N-glycoproteins specific for different stages of microspore and pollen development in tobacco

Glycoproteins (GPs) specifically linked to stages of microspore and pollen development were identified and characterized by: 1D- and 2D-electrophoresi s, treatment with glycosidases, affinity blotting with lectins ConA, GNA, A AA, WGA, DSA; PNA and RCA, and according to cell location. Most GPs reacted with ConA and GNA and were hydrolyzed with PNGase F and endoglycosidase H, indicating N-linkage of high-mannose and/or hybrid type glycans. Early mic rospores were unique by the occurrence of ConA and AAA binding 50- and 52-k D GPs. Specific for mitotic microspores were cytoplasmic neutral GPs 39 and 92 kD, and membrane GP 98 kD. Maturing pollen was characterized by a new s et of ConA-binding GPs: acidic, membrane GP 38 kD, neutral GPs 51, 66 and 7 5 kD, GP 53 kD separated in IEF into spots with pi 6.8-7.5 and 5.9, and IEF variants of GP 55 kD with pi 6.5-7.5, GPs 48, 59, 70, 83 and 114 kD showed developmental changes in reactivity with various lectins. In contrast to G Ps, no clear qualitative changes were observed in profiles of Coomassie blu e stained proteins during pollen development. The oligosaccharide structure s appeared as important determinants of specificities of GPs associated wit h phases of microspore and pollen development. (C) 1999 Elsevier Science Ir eland Ltd. All rights reserved.