Publication Date:
2016-12-19
Description:
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 longdistance
RNA signalling mutants.
Type:
Article
,
PeerReviewed
Format:
text
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