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The symplasmic transport of protein and RNAs has emerged as a novel mechanism of cell to cell communication in plant. This movement can occur in selective or a non-selective way between neighbouring cells, tissues or in whole plant. The symplasmic transport is under control both during plant development and in response to environmental conditions. The knowledge about RNAs and proteins that move from cell to cell through plasmodesmata and in the whole plant though phloem is still growing. The transport of mRNA such genes like KN1 or CmNCAP1, has been also described. Recently, it has been shown that phloem sap of some plants species contains an endogenous population of small RNAs corresponding to si- and miRNAs. Additionally, it has been identified 27 kDa phloem protein CmPSRP1 which binds selectively small, single stranded RNAs which penetrate from companion cells to sieve tubes of phloem system. Recent advances have also increased our understanding of mechanism of spreading through the plant a mobile silencing signal associated with PTGS (Post Transcriptional Gene Silencing). This signal is transported as 21 nt siRNA which is amplificated every 10–15 cells and then delivered to neighboring cells.

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The Editorial Board
Andrzej Łukaszyk - przewodniczący, Zofia Bielańska-Osuchowska, Szczepan Biliński, Mieczysław Chorąży, Aleksander Koj, Włodzimierz Korochoda, Leszek Kuźnicki, Aleksandra Stojałowska, Lech Wojtczak

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Katedra i Zakład Histologii i Embriologii Uniwersytetu Medycznego w Poznaniu, ul. Święcickiego 6, 60-781 Poznań, tel. +48 61 8546453, fax. +48 61 8546440, email:

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