Table I.

GO terms differentially represented in pollen grains as compared to vegetative tissues

Relative frequencies of function, process, and component terms at the different levels of the GO trees were compared pairwise in pollen grains, leaves, seedlings, and siliques. For each comparison, genes were classified as either over- or underrepresented in one particular tissue; statistically significant differences between any two tissues were determined by using a two-tailed test for proportion differences (P value < 0.05). The terms for which statistical significance was found in all three pollen-to-vegetative tissue comparisons are shown.

LevelOverrepresented in Pollen (P < 0.05)Underrepresented in Pollen (P < 0.05)
Function Term
    2Transcription regulator
Structural protein
    3Nucleotide bindingTranscription factor
Intracellular transporter
    4Purine nucleotide bindingPeptidase
Transferase, transferring phosphorus-containing groups
Protein kinase
Hydrolase, acting on acid anhydrides
Calcium binding
Translation initiation factor
Small GTPase regulatory/interacting protein
    5Adenyl nucleotide bindingEndopeptidase
Hydrolase, acting on acid anhydrides, in phosphorus-containing anhydridesAspartic-type endopeptidase
Guanyl nucleotide binding
Phosphoric ester hydrolase
P-type ATPase
    6ATP bindingPepsin A
GTP binding
Phosphoric monoester hydrolase
    7Small monomeric GTPase
Protein phosphatase
    8Protein Ser/Thr phosphatase
Process Term
    2Cellular process
    3Cell growth and maintenance
Cell communication
Signal transductionPhotosynthesis, light reactions
Cell organization and biogenesis
    5Protein transportMacromolecule biosynthesis
Intracellular transportProtein biosynthesis
Intracellular signaling cascade
    6Intracellular protein traffic
Protein amino acid dephosphorylation
Small GTPase-mediated signal transduction
Ribonucleotide biosynthesis
Nucleoside triphosphate metabolism
Nucleoside triphosphate biosynthesis
ER-to-Golgi transport
Component Term
    1Cellular component
    3Protein Ser/Thr phosphatase complexIntracellular