TITLE:
Transient expression of the Arabidopsis thaliana callose synthase PMR4 increases penetration resistance to powdery mildew in barley
AUTHORS:
Antje Blümke, Shauna C. Somerville, Christian A. Voigt
KEYWORDS:
Biotic Stress; Callose; Glucan; Fungal Resistance; Plant Defense; Plant Engineering
JOURNAL NAME:
Advances in Bioscience and Biotechnology,
Vol.4 No.8,
August
1,
2013
ABSTRACT: Localized cell wall thickenings, so called papillae, are a common
plant defense response to fungal attack at sites of penetration of the plant
cell. The major constituent of papillae is callose, a (1,3)-β-glucan polymer, which contributes to slowing or blocking the
invading fungal hyphae. In the model plant Arabidopsis thaliana, we could recently show that
the overexpression of PMR4(POWDERY MILDEW RESITANT 4), which encodes a stress induced callose synthase, results
in complete powdery mildew resistance. To evaluate if these findings are also
transferable to monocot crops, we transiently expressed PMR4 under
control of the 35S promoter in leaves of barley (Hordeum vulgare) seedlings, which were subsequently
inoculated with the virulent powdery mildew Blumeria graminis f. sp. hordei. Fusion of the green fluorescent protein (GFP) to PMR4
allowed the identification of successfully transformed barley cells, which
showed an increased penetration resistance to B. graminis compared to control cells that express only GFP.PMR4-GFP localized in a similar pattern at the site of attempted fungal
penetration as observed inA. thaliana, which suggests that similar
transport mechanisms of the callose synthase might exist in dicot and monocot
plants.