|Miller, Susan - Sue|
Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract only
Publication Acceptance Date: 7/20/2009
Publication Date: 7/20/2009
Citation: Cheng, L., Liu, J., Miller, S.S., Bucciarelli, B., Zinn, K.E., Zhang, F., Allan, D.A., Shen, J., Vance, C.P. 2009. Glycerophosphodiester phosphodiesterases play an important role in phosphate recycling and phosphate sensing in white lupin [abstract]. American Society of Plant Biologists Annual Meeting, July 18-22, 2009, Honolulu, Hawaii. Paper No. P08022. Interpretive Summary:
Technical Abstract: White lupin (Lupinus albus L.), a well adapted species to phosphate (Pi) impoverished soils, develops short, densely clustered lateral roots (cluster/proteoid roots) to increase Pi uptake. Here, we report two white lupin glycerophosphodiester phosphodiesterase (GPX-PDE) genes which share strong homology with bacteria, mammalian and plant GPX-PDE. However, phylogenetic analysis showed that these two genes belonged to different clades, suggesting functional diversity. RNA blot and qRT-PCR analysis showed that both LaGPX-PDE genes are highly upregulated in mature Pi-deficient cluster roots. A LaGPX-PDE1 promoter: GUS reporter construct showed greatest activity in root hair, phloem, and epidermal cells of the P-deficient cluster roots. Mutation of PHR1 binding site in the promoter of LaGPX-PDE1 abolished the response to P stress. Resupply of 1 mM Pi or phosphonate (Phi) directly to P-starvation roots resulted in a rapid decrease in both LaGPX-PDE transcripts. Although LaGPX-PDE transcripts were highly abundant in Pi-stressed cluster roots, protein was low to non-detectable. One of the LaGPX-PDE genes annotates as both a GPX-PDE and a PHO85 like kinase and may be bifunctional. Taken together, our results indicate that Pi signaling can be localized as well as systemic in white lupin.