Transgenic carrots with enhanced resistance against two major pathogens, Erysiphe heraclei and Alternaria dauci

In vitro assay indicated that the human lysozyme has lytic activity against phytopathogenic fungi and bacteria. A human lysozyme gene was placed under control of the constitutive CaMV 35S promoter and the resulting expression plasmid was introduced into two cultivars (cv.) of carrot, Kurodagosun (K5) and Nantes Scarlet (NS), by Agrobacterium tumefaciens-mediated method. Seven and fourteen transgenic plants of cv. K5 and cv. NS were regenerated, respectively, and the obtained transgenic carrots of T0 generation was tested for disease resistance against Erysiphe heraclei, a pathogenic fungi causing powdery mildew. Among the tested lines, the transgenic plant No. 12-1 and 8-1 of cv. NS showed a fairly strong resistance against E. heraclei. The strong disease resistance was also confirmed in T1 generation. Disease resistance against another pathogen of leaf blight, Alternaria dauci, were also tested using T1 transgenic lines. Significant enhanced resistance was observed in the No. 12-1 of cv. NS. Accumulation of synthesized human lysozyme protein was observed in this line, a finding consistent with observed disease resistance. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.