title: The mucilage proteome of maize (Zea mays L.) primary roots.
abstract: Maize (Zea mays L.) root cap cells secrete a large variety of compounds including proteins via an amorphous gel structure called mucilage into the rhizosphere. In the present study, mucilage secreted by primary roots of 3-4 day old maize seedlings was collected under axenic conditions, and the constitutively secreted proteome was analyzed. A total of 2848 distinct extracellular proteins were identified by nanoLC-MS/MS. Among those, metabolic proteins (approximately 25%) represented the largest class of annotated proteins. Comprehensive sets of proteins involved in cell wall metabolism, scavenging of reactive oxygen species, stress response, or nutrient acquisition provided detailed insights in functions required at the root-soil interface. For 85-94% of the mucilage proteins previously identified in the relatively small data sets of the dicot species pea, Arabidopsis, and rapeseed, a close homologue was identified in the mucilage proteome of the monocot model plant maize, suggesting a considerable degree of conservation between mono and dicot mucilage proteomes. Homologues of a core set of 12 maize proteins including three superoxide dismutases and four chitinases, which provide protection from fungal infections, were present in all three mucilage proteomes investigated thus far in the dicot species Arabidopsis, rapeseed, and pea and might therefore be of particular importance.
authors.affiliation: Department of Plant Nutrition, China Agricultural University, Beijing, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Ma
authors.forename: Nils
authors.initials: N
authors.lastname: Muthreich
authors.forename: Chengsong
authors.initials: C
authors.lastname: Liao
authors.forename: Mirita
authors.initials: M
authors.lastname: Franz-Wachtel
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schütz
authors.forename: Fusuo
authors.initials: F
authors.lastname: Zhang
authors.forename: Frank
authors.initials: F
authors.lastname: Hochholdinger
authors.forename: Chunjian
authors.initials: C
authors.lastname: Li
mesh_terms: D053858:Metabolic Networks and Pathways; D010449:Peptide Mapping / Q000379:methods*; D010940:Plant Proteins / Q000737:chemistry* / Q000145:classification; D018518:Plant Root Cap / Q000737:chemistry*; D010944:Plants; D020543:Proteome / Q000737:chemistry*; D040681:Structural Homology, Protein; D003313:Zea mays / Q000737:chemistry* / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D020543:Proteome