TABLE 2.

Influence of synthetic DON on T. atroviride chitinase gene expression

DON concn (μg/g)a	Glucose oxidase activity (U/ml)b
	ech42-gox		nag1-gox
	P1 alone	P1 plus GZT40	P1 alone	P1 plus GZT40
0	1.19 ac	1.22 a	1.30 a	1.23 a
1	1.20 a	1.20 a	1.09 b	1.04 b
2.5	1.20 a	1.19 a	0.94 c	0.87 c
5	1.19 a	1.21 a	0.79 d	0.79 c

^aDON concentration on malt extract agar plates prior to fungal inoculation.

^bExpression of chitinase genes in T. atroviride strain P1 inoculated alone or together with F. graminearum GZT40 (a mutant which does not produce DON) was quantified after 66 h of growth by using ech42-gox and nag-gox reporter gene fusions. Glucose oxidase activity is expressed in units per milliliter of extraction buffer.

^cThe values are the means of three experiments with six replicates. Means within a column followed by the same letter are not significantly different according to Fisher's protected LSD test (P ≤ 0.05). No significant differences in expression of either chitinase gene were observed at any DON concentration for treatments with and without Fusarium (within-row comparisons).