Alteration of the self-incompatibility phenotype in Brassica by transformation of the antisense SLG gene

Self-incompatible (SI) Brassica rapa (syn. B. campestris) was transformed with an antisense SLG gene by using SLG(8) cDNA isolated from the B. campestris Ss homozygote. Two transformed lines were obtained and analyzed. Northern blot and Western blot analyses revealed that endogenous SLG and SRK were greatly reduced of the transcriptional and translational levels in the transformant. Pollination experiments confirmed that their SI phenotype had broken down. In addition, the progeny with the antisense SLG gene, resulting from self- or cross-pollination of the transgenic plant, also showed the self-compatible phenotype. The breakdown of ST in the tranformants was due to the change in property of the stigma and not of the pollen. These results provide strong evidence that SLG and/or SRK is implicated in the pollen-stigma recognition of SI and that they act only as stigmatic factors.