CHANGES OF OVULE PROTEINS DURING EARLY FIBER DEVELOPMENT IN A NORMAL AND A FIBERLESS LINE OF COTTON (GOSSYPIUM-HIRSUTUM L)

Total protein was extracted from ovules during the temporal developmen t of cotton fiber initiation and compared by 2-D PAGE. Comparisons wer e made between two cultivars of cotton (Gossypium hirsutum L.), i.e., a ''normal'' fiber-producing line (DPL 5690) and a fiberless line (SL 1-7-1). In all, 37 protein differences were found, and these were cate gorized into 5 groups. The groups have been designated either V-, D-, S-, B-, or E-types: V for varietal differences, which are proteins fou nd at all ages but occurring in only one line; D for developmental dif ferences unique to DPL 5690; S for developmental differences unique to SL 1-7-1; B (before anthesis) are proteins found in both lines that d iminish postanthesis; and E (embryogenesis) are proteins found in both lines that accumulate postanthesis. Six V-type proteins have been ide ntified, with five of these specific to the fiberless line. Sixteen D- type proteins were identified in which 14 (88%) accumulated postanthes is. Of the 14 proteins, 5 proteins were specific to the normal line. T he data on the 5 proteins indicate that they are involved in early eve nts of fiber development. Eight: S-type proteins were identified; howe ver, unlike D-type proteins, only 2 (25%) accumulate postanthesis. Thr ee B-type proteins were identified, each with the same molecular mass. Four E-type proteins were identified and, along with the B-type, are (probably) involved in ovule growth or associated with the changes tak ing place in the ovule at fertilization. Overall, these data provide a catalogue of 37 proteins, potentially important to future studies in fiber and ovule developmental physiology.