Sequence of a Plastocyanin cDNA From Wheat and the Use of the Gene Product to Determine Serologically Tissue Degradation after Infection with Pseudocercosporella herpotrichoidesa

Pseudocercosporella herpotrkhoides, the causal agetit of the eyespot disease of wheat, induces lesions at the stetn bases, in degraded tissue a specific protein (Pc) cannot more be detected whereas it is abundantly produced in the green tissue showing no disease symptotns. In plant satnples including the stem bases, the amount of protein Pc is therefore correlated with the degree of tissue degradation. A serological test (ELiSA) was developed for the quantitative determination of the protein. ELISA readings can be used as estimates of disease severity. By sequence analysis, Pc was identified as plastocyanin. Based on the nucleic acid sequence, wheat pre-plastocyanin consists of a transit peptide of 61 amino acids and a tnature peptide of 97 residues. Comparison of the nucleotide sequences of plastocyanin of wheat and barley showed homology of 93.7%.