molecule.