Immunocytochemical and biochemical studies of the mobilisation of storage oil-bodies and proteins in germinating cotyledons of oilseed rape, Brassica napus
✍ Scribed by Denis J Murphy; Ian Cummins; Angray S Kang
- Publisher
- John Wiley and Sons
- Year
- 1989
- Tongue
- English
- Weight
- 875 KB
- Volume
- 48
- Category
- Article
- ISSN
- 0022-5142
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✦ Synopsis
Seeds of Brassica napus L cu Mikado contain about 25% W J W protein in addition to 40-50 % w/w storage oil. About SO "/, of' the seed protein is the legumin-like neutral protein, crucifirin, and afurther 20 :d is the small basic protein, napin. The only other major seed protein (20% of total) is a polypeptide of' apparent molecular inass ( M , ) 19 000 200, which is associuted with the membranes of the storage oil-bodies. The purification of this protein and preparation of' monospecific antibodies have recently been reported. The kinetics of protein arid oil mobilisation and the subcellular distribution of' the M , 19 000 oil-body protein have been studied by techniques including sodium dodecyl sulphate~~polyacrylamide gel electrophoresis (SDS-PAGE), gas-liquid chromatography (GLC), sucrose density gradient fiuctionation, arid electron microscopy-immunocytochemistry. The results show that the mobilisution of' the storage products of rapeseed occurs in at least three distinct phases: ( I ) a lay phase of' 10-15 h, (2) breukdown of cruciferin and napin from 12 h until duy 3, (3) breakdown of storuge oil and oil-body membranes fiom day 2 until day 7. The M , 19000 protein was loculised on oil-body membranes in early stages of germination but was later associated with a light membrane )action, which probably contained oil-body ghosts. Relatitlely little dijerence in the kinetics of' the mobilisation of storage oils and proteins was jound whether seedlings were grown in the light or in the dark. The implications of' these results ,for the mechanism of storage oil mobilkation in oilseeds are discussed.