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Root-Specific Expression of Genes for Novel Glycine-Rich Proteins Cloned by Use of an Antiserum against Xylem Sap Proteins of Cucumber

1998; Oxford University Press; Volume: 39; Issue: 12 Linguagem: Inglês

10.1093/oxfordjournals.pcp.a029338

1471-9053

Chiyoko Sakuta, A. Oda, Seiyei Yamakawa, Shinobu Satoh,

Polysaccharides and Plant Cell Walls

Candidate cDNAs for xylem sap proteins (XSPs) were isolated by screening of a cucumber cDNA library prepared from poly(A)+ RNA of cucumber roots with an antiserum raised against the XSPs of cucumber. The patterns of expression of corresponding transcripts and the sequences of the cDNAs were examined. Two cDNAs with a glycine-rich domain in each deduced amino acid sequence and whose transcripts were expressed predominantly in roots were selected for further analysis. Both cDNAs encoded proteins with a putative signal sequence, with similar non-glycine-rich domains at the amino terminal of the encoded polypeptides. The corresponding mRNAs accumulated concurrently with the formation of adventitious roots from cuttings of cucumber hypocotyls and the development of vascular tissues, and strong expression of the mRNAs was detected in the root-hair zone of tap roots. These data suggest that the production of the two novel glycine-rich proteins, which are putative XSPs, might be associated with the functions of the vascular tissues in roots.