Sharp eyespot, caused by Rhizoctonia cerealis, is a destructive disease in
wheat (Triticum aestivum L.). In Arabidopsis, certain cinnamyl alcohol
dehydrogenases (CADs) are known to be related to monolignol synthesis and in
plant response to bacterial pathogens. However, little is known about CADs
in wheat defense. A research team from the Chinese Academy of Agricultural
Sciences, led by Wei Rong, isolated a wheat CAD gene, TaCAD12 and studied
its defense role in wheat.

Transcript levels of TaCAD12 in sharp eyespot-resistant wheat lines were
significantly higher compared to the gene's transcript levels in susceptible
lines. Analysis revealed that TaCAD12 protein is an authentic CAD enzyme and
possesses catalytic efficiencies towards both coniferyl aldehyde and sinapyl
aldehyde.

A TaCAD12 knockdown in wheat plants significantly repressed the plants'
resistance to sharp eyespot, while TaCAD12 overexpression enhanced
resistance of the transgenic wheat. Furthermore, certain defense genes and
monolignol biosynthesis-related genes were also upregulated in the
TaCAD12-overexpressing wheat plants, but down-regulated in TaCAD12-silencing
plants.

These results suggest that TaCAD12 positively contributes to resistance
against sharp eyespot through regulation of the expression of certain
defense genes.



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