The Promoters of Forisome Genes MtSEO2 and MtSEO3 Direct Gene Expression to Immature Sieve Elements in Medicago truncatula and Nicotiana tabacum
- 144 Downloads
Forisomes are mechanoproteins that function as valves in the phloem sieve tubes of the Fabaceae. Changes in the Ca2+ level that occur after wounding trigger an instantaneous switch between the condensed and dispersed conformations, allowing forisomes to seal the sieve plate pores of injured sieve elements. Recently, three genes encoding forisome components from Medicago truncatula were identified [Medicago truncatula sieve element occlusion 1 (MtSEO1), MtSEO2 and MtSEO3] and MtSEO1 expression was shown to be restricted to immature sieve elements. Here, we present a detailed molecular analysis of the MtSEO2 and MtSEO3 promoters and show, through reverse transcriptase-polymerase chain reaction and reporter-transgenic experiments in M. truncatula roots and tobacco plants, that their expression profiles are comparable to MtSEO1. The impact of these data on the likelihood of MtSEO gene co-regulation by common transcription factors is discussed.
KeywordsMedicago truncatula Forisome Promoter Phloem Immature sieve elements
green fluorescent protein
sieve element occlusion
The technical assistance of Ann-Christin Müller is gratefully acknowledged. This work was partially supported by the BMBF grant 0312014, the Fraunhofer MAVO program and by the VolkswagenStiftung, contract no. I/82 075.
- Behnke HD (1991) Nondispersive protein bodies in sieve elements: a survey and review of their origin, distribution and taxonomic significance. IAWA Bull 12:143–175Google Scholar
- Doyle JJ, Doyle JL (1990) Isolation of plant DNA from fresh tissue. Focus 12:13–15Google Scholar
- Lawton DM (1978b) P-protein crystals do not disperse in uninjured sieve elements in roots of runner bean (Phaseolus multiflorus) fixed in glutaraldehyde. Ann Bot (Lond) 42:353–361Google Scholar
- Noll GA (2005) Molekularbiologische Charakterisierung der Forisome. Doctoral thesis, Justus-Liebig Universität, GießenGoogle Scholar
- Pommerrenig B, Barth I, Niedermeier M, Kopp S, Schmid J, Dwyer RA, McNair RJ, Klebl F, Sauer N (2006) Common plantain. A collection of expressed sequence tags from vascular tissue and a simple and efficient transformation method. Plant Physiol 142:1427–1441. doi: 10.1104/pp. 106.089169 CrossRefPubMedGoogle Scholar
- Schneidereit A, Imlau A, Sauer N (2008) Conserved cis-regulatory elements for DNA-binding-with-one-finger and homeo-domain-leucine-zipper transcription factors regulate companion cell-specific expression of the Arabidopsis thaliana SUCROSE TRANSPORTER 2 gene. Planta 228:651–662. doi: 10.1007/s00425-008-0767-4 CrossRefPubMedGoogle Scholar
- Schwan S, Fritzsche M, Cismak A, Noll GA, Prüfer D, Spohn U, Heilmann A (2007b) Micromechanical measurements on chemo-mechanical protein aggregates. MRS Proc 0975:DD03–DD10Google Scholar