Poster: Late and Moved Abstracts

Abs # 959: The Loss of TIP1;1 Aquaporin in Arabidopsis leads to Cell and Plant Death

Presenter:	Ma, Shisong , sma2@uiuc.edu
Authors	Ma, Shisong  (A)   Quist, Tanya L (C)   Ulanov, Alexander  (B)   Joly, Robert  (C)   Bohnert, Hans J (A) (B)
Affiliations:	(A): Department of Plant Biology, University of Illinois Urbana-Champaign (B): Department of Crop Sciences, University of Illinois Urbana-Champaign (C): Department of Horticulture and Landscape Architecture, Purdue University

Aquaporins, forming a large protein family in higher plants, were thought to transport water and other small neutral molecules. Outlined below is a new finding concerning one aquaporin's (TIP1;1) possible involvement in carbohydrate routing. Reverse genetics was used to investigate TIP1;1's function. RNA interference (RNAi) reducing TIP1;1 (>90%) generated severe phenotypes, resulting in death in the most extreme lines. Less severely affected lines produced small plants, early senescence and lesion formation. While relative water content was not affected, TIP1;1 RNAi plants showed higher stomatal conductance and photosynthesis rate. In the RNAi lines, a disturbance in carbon metabolism was found with up-regulated transcripts for functions in carbon acquisition, vesicle transport, signaling and transcription, and radical oxygen stress. Metabolite profiles showed lower glucose, fructose, inositol, succinic acid, fumaric acid and malic acid, but sucrose levels were like wild type. TIP1;1 RNAi plants also contained high plastidic starch and apoplastic carbohydrate. Based on these phenotypes and TIP1;1 localization at tissue and cellular level, derived form a GFP-TIP1;1 fusion protein, a model for TIP1;1 in vesicle-based metabolite routing through or between pre-vacuolar compartments is proposed.