The mucilage proteome of maize (Zea mays L.) primary roots.

Department of Plant Nutrition, China Agricultural University, Beijing, PR China.
Journal of Proteome Research (Impact Factor: 5.06). 06/2010; 9(6):2968-76. DOI: 10.1021/pr901168v
Source: PubMed

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.

  • [Show abstract] [Hide abstract]
    ABSTRACT: The significance of root exudates as belowground defense substances has long been underestimated, presumably due to being buried out of sight. Nevertheless, this chapter of root biology has been progressively addressed within the past decade through the characterization of novel constitutively secreted and inducible phytochemicals that directly repel, inhibit, or kill pathogenic microorganisms in the rhizosphere. In addition, the complex transport machinery involved in their export has been considerably unraveled. It has become evident that the profile of defense root exudates is not only diverse in its composition, but also strikingly dynamic. In this review, we discuss current knowledge of the nature and regulation of root-secreted defense compounds and the role of transport proteins in modulating their release.
    Trends in Plant Science 12/2013; · 11.81 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Heterosis is the superior performance of heterozygous F1-hybrid plants compared to their homozygous genetically distinct parents. Seminal roots are embryonic roots that play an important role during early maize (Zea mays L.) seedling development. In the present study the most abundant soluble proteins of 2-4 cm seminal roots of the reciprocal maize F1-hybrids B73xMo17 and Mo17xB73 and their parental inbred lines B73 and Mo17 were quantified by label-free LC-MS/MS. In total, 1,918 proteins were detected by this shot-gun approach. Among those, 970 were represented by at least two peptides and were further analyzed. Eighty-five proteins displayed non-additive accumulation in at least one hybrid. The functional category protein metabolism was the most abundant class of non-additive proteins represented by 27 proteins. Within this category 16 of 17 non-additively accumulated ribosomal proteins showed high or above high parent expression in seminal roots. These results imply that an increased protein synthesis rate in hybrids might be related to the early manifestation of hybrid vigor in seminal roots. SIGNIFICANCE: In the present study a shot-gun proteomics approach allowed for the identification detection of 1,917 proteins and analysis of 970 seminal root proteins of maize that were represented by at least 2 peptides. The comparison of proteome complexity of reciprocal hybrids and their parental inbred lines indicate an increased protein synthesis rate in hybrids that may contribute to the early manifestation of heterosis in seminal roots.
    Journal of proteomics 04/2013; · 5.07 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Arabinogalactan proteins (AGPs) are among the most intriguing sets of macromolecules, specific to plants, structurally complex, and found abundantly in all plant organs including roots, as well as in root exudates. AGPs have been implicated in several fundamental plant processes such as development and reproduction. Recently, they have emerged as interesting actors of root–microbe interactions in the rhizosphere. Indeed, recent findings indicate that AGPs play key roles at various levels of interaction between roots and soilborne microbes, either beneficial or pathogenic. Therefore, the focus of this review is the role of AGPs in the interactions between root cells and microbes. Under- standing this facet of AGP function will undoubtedly improve plant health and crop protection.
    Trends in Plant Science 05/2013; · 11.81 Impact Factor