Leaf ascorbic acid level - Is it really important for ozone tolerance in rice?

► A rice TOS17 mutant for a GDP-D-mannose-3′,5′-epimerase gene was examined under high ozone stress. ► Leaf ascorbate level was decreased by 20 to 30 percent compared to the wild-type. ► Mutants exhibited a different steady state of the ascorbate-glutathione cycle. ► Low ascorbate level negatively affected rice yields at high ozone concentrations. ► Mutant plants had altered lignin and phenolics concentration of mature straw.