Article

Proteomic analyses ofOryza sativa mature pollen reveal novel proteins associated with pollen germination and tube growth

Key Laboratory of Photosynthesis & Environmental Molecular Physiology, Research Center for Molecular & Developmental Biology, Institute of Botany, Chinese Academy of Sciences, Beijing, PR China.
PROTEOMICS (Impact Factor: 3.97). 04/2006; 6(8):2504-29. DOI: 10.1002/pmic.200401351
Source: PubMed

ABSTRACT As a highly reduced organism, pollen performs specialized functions to generate and carry sperm into the ovule by its polarily growing pollen tube. Yet the molecular genetic basis of these functions is poorly understood. Here, we identified 322 unique proteins, most of which were not reported previously to be in pollen, from mature pollen of Oryza sativa L. ssp japonica using a proteomic approach, 23% of them having more than one isoform. Functional classification reveals that an overrepresentation of the proteins was related to signal transduction (10%), wall remodeling and metabolism (11%), and protein synthesis, assembly and degradation (14%), as well as carbohydrate and energy metabolism (25%). Further, 11% of the identified proteins are functionally unknown and do not contain any conserved domain associated with known activities. These analyses also identified 5 novel proteins by de novo sequencing and revealed several important proteins, mainly involved in signal transduction (such as protein kinases, receptor kinase-interacting proteins, guanosine 5'-diphosphate dissociation inhibitors, C2 domain-containing proteins, cyclophilins), protein synthesis, assembly and degradation (such as prohibitin, mitochondrial processing peptidase, putative UFD1, AAA+ ATPase), and wall remodeling and metabolism (such as reversibly glycosylated polypeptides, cellulose synthase-like OsCsLF7). The study is the first close investigation, to our knowledge, of protein complement in mature pollen, and presents useful molecular information at the protein level to further understand the mechanisms underlying pollen germination and tube growth.

0 Followers
 · 
156 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: As the female reproductive part of a flower, pistil consists of ovary, style and stigma, and is a critical organ for the process from pollen recognition to fertilization and seed formation. Previous studies on pollen-pistil interaction mainly focused on gene expression changes with comparative transcriptomics or proteomics method. However studies on protein post-translational modifications are still lacking. Here we report a phosphoproteomic study on mature pistil of rice. Using IMAC enrichment, HILIC fraction and high-accuracy MS instrument (TripleTOF 5600), 2,347 of high confident (Ascore≥19, p≤0.01) phosphorylation sites corresponding to 1,588 phosphoproteins were identified. Among them, 1,369 phosphorylation sites within 654 phosphoproteins were newly identified; 41 Serine Phosphorylation motifs which belong to 3 groups: proline-directed, basophilic and acidic motifs were identified after analysis by motif-X; 201 genes whose phosphopeptides were identified here showed tissue-specific expression in pistil based on information mining of previous microarray data. The Mass spectra data have been deposited to the PRIDE with identifier PXD000923. This study will help us to understand the pistil development and pollination on post-translational level.This article is protected by copyright. All rights reserved
    Proteomics 10/2014; 14(20). DOI:10.1002/pmic.201400004 · 3.97 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Germination of pollen grains is a crucial step in plant reproduction. However, the molecular mechanisms involved remain unclear. We investigated the role of PECTIN METHYLESTERASE48 (PME48), an enzyme implicated in the remodeling of pectins in Arabidopsis thaliana pollen. A combination of functional genomics, gene expression, in vivo and in vitro pollen germination, immunolabeling and biochemical analyses was used on wild-type and Atpme48 mutant plants. We showed that AtPME48 is specifically expressed in the male gametophyte and is the second most expressed PMEs in dry and imbibed pollen grains. Pollen grains from homozygous mutant lines displayed a significant delay in imbibition and germination in vitro and in vivo. Moreover, numerous pollen grains showed two tips emerging instead of one in the wild-type. Immunolabeling and FT-IR analyses showed that the degree of methylesterification of the homogalacturonan (HG) was higher in pme48-/- pollen grains. In contrast, the PME activity was lower in pme48-/- partly due to a reduction of PME48 activity revealed by zymogram. Interestingly, the wild-type phenotype was restored in pme48-/- with the optimum germination medium supplemented with 2.5 mM calcium chloride suggesting that in the wild-type pollen, the weakly methylesterified HG is a source of Ca2+ necessary for pollen germination. Although pollen specific PMEs are traditionally associated with pollen tube elongation, this study provides strong evidence that PME48 impacts the mechanical properties of the intine wall during maturation of the pollen grain which, in turn, influence pollen grain germination.
    Plant physiology 02/2015; DOI:10.1104/pp.114.250928 · 7.39 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Sample preparation is key to the success of proteomics studies. In the present study, two sample preparation methods were tested for their suitability on the mature, recalcitrant leaves of six representative perennial plants (grape, plum, pear, peach, orange, and ramie). An improved sample preparation method was obtained: Tris and Triton X-100 were added together instead of CHAPS to the lysis buffer, and a 20% TCA-water solution and 100% precooled acetone were added after the protein extraction for the further purification of protein. This method effectively eliminates nonprotein impurities and obtains a clear two-dimensional gel electrophoresis array. The method facilitates the separation of high-molecular-weight proteins and increases the resolution of low-abundance proteins. This method provides a widely applicable and economically feasible technology for the proteomic study of the mature, recalcitrant leaves of perennial plants.
    PLoS ONE 07/2014; 9(7):e102175. DOI:10.1371/journal.pone.0102175 · 3.53 Impact Factor

Full-text (2 Sources)

Download
68 Downloads
Available from
May 20, 2014