FIG. 3.

(a) Root colonization (%) by P. dissotocum (a1) and P. oligandrum (a2), assessed by plate counting. The values reported are means for eight samples collected each month. The signed rank test indicates preferential colonization of the control plants by P. dissotocum (P = 0.029) and a more extensive colonization of the inoculated plants by P. oligandrum (P = 0.0000123). (b) Root colonization by P. dissotocum (b1) and P. oligandrum (b2), assessed by real-time PCR. DNA quantities correspond to amounts of Pythium DNA (fg) per unit of tomato DNA (ng). Median values are represented on the graphs (medians are suitable markers for dissymmetrical distributions). P. oligandrum DNA quantities were higher on inoculated than on control plants (signed rank test; P = 0.0000123), and those of P. dissotocum on control and inoculated plants were not significantly different.