Fig 1.
Diagram of in vitro chemotaxis assay.
(A) Grid for the analysis of nematode preferential orientation on the medium; each segment of the grid was given a score for the presence (1) or absence of nematode tracks (0); (B) Calculation of the chemotaxis factor (Cf).
Fig 2.
Effects of root exudates on M. incognita egg hatch.
HR, MR and T represent the root exudates from three tomato strains: Baliya (highly resistant), RS2 (moderately resistant) and L-402 (highly susceptible), respectively. Total number of J2 in each root exudate (sterilized water as control) was calculated at 8d after starting the assay. Relative suppression rate (%) = (number of J2 in sterilized water—number of J2 in root exudate) / number of J2 in sterilized water × 100. Each bar represents the mean, and error bars indicate standard error of the mean from three replicates. Capital and lower case letters indicate significant group differences at the levels of 0.01 and 0.05, respectively.
Fig 3.
Effects of root exudates on corrected mortality of M. incognita J2.
HR, MR and T represent the root exudates from three tomato strains: Baliya (highly resistant), RS2 (moderately resistant) and L-402 (highly susceptible), respectively. The mortality of J2 in each root exudate (sterilized water as control) was assessed by the eyelash needle stimulus method at 24 h and 48 h after starting the assay. Corrected mortality rate (%) = (mortality rate of J2 in root exudate—mortality rate of J2 in sterilized water) / (1—mortality rate of J2 in sterilized water) ×100. Each bar represents the mean, and error bars indicate standard error of the mean from three replicates. Capital and lower case letters indicate significant group differences at the levels of 0.01 and 0.05, respectively.
Table 1.
Effects of root exudates on chemotaxis of M. incognita J2 at WA plate.
Table 2.
Component identified from tomato plant root exudates.
Fig 4.
Effects of simulated components on relative suppression of M. incognita egg hatch.
A, 2,6-Di-tert-butyl-p-cresol; B, L-ascorbyl-2,6-dipalmitate; C, dibutyl phthalate; D, dimethyl phthalate; 0.5,0.5 mmol·L-1; 1,1 mmol·L-1; 2,2 mmol·L-1. Total number of J2 in each treatment (1.0% ethanol as control) was calculated at 8d after starting the assay. Relative suppression rate (%) = (number of J2 in control—number of J2 in treatment) / number of J2 in control × 100. Each bar represents the mean, and error bars indicate standard error of the mean from three replicates. Capital and lower case letters indicate significant group differences at the levels of 0.01 and 0.05, respectively.
Fig 5.
Effects of simulated components on corrected mortality of M.incognita J2.
A, 2,6-Di-tert-butyl-p-cresol; B, L-ascorbyl-2,6-dipalmitate; C, dibutyl phthalate; D, dimethyl phthalate; 0.5,0.5 mmol·L-1; 1,1 mmol·L-1; 2,2 mmol·L-1. The mortality of J2 in each treatment (1.0% ethanol as control) was assessed by the eyelash needle stimulus method at 24 h and 48 h after starting the assay. Corrected mortality rate (%) = (mortality rate of J2 in treatment—mortality rate of J2 in control) / (1—mortality rate of J2 in control) ×100. Each bar represents the mean, and error bars indicate standard error of the mean from three replicates. Capital and lower case letters indicate significant group differences at the levels of 0.01 and 0.05, respectively.
Table 3.
Effects of four simulated components on chemotaxis of M. incognita J2 at WA plate.
Fig 6.
Effects of simulated components on disease resistance to M. incognita in cv. L-402.
A, 2,6-Di-tert-butyl-p-cresol; B, L-ascorbyl-2,6-dipalmitate; C, dibutyl phthalate; D, dimethyl phthalate; CK: 1.0% ethanol; 0.5,0.5 mmol·L-1; 1,1 mmol·L-1; 2,2 mmol·L-1. Each bar represents the mean, and error bars indicate standard error of the mean from three replicates. Capital and lower case letters indicate significant group differences at the levels of 0.01 and 0.05, respectively.