FANG Ke-Feng’s research while affiliated with Wuhan University and other places

The presence of mosaicism in the organization of concanavalin agglutinin (Con A) binding sites on murine egg cells was first reported 30 year ago. This discovery has triggered extensive studies into the roles of glycoproteins in gamete interactions in animals. This report comprises the first account of the existence of the mosaicism in higher plants. The distribution of Con A binding sites on both egg cells and central cells of tobacco (Nicotiana tabacum) was found to be polar and apparently determined by the location of the nucleus of the cell. On central cells, Con A binding sites were distributed on the section of the plasma membrane surface near the nucleus. By contrast, the binding sites on egg cells were concentrated away from the nucleus. Therefore, polarity of the plasma membrane component of female cells was confirmed for the first time. It is proposed that such polarized ConA binding sites could be involved in sperm recognition.

Fluorescein isothiocyanate (FITC) conjugated concanavalin agglutinin (Con A), wheat germ agglutinin (WGA) and soybean agglutinin (SBA) were used as probes to localize their specific receptors on the plasma membrane of generative cells (GCs) isolated from Vicia faba L., Iris tectorium Maxim. and Hippeastrum vittatum Herb. It is a further investigation on possible distributive dynamic of lectin receptors during the developmental process from generative cells to sperm cells. In the present study, all the three lectin receptors were found on the surface of generative cells of V. faba and I. tectorium. However, on generative cells of H. vittatum only Con A and WGA, but not SBA receptors were observed. The same lectin receptors on the generative cells from different species showed various distribution patterns. The distribution of various lectin receptors on the same generative cells also showed different characteristics. Lectin receptors were totally absent on some generative cells of all three investigated species. Polar distribution of lectin receptors was observed on tailed generative cells. The findings offer important clues to investigate sperm cell function and possible sperm dimorphism of surface glycoprotein.