A self-fertile mutant of Phalaris produces an S protein with reduced thioredoxin activity
✍ Scribed by Xinmin Li; Jan Nield; David Hayman; Peter Langridge
- Book ID
- 104463602
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 654 KB
- Volume
- 10
- Category
- Article
- ISSN
- 0960-7412
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✦ Synopsis
Gametophytic self‐incompatibility in the Phalaris coerulescens is controlled by two unlinked genes, S and Z. Isolation of the S gene from the pollen of this grass species indicated that the C terminus has significant hemology with thioredoxin H proteins. The protein from the C terminus, expressed in Escherichia coli, exhibits thioredoxin‐like activity. This paper demonstrates that the C terminus of the S protein from an S complete mutant shows significant reduction in thioredoxin activity when compared with the wild‐type form. Both pollen and stigma have lost self‐incompatibility in this mutant. Close examination of the lesions, which were found only in the C terminus of the mutant gene suggests that the substitution of a serine by an arginine is responsible for the reduced enzymatic activity. The association between reduced activity and the loss of the self‐incompatibility provides evidence for a role of thioredoxin activity in the self‐incompatibility reaction of this species.