Changes in Protein Patterns and Protein Synthesis during Anther Development in Brassica oleracea

Abstract

Summary To study male gametophyte development in Brassica oleracea L., the various stages of microspores and pollen in fresh anthers were assessed with the use of fluorescent dyes and by cytological observations. Developmental variations in SDS-PAGE protein patterns of anthers and pollen grains were then analysed from the late vacuolate microspore stage to the end of the pollen-maturation period. Total protein staining and concanavalin A-binding glycoprotein detection showed that a specific set of developmental polypeptides appears during the tricellular pollen stages. Protein synthesis was studied by [ 31 S] methionine incorporation, SDS-PAGE, fluorography. Two periods of protein synthetic activity were detected: the first one corresponding to the microspore and bicellular pollen stages; the second one corresponding to the mid, late, mature tricellular pollen stages. During this second period, new polypeptides were synthesized and most of them could be correlated with the developmental polypeptides that appeared in total and Con A-binding protein patterns. These results suggest the occurrence of a metabolic reorientation after the second pollen mitosis, at the time of sperm cell maturation. The biochemical data are discussed in terms of diploid and haploid genome expression.