Expanding nematode-induced syncytia: the role of expansins.
Parasitism of the cyst nematode Heterodera schachtii is characterised by the formation of syncytial feeding structures within the host root. Syncytia are formed by the fusion of root cells accompanied by local cell wall degradation, fusion of protoplasts and hypertrophy. Expansins are cell wall-loosening proteins involved in growth and cell wall disassembly. In this study we analysed whether members of the expansin gene family are specifically and developmentally regulated during syncytium formation in roots of Arabidopsis thaliana. By screening of a cDNA library of syncytia for expansin transcripts several AtEXPAs and one AtEXPB were found. In a semi-quantitative RT-PCR and a Genechip analysis AtEXPA3, AtEXPA6, AtEXPA8, AtEXPA10 and AtEXPA16 were found to be up-regulated specifically in syncytia but not to be transcribed in surrounding root tissue. Histological analyses including analysis of promoter::GUS lines and in situ RT-PCR supported the specific expression pattern. Among the specifically expressed genes, AtEXPA3 and AtEXPA16 turned out to be of special interest as they are shoot-specific in un-infected plants. We conclude that a number of expansins take part in cell growth and cell wall disassembly during syncytium formation.
Wieczorek
Krzysztof
K
Institute of Plant Protection; Department of Applied Plant Sciences and Plant Biotechnology; University of Natural Resources and Applied Life Sciences; Vienna, Austria.
Grundler
Florian Mw
FM
Commun Agric Appl Biol Sci. 2005;70(1):51-60
16363359
Planta. 2006 Jun;224(1):155-62
16395582
Mol Plant Microbe Interact. 2000 Oct;13(10):1121-9
11043473
Plant Cell. 1992 Nov;4:1425-33
11538167
Plant Physiol. 2000 Aug;123(4):1399-414
10938357
Plant Cell. 2002 Dec;14(12):3237-53
12468740
Plant J. 2005 Nov;44(3):447-58
16236154
Plant Physiol Biochem. 2004 Sep;42(9):709-16
15474376
Nature. 2000 Sep 21;407(6802):321-6
11014181
Plant Cell. 2001 Oct;13(10):2241-55
11595799
Plant Cell. 1997 Sep;9(9):1661-71
9338967
Plant Mol Biol. 2004 May;55(3):311-4
15604683