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Fusarium oxysporum f. sp. lycopersici produces extracellular enzymes known as tomatinase, which degrade the tomato phytoanticipin α-tomatine to less toxic metabolites. Tomatinase gene ( FoToml ) has been found also in certain strains of F. oxysporum belonging to formae speciales nonpathogenic on tomato plants. In the current study, four FoToml -positive strains (#2, #3, #11, and #17) of F. oxysporum belonging to formae speciales different from f. sp. lycopersici and f. sp. radicis - lycopersici were examined for their ability to infect tomato plants. All of the four strains colonized not only the roots and basal stems but also upper stems of tomato plants. One of the four strains, #3 (f. sp. batatas ), was transformed with the β-glucuronidase (GUS) reporter gene. A GUS-marked #3 (#3-GUS) colonized vascular vessels of all tomato cultivars tested differing in the extents of colonization in the stems among the cultivars. Reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed that each FoToml of the four FoToml -positive strains was expressed in the roots and stems of tomato plants, suggesting that FoToml is important for the four strains to survive in tomato plants. To see systemic induction of defense genes in tomato plants inoculated with either #2, #3, #11, or #17, accumulations of transcripts of β-1,3-glucanase and chitinase genes were analyzed. Tomato plants inoculated with #2 or #3 showed enhanced expression of acidic chitinase gene ( Chi 3). Prior inoculation of tomato plants with either #2 or #3 suppressed the vascular wilt of tomato caused by subsequent challenge with F. oxysporum f. sp. lycopersici .

We studied the effects of 2,3-butanedione monoxime (BDM) on the cytoplasmic streaming of Chara corallina and on the motility of myosin prepared from the same plant to examine whether this reagent really affects the plant class XI myosin. It was found that BDM inhibited both cytoplasmic streaming and the motility of myosin at a very similar concentration range (10-100 mM). BDM introduced directly into tonoplast-free cells also inhibited cytoplasmic streaming. These results suggested that effect of BDM on cytoplasmic streaming was exerted through myosin and not through ion channels at least in Chara corallina, though a very high concentration of BDM was required.

The antifungal glycoalkaloid α-tomatine accumulates in tomato plants and may protect plants from fungal infection. Fusarium oxysporum f. sp. lycopersici, the causal agent of vascular wilt of tomato, produces a tomatinase (FoToml) that degrades α-tomatine to the nontoxic compounds tetrasaccharide lycotetraose and tomatidine. Induction of tomatinases and the distribution of FoToml homologs were examined among 30 strains belonging to 16 formae speciales of F. oxysporum. Tomatinase activity was found in 27 strains belonging to 15 formae speciales, but FoToml homologs (>98% sequence identity) were detected in only six strains belonging to four formae speciales. To identify tomatinases other than FoToml, α-tomatine-inducible proteins of another tomato pathogen F. oxysporum f. sp. radicis-lycopersici were analyzed by two-dimensional gel electrophoresis. A protein with a molecular mass of 64 kDa accumulated in the α-tomatine-induced culture filtrates, and the protein had tomatinase activity, degrading α-tomatine to lycotetraose and tomatidine.