Summary
Detached pistils from inbred lines of Brassica oleracea L. var alboglabra were fed with okadaic acid (OA), an inhibitor of serine/threonine protein phosphatases, via the transpiration stream. Following self-pollination, pollen tubes were observed to have grown into or through the styles of pistils treated with OA, but not those of untreated controls. Treatment with 1 μM OA was sufficient to completely overcome self-incompatibility (SI) in an inbred line homozygous for the S63 allele, though an OA concentration of 5 μM was required to cause breakdown of SI in an inbred line homozygous for the S29 allele. At the higher concentration used, pollen tube growth was arrested before the pollen tubes reached the ovary, but this effect was also noted in cross-pollinated styles treated in the same manner. These data provide evidence for the involvement of type 1 and/or type 2A protein phosphatases in the Brassica SI signal transduction mechanism.
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Present address after November 1993: Department of Biology, Colorado State University, Fort Collins, Colorado, USA
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Scutt, C.P., Fordham-Skelton, A.P. & Croy, R.R.D. Okadaic acid causes breakdown of self-incompatibility in Brassica oleracea: evidence for the involvement of protein phosphatases in the incompatible response. Sexual Plant Reprod 6, 282–285 (1993). https://doi.org/10.1007/BF00231906
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DOI: https://doi.org/10.1007/BF00231906