LIGHT AND DEVELOPMENTAL REGULATION OF THE ANP-CONTROLLED ANTHOCYANIN PHENOTYPE OF BEAN PODS

In the presence of the dominant allele of the Anp gene, bean pods pres ent a purple-mottled phenotype. The purple pigmentation is variable fr om cell to cell in the pod epidermal layer and develops as a random mo saic. Three anthocyanidins, delphinidin, petunidin and malvidin, are i nvolved in this purple pigmentation. Anthocyanins accumulated in vacuo les; anthocyanoplasts and cristal bodies were also observed occasional ly. A developmental switch is a prerequisite for anthocyanin accumulat ion in the pods. This does not occur before day 4 after pollination an d is controlled by light in competent pods. mRNAs for PAL, CHS, CHI, D FR and UFGT are induced in the pods, indicating that the general antho cyanin biosynthetic pathway is well conserved at both the biochemical and molecular levels in this species. mRNA steady-state level studies of PAL and CHS suggest that the light regulation occurs at the transcr iptional level.