Correlation between lack of receptacle growth in response to auxin and accumulation of a specific polypeptide in a strawberry (Fragaria ananassa Duch.) variant genotype

Abstract

Receptacle growth in strawberry (Fragaria ananassa Duch. cv. Ozark Beauty) occurred after either pollination or auxin treatment. In a strawberry variant genotype (Washington State University Selection No. 12/13), pollination did not lead to receptacle growth but application of α-naphthaleneacetic acid (NAA) at anthesis resulted in normal receptacle growth. The receptacles of Ozark Beauty retained their ability to respond to auxin at least up to 36 days after anthesis. However, delay of auxin application to the receptacles of the variant genotype resulted in decreased auxin-responsive growth and auxin application after the 10th day of anthesis led to very little growth. The loss of auxin-responsive growth of the receptacle of the variant genotype was not associated with any loss of auxin binding activity of receptacle membranes. If auxin was not supplied to the receptacles of the variant genotype at anthesis, the receptacles did not grow and a polypeptide of 52,000 M_r accumulated. Application of NAA to the receptacles of the variant genotype at anthesis or on the fifth day after anthesis resulted in the growth of the receptacle and the 52,000 Mr polypeptide did not accumulate. Application of NAA to the receptacles of the variant genotype on the 10th or the 15th day after anthesis led to very little growth of the receptacle and the 52,000 M_r polypeptide accumulated to high levels. These results suggested a correlation between the lack of receptacle growth in response to auxin and accumulation of the 52,000 M_r polypeptide.