| All previous plant myosin research has been done using dicotyledons. In this study, we used molecular biological techniques to understand myosin function in several monocotyledonous plants. A myosin gene clone ( pamy1) was identified from orchid (Phalaenopsis amabilis 'Hanben') pollen mother cells, meiotic prophase I pollen, meiotic telophase II pollen, mature pollen and orchid leaf tissue as well. There were different levels of pamy1 myosin gene expression during orchid pollen development. At least five myosin genes were present in orchid genome. Four myosin gene clones, acmy1, acmy2, acmy3 and acmy4, were identified from onion (Allium cepa L.) mature pollen, whereas nine myosin gene clones, acmy1, acmy4, acmy 5, acmy6, acmy7, acmy8, acmy9, acmy10 and acmy11, were isolated from the inner epidermis of onion bulb scales. Except for acmy2 and acmy6 which belong to myosin class II, the other clones belong to myosin class XI. In orchid pollen, the inner epidermis of onion bulb scales, onion roots, shallot roots, corn roots and iris roots, the immunofluorescence staining detected by the polyclonal antibody against plant myosin XI displayed a punctate pattern. In onion pollen mother cells, the immunofluorescence staining was associated with the plasma membrane and the nucleus. In onion mature pollen, the immunofluorescence staining revealed a crescent structure on the side edge of biconcave pollen. Myosin XI is associated with the vesicles and the membranous organelles, but is not associated with the nuclei, plastids/chloroplasts and mitochondria. The results demonstrate that myosin genes in monocotyledonous plants are diverse and myosins play an important role in pollen development and cytoplasmic streaming. |
