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21.
Anne Hukkanen Liisa Pietikäinen Sirpa Kärenlampi Harri Kokko 《European journal of plant pathology / European Foundation for Plant Pathology》2006,116(3):225-235
Downy mildew disease caused by Peronospora sparsa, also known as ‘dryberry’ disease, is a serious threat to the cultivation of arctic bramble (Rubus arcticus) and boysenberry (Rubus spp. hybrid). A quantitative and sensitive screening method is necessary for the breeding of downy mildew resistant cultivars and for determining efficient disease control methods. A quantitative real-time PCR method using SYBR® Green I fluorescent dye was developed for the analysis of P. sparsa in arctic bramble, other Rubus species and roses. Primers were designed to amplify a P. sparsa specific 94-bp fragment from the internal transcribed spacer region (ITS1) and a 140-bp fragment from a conserved region of plant 5.8S ribosomal DNA, which served as an internal control in the samples. Linear amplification from genomic DNA and control plasmids was achieved with both primers, and even 37 fg of P. sparsa conidial DNA was detected. In the samples collected from the field, quantities as low as 0.2 ppm of P. sparsa DNA in plant DNA were detected, thus enabling the diagnosis of weak and latent infections. Arctic bramble cvs Pima, Mespi and Mesma, all showing distinct foliar symptoms, were tested to assess the relative amount of downy mildew DNA present. The symptoms and the amount of P. sparsa DNA detected correlated only in cv. Pima, indicating that visual inspection of symptoms is not a reliable method for assessing the extent of tissue infection. The number of conidiophores of P. sparsa on in vitro inoculated leaves of two arctic bramble cultivars correlated with the results obtained by real-time PCR. 相似文献
22.
Hukkanen A Kostamo K Kärenlampi S Kokko H 《Journal of agricultural and food chemistry》2008,56(3):1008-1016
The main arctic bramble ( Rubus arcticus) cultivars are susceptible to downy mildew ( Peronospora sparsa), which seriously threatens the cultivation. The efficiency of Aliette, Euparen M, phosphite-containing Phosfik, Phostrol, Farm-Fos-44, and Kaliumfosfiet, as well as Bion was evaluated in the greenhouse. Fewer symptoms and less Peronospora DNA were found in plants treated with Euparen M and Bion, whereas Aliette, Phosfik, and Phostrol gave moderate protection. Three arctic bramble cultivars showed varying susceptibility to P. sparsa. An inexpensive and fast in vitro plate test gave results parallel with those obtained in the greenhouse. Quantitative differences were found in the phenolic profiles of the leaves of different cultivars and in different treatments. Several phenolic compounds were tentatively identified in arctic bramble for the first time, for example, monomeric and oligomeric ellagitannins and galloylglucoses. Negative correlation was found between the amount of P. sparsa DNA and flavonol glycosides and some ellagitannins in the leaves 8 days after inoculation, suggesting a possible role for these phenolics in the defense. 相似文献