Silicon induced resistance against powdery mildew of roses caused by Podosphaera pannosa

TY - JOUR

T1 - Silicon induced resistance against powdery mildew of roses caused by Podosphaera pannosa

AU - Shetty, Radhakrishna

AU - Jensen, Birgit

AU - Shetty, Nandini Prasad

AU - Hansen, Michael

AU - Hansen, C.W.

AU - Starkey, Kirsten Rasmussen

AU - Jørgensen, Hans Jørgen Lyngs

PY - 2012/2

Y1 - 2012/2

N2 - Powdery mildew, caused by Podosphaera pannosa, is a very common disease in greenhouse potted roses, resulting in poor marketing value and hence economic losses. Alternatives to chemical control are necessary, and therefore the ability of silicon (Si) applied to roots to control the disease was investigated, as well as the mechanisms behind the observed disease reductions. Four genotypes of miniature potted roses representing different genetic backgrounds and susceptibility to disease were studied. Plants were watered with a nutrient solution containing either 3·6mm Si (100ppm) supplied as K 2SiO 3 (Si+) or no Si (Si-) before inoculation with P. pannosa. Si application increased leaf Si content two- to four-fold compared to control plants. Confocal microscopy showed that Si deposition was larger in Si+ than in Si- plants and that deposition mainly occurred in the apoplast, particularly in epidermal cell walls. Si application delayed the onset of disease symptoms by 1-2days and disease severity was reduced by up to 48·9%. The largest reduction was found in the two most resistant genotypes, which also had the highest increase in Si uptake. The Si-induced disease protection was accompanied by increased formation of papillae and fluorescent epidermal cells (FEC) as well as deposition of callose and H 2O 2, especially at the sites of penetration and in FEC, which are believed to represent the hypersensitive response. Si treatment reduced powdery mildew development by inducing host defence responses and can therefore be used as an effective eco-friendly disease control measure.

AB - Powdery mildew, caused by Podosphaera pannosa, is a very common disease in greenhouse potted roses, resulting in poor marketing value and hence economic losses. Alternatives to chemical control are necessary, and therefore the ability of silicon (Si) applied to roots to control the disease was investigated, as well as the mechanisms behind the observed disease reductions. Four genotypes of miniature potted roses representing different genetic backgrounds and susceptibility to disease were studied. Plants were watered with a nutrient solution containing either 3·6mm Si (100ppm) supplied as K 2SiO 3 (Si+) or no Si (Si-) before inoculation with P. pannosa. Si application increased leaf Si content two- to four-fold compared to control plants. Confocal microscopy showed that Si deposition was larger in Si+ than in Si- plants and that deposition mainly occurred in the apoplast, particularly in epidermal cell walls. Si application delayed the onset of disease symptoms by 1-2days and disease severity was reduced by up to 48·9%. The largest reduction was found in the two most resistant genotypes, which also had the highest increase in Si uptake. The Si-induced disease protection was accompanied by increased formation of papillae and fluorescent epidermal cells (FEC) as well as deposition of callose and H 2O 2, especially at the sites of penetration and in FEC, which are believed to represent the hypersensitive response. Si treatment reduced powdery mildew development by inducing host defence responses and can therefore be used as an effective eco-friendly disease control measure.

U2 - 10.1111/j.1365-3059.2011.02493.x

DO - 10.1111/j.1365-3059.2011.02493.x

M3 - Journal article

SN - 0032-0862

VL - 61

SP - 120

EP - 131

JO - Plant Pathology

JF - Plant Pathology

IS - 1

ER -