Effect of the triazine herbicides Goltix and Igran on cell wall degradation by some fungi

Abstract

Fifteen-day-old tomato and cotton hypocotyls were susceptible to degradation by the three fungi Aspergillus fumigatus, Fusarium oxysporum f.sp. lycopersici, and Fusarium oxysporum f.sp. vasinfectum. The last two fungi cause tomato and cotton wilts in Egypt. Addition of various concentrations (50–1200 ppm) of Goltix (4-amino-3-methyl-6-phenyl-1,2,4-triazine-5 (4H)-one(IUPAC)) inhibited the tomato cell wall degradation by the tested fungi except its pathogen, while the doses (50–1200 ppm) of Igran (4-ethylamino-2-tert-butylamino-6-methylthio-5-triazine) inhibited tomato cell wall degradation by the three fungi. On the other hand, the addition of various concentrations of Goltix to cotton cell wall culture increased the susceptibility of the cell wall to the degrading enzymes of the three fungi, while Igran inhibited the degradation by the two Fusarium species. The data also emphasized the presence of xylanase, arabanase, mannanase, galactanase, and cellulase enzymes in both tomato and cotton cell wall cultures of the tested fungi. Higher doses of either Goltix or Igran (800 and 1200 ppm) completely inhibited the activation of arabanase, xylanase, and mannanase, while cellulase and galactanase were less sensitive to the applied herbicide doses.