These authors contributed equally to this work.
Identification of Arabidopsis thaliana phloem RNAs provides a search criterion for phloem-based transcripts hidden in complex datasets of microarray experiments
Article first published online: 14 MAY 2008
© 2008 The Authors. Journal compilation © 2008 Blackwell Publishing Ltd
The Plant Journal
Volume 55, Issue 5, pages 746–759, September 2008
How to Cite
Deeken, R., Ache, P., Kajahn, I., Klinkenberg, J., Bringmann, G. and Hedrich, R. (2008), Identification of Arabidopsis thaliana phloem RNAs provides a search criterion for phloem-based transcripts hidden in complex datasets of microarray experiments. The Plant Journal, 55: 746–759. doi: 10.1111/j.1365-313X.2008.03555.x
- Issue published online: 20 AUG 2008
- Article first published online: 14 MAY 2008
- Received 25 January 2008; revised 18 April 2008; accepted 24 April 2008; published online 10 July 2008.
- laser microdissection;
Phloem-mobile signals play a major role in plant nutrition, development and communication. In the latter context, phloem-mobile RNAs have been associated with signalling between plant tissues. In this study, we focused on the identification of transcripts in the shoot phloem of the model plant Arabidopsis thaliana. To isolate transcripts expressed in phloem parenchyma cells and in companion cell–sieve element complexes, we used laser microdissection coupled to laser pressure catapulting (LMPC). Mobile transcripts in sieve elements were isolated from leaf phloem exudates. After optimization of sampling and fixation, RNA of high quality was isolated from both sources. The modifications to the RNA amplification procedure described here were well suited to production of RNA of sufficient yield and quality for microarray experiments. Microarrays hybridized with LMPC-derived phloem tissue or phloem sap RNA allowed differentiation between phloem-expressed and mobile transcript species. Using this set of phloem transcripts and comparing them with microarrays derived from databases of light, hormone and nutrient treatment experiments, we identified phloem-derived RNAs as mobile, potential long-distance signals. Our dataset thus provides a search criterion for phloem-based signals hidden in the complex datasets of microarray experiments. The availability of these comprehensive phloem transcript profiles will facilitate reverse-genetic studies and forward-genetic screens for phloem and long-distance RNA signalling mutants.