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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
2008-10-3
pubmed:abstractText
Molecular events occurring in the plant apoplast contribute to important developmental and defense responses. To define the secretome of Medicago, we used suspension cultures to isolate and identify secreted proteins as a first step to determining their functions. Proteins in the extracellular medium of the suspension cultures were examined using SDS-PAGE, tandem mass spectrometry (MALDI-TOF/TOF) and bioinformatics tools. There were 39 proteins identified in the cultures derived from M. sativa, M. truncatula 2HA (an embryogenic line), and M. truncatula sickle (an ethylene-insensitive mutant). N-Terminal secretion signals were detected in 34 proteins and five other proteins were predicted to be secreted via a nonclassical (ER-independent) route. All samples possessed defense related proteins including pathogenesis related (PR) proteins. The glycoprotein, SIEP1L, was found only in M. sativa. Three secreted proteinases were identified in M. truncatula, including a serine carboxypeptidase detected only in 2HA. Some proteins were unique to a cell culture line. Quantitative real time RT-PCR was used to determine mRNA expression of selected genes corresponding to proteins found only in 2HA or sickle or in both. The results correlate well with the proteomic data. For instance, a GDSL-lipase gene known to be regulated by ethylene was found only in 2HA but not in the ethylene insensitive mutant. Similarly, the PR1a protein, expressed from a well recognized ethylene-regulated gene, was found in 2HA but not sickle. These experiments indicate that the suspension culture systems established here are useful to avoid contamination from cytoplasmic proteins and to identify secreted proteins in Medicago, and should have application in other plant systems.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
1535-3893
pubmed:author
pubmed:issnType
Print
pubmed:volume
7
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4508-20
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Characterization of the secretome of suspension cultures of Medicago species reveals proteins important for defense and development.
pubmed:affiliation
Australian Research Council Centre of Excellence for Integrative Legume Research, Genomic Interactions Group, Research School of Biological Sciences, Australian National University, Canberra ACT 2601, Australia.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't