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. 2010 Apr 9;192(12):3187–3203. doi: 10.1128/JB.01558-09

FIG. 9.

FIG. 9.

The phenotype of an xsuA X. oryzae pv. oryzae mutant is suggestive of deficiency in siderophore uptake. (A) Siderophore production phenotype of an xsuA mutant of X. oryzae pv. oryzae. Strains depicted are BXO43 (wild-type strain), BXO2231 (xsuA1::gusA; a polar mutation), BXO2233 (BXO2231/pAP23; this cosmid contains the xsuA gene but does not contain any intact xss genes), and BXO2234 (BXO2231/pAP15; this cosmid contains the entire xss gene cluster including the xsuA gene). X. oryzae pv. oryzae strains were grown on PSA-CAS medium and 100 μM DP. Siderophore production is evident as a halo around the colonies. (B). An xsuA mutant of X. oryzae pv. oryzae is deficient for growth under iron-limiting conditions. Cell numbers (log values) were estimated in X. oryzae pv. oryzae cultures grown in PS medium and PS-100 μM DP medium at 0 h and after 48 h of growth. (C) An xsuA mutant is unable to use exogenously supplied siderophore. Strains are BXO2211 (xssE1::pK18mob) and BXO2231 (xsuA1::gusA). (D) Genetic complementation restores the ability of an X. oryzae pv. oryzae xsuA mutant to utilize exogenously supplied siderophore. Strains are BXO2231 (xsuA1::gusA), BXO2233 (BXO2231/pAP23), and BXO2234 (BXO2231/pAP15). Cell numbers were estimated in 3 ml of X. oryzae pv. oryzae cultures grown in PS medium, PS-100 μM DP medium, and PS-100 μM DP supplemented with SID (cell-free supernatant of a saturated culture of wild-type X. oryzae pv. oryzae strain BXO43 grown in iron-deficient medium [PS-100 μM DP]) at 0 h and after 48 h of growth. The results from three independent experiments are expressed as means ± standard deviations.