title: Pollination modulates expression of the PPAL gene, a pistil-specific beta-expansin.
abstract: Using differential screening we isolated a pistil-specific cDNA clone corresponding to a 1.2 kb mRNA and encoding a 32.5 kDa protein. The amino acid sequence shared similarity with that of group-I grass pollen allergens, which are known to have expansin activity. This clone, which later showed to share homology also with beta-expansins, was named PPAL. The PPAL mRNA was specifically expressed in the secretory zone of the stigma and in the epidermal layer of the placenta. The accumulation level of the transcript increased during pollination, and the protein was secreted in the stigmatic exudate of the tobacco flower. We suggest here that PPAL is a new expansin, acting as a cell-wall-loosening agent during pollination.
authors: Plant Genetic Systems, Gent, Belgium.
authors: Mario
authors: M
authors: Pezzotti
authors: Richard
authors: R
authors: Feron
authors: Celestina
authors: C
authors: Mariani
mesh_terms: D000595:Amino Acid Sequence; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D018514:Plant Structures / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D011058:Pollen / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014026:Nicotiana / Q000235:genetics / Q000502:physiology
chemical_list: D018076:DNA, Complementary; D010940:Plant Proteins; D012333:RNA, Messenger; C095825:expansin protein, plant