CHARACTERIZATION OF THE YELLOW-PIGMENT GENES OF ERWINIA-HERBICOLA

A 6.7kb DNA fragment containing the pigment genes of Erwinia herbicola Eho13 has been cloned into Escherichia coli. These genes were chromosomally encoded in E. herbicola. The entire DNA fragment could be divided into at least three regions. Deletions in Region I resulted in a non-pigmented phenotype, a deletion in Region II resulted in a pink/yellow phenotype, deletions in Region III resulted in either a pink or a non-pigmented phenotype. Tn1000 insertions in the same regions, however, gave different phenotypes. Insertions in Region II produced a pink phenotype. Insertions in Region III resulted in either a light-yellow or a non-pigmented phenotype. Minicell studies showed that the 6.7kb DNA fragment encoded at least five proteins (50kDa, 42kDa, 36kDa, 35kDa and 34kDa). A 2.7kb HindIII deletion in Region I caused the disappearance of these proteins, suggesting that this 2.7kb fragment may play a regulatory role in pigment synthesis. Our results also showed that a 4.1kb EcoRV fragment consisted of Region I and a part of Region II complemented a pink/yellow clone of Eho10 (pHL545), suggesting that the pigments of Eho13 and Eho10 were probably similar or identical.