Fig. 5.

Pathogenicity of VdLs17, VdATMT-021, VdATMT-V47, VdATMT-136, and VdATMT-235. Lettuce cultivar PI 251246 was inoculated by soilless Verticillium assay using conidial suspension (5 × 10⁶) of the mutants and wild-type strain VdLs17. Part of images was captured using CLSM. a, c, g, k, o The cultures phenotype during growth on potato dextrose agar. b Plant inoculated with VdLs17 showing symptoms of vascular wilt disease 21 days after inoculation. d Conidia of VdATMT-021 were showing delayed germination on the lateral roots. e Cross section of main root showing no colonization of VdATMT-021 mutant-inoculated plant, 3 weeks after inoculation. f Vascular discoloration was not observed in ATMT-021 mutant-inoculated plant root system. h Conidia of the VdATMT-V47 mutant were trying to germinate on the lateral roots, 2 weeks after inoculation. i Cross section of main root showing no colonization of VdATMT-V47 mutant-inoculated plant, 3 weeks after inoculation. j Vascular discoloration was not observed in VdATMT-V47 mutant-inoculated plant root system. l Mutant VdATMT-136 showing less colonization on lateral root, 2 weeks after inoculation. m Cross section of main root showing less colonization of VdATMT-136 in the xylem of the plant. n Less vascular discoloration was observed in ATMT-136 mutant-inoculated root system. p Intense colonization of VdATMT-235 on lateral root system, 2 weeks after inoculation. q Cross section of main root showing intense colonization of VdATMT-235 in the xylem of the plant. r Vascular discoloration of the taproot of the plant inoculated with VdATMT-235. d, h, l, p Scale bars = 100 μm; e, i, m, q Scale bars = 50 μm. Red and white arrowheads indicate the site of root colonization and vascular discoloration