Abundant Type III Lipid Transfer Proteins in Arabidopsis Tapetum Are Secreted to the Locule and Become a Constituent of the Pollen Exine

摘要: Lipid transfer proteins (LTPs) are small secretory in plants with defined lipid-binding structures for possible lipid exocytosis. Special groups of LTPs unique to the anther tapetum abundant, but their functions unclear. We studied a special group LTPs, type III Arabidopsis (Arabidopsis thaliana). Their transcripts were restricted tapetum, levels peaking at developmental stage maximal pollen-wall exine synthesis. constructed an LTP-Green Fluorescent Protein (LTP-GFP) plasmid, transformed it into wild-type plants, and monitored LTP-GFP developing anthers confocal laser scanning microscopy. appeared was secreted via endoplasmic reticulum-trans-Golgi network machinery locule. It then moved microspore surface remained as component exine. Immuno-transmission electron microscopy native LTP confirmed observations. The vivo association not observed non-type or structurally modified exine-defective mutant plants. RNA interference knockdown individual produced no observable phenotypes. two microscopy-observable morphologic changes intine underneath (presumably consequence by transmission microscopy) pollen susceptible dehydration damage. Overall, we reveal novel pathway which bound nonbound precursors from become constituents; this explains need plentiful incorporate abundant