Different concentrations of jasmonic acid(JA)and benzothiadiazole(BTH) were sprayed on 2-year-old Rosa rugosa‘Plena’ seedlings. The induced resistance of JA and BTH to Sphaerotheca pannosa(Wallr.) and the changes of...Different concentrations of jasmonic acid(JA)and benzothiadiazole(BTH) were sprayed on 2-year-old Rosa rugosa‘Plena’ seedlings. The induced resistance of JA and BTH to Sphaerotheca pannosa(Wallr.) and the changes of their related physiological indices were investigated. Results showed that JA and BTH treatments had inhibitory impacts on S. pannosa infection. The optimal concentration of JA and BTH was 0.5 mmol/L for the disease-resistance induction of the leaves, its inductive effect was up to 66.36% for BTH and 54.49% for JA. Our results confirmed that exogenous JA and BTH significantly improved R. rugose ‘Plena’ resistance to S. pannosa. When treated with JA and BTH, activities of the three defense enzymes(POD, PPO, and PAL) increased significantly.Contents of total phenolics, flavonoids, and lignin also increased significantly. It is inferred from these results that exogenous JA and BTH could improve the resistance of R.rugose ‘Plena’ to S. pannosa through enhancing activities of the defensive enzymes and accumulation of secondary metabolites in the leaves.展开更多
Identification of powdery mildew pathogens on melon（Cucumis melo） is important for melon breeding and diseaseresistant germplasm selection. In this study, a powdery mildew pathogen that infected melon plants in Heil...Identification of powdery mildew pathogens on melon（Cucumis melo） is important for melon breeding and diseaseresistant germplasm selection. In this study, a powdery mildew pathogen that infected melon plants in Heilongjiang Province, China, was investigated in terms of host identification, morphological characteristics and phylogenetic relationships. The morphological characteristics of the pathogen were observed at five phases in the life cycle： germinating conidia, primary germ tube, hyphae, conidiophores, and colonization. The conidia were elliptical, colorless, catenulate, and the average length was 29.07 μm and average width was 17.82 μm. One ascus and eight ascospores were produced. DNA was extracted from 0.01 g conidiophores from a strain of powdery mildew pathogen that infected melon. ITS ribosomal DNA region（524 bp） was amplified with the universal ITS1 and ITS4 primers. The nucleotide sequence showed 100% similarity with ITS sequences for three Podosphaera fusca strains obtained from the GenBank database. The identity of the pathogen was confirmed as Sphaerotheca fuliginea. International standard differential hosts were used to identify S. fuliginea strain as 2F race. These results supported the notion that Podosphaera fusca was a synonym of S. fuliginea.展开更多
Seedlings of Yujinxiang melon were used to investigate the effect and inhibitive mechanism of sodium silicate and nanosized silicon oxide on powdery mildew. The results showed that the severity of powdery mildew on me...Seedlings of Yujinxiang melon were used to investigate the effect and inhibitive mechanism of sodium silicate and nanosized silicon oxide on powdery mildew. The results showed that the severity of powdery mildew on melon seedlings was lowered significantly by treatment with either of the two silicon compounds, although the effect of sodium silicate was more powerful than silicon oxide. Application of sodium silicate to the seedlings caused significant increases in the activity of peroxidase (POD) and of β-1,3-glucosidase (GLU), both enzymes are known to be associated with the disease defence systems of plants. SEM-EDX analysis of sodium silicate-treated leaves of the melon seedlings showed an elevated level of silicon deposit at stomata and epidermis. Treatment with nanosized silicon oxide also resulted in a similar increase in silicon deposit, but the treatment did not cause a significant increase in POD activity.展开更多
The researches through Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) indicated that Sphaerotheca pannosa directly intrude in the place of concave of rose leaves,form filiform haustorium...The researches through Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) indicated that Sphaerotheca pannosa directly intrude in the place of concave of rose leaves,form filiform haustorium in the epidermal cells,absorb the nutrient and water,and destory the internal structure of mitochondrions,etc.when epidermal cells are filled with filiform haustorium.展开更多
Powdery mildew, which called Sphaerotheca phaseoli in Latin, is one of the major diseases of mungbean （Vigna radiata L.） worldwide, causing up to 50% yield losses. Most mungbean varieties grown in Thailand are susce...Powdery mildew, which called Sphaerotheca phaseoli in Latin, is one of the major diseases of mungbean （Vigna radiata L.） worldwide, causing up to 50% yield losses. Most mungbean varieties grown in Thailand are susceptible to the disease, therefore, new resistant varieties are highly desirable. Three resistant mungbean lines, V4718, V4758 and V4785, were identified from the AVRDC collection. In this study, the authors compared the resistance levels among these 3 lines and tested the allelic relationship among these resistance genes. Three crosses, V4718 × V4758, V4718 × V4785 and V4758 × V4785, were made and the F1 hybrids were selfed to generate the F2 populations and crossed to a susceptible variety, CN72 to generate the F1 × S populations. In the F1 × S and F2 populations, the resistance segregated in a ratio of 3 Resistant （R）：I Susceptible （S） and 15R：IS, respectively for all three crosses. These results indicate that a single dominant gene confers resistance to powdery mildew in each resistant line and these resistance genes are non-allelic. The authors are currently transferring these resistance genes into commercial varieties to provide durable resistance to powdery mildew.展开更多
基金supported by the Science Foundation of Heilongjiang Province of China(No.QC2014C012)the Fundamental Research Funds for the Central Universities(NO.2572016CA11)
文摘Different concentrations of jasmonic acid(JA)and benzothiadiazole(BTH) were sprayed on 2-year-old Rosa rugosa‘Plena’ seedlings. The induced resistance of JA and BTH to Sphaerotheca pannosa(Wallr.) and the changes of their related physiological indices were investigated. Results showed that JA and BTH treatments had inhibitory impacts on S. pannosa infection. The optimal concentration of JA and BTH was 0.5 mmol/L for the disease-resistance induction of the leaves, its inductive effect was up to 66.36% for BTH and 54.49% for JA. Our results confirmed that exogenous JA and BTH significantly improved R. rugose ‘Plena’ resistance to S. pannosa. When treated with JA and BTH, activities of the three defense enzymes(POD, PPO, and PAL) increased significantly.Contents of total phenolics, flavonoids, and lignin also increased significantly. It is inferred from these results that exogenous JA and BTH could improve the resistance of R.rugose ‘Plena’ to S. pannosa through enhancing activities of the defensive enzymes and accumulation of secondary metabolites in the leaves.
基金Supported by the Earmarked Fund for Modern Agro-industry Technology Research System(CARS-26-02)the National Natural Science Foundation(31000917)Heilongjiang Excellent Young Funding(JC200712)
文摘Identification of powdery mildew pathogens on melon（Cucumis melo） is important for melon breeding and diseaseresistant germplasm selection. In this study, a powdery mildew pathogen that infected melon plants in Heilongjiang Province, China, was investigated in terms of host identification, morphological characteristics and phylogenetic relationships. The morphological characteristics of the pathogen were observed at five phases in the life cycle： germinating conidia, primary germ tube, hyphae, conidiophores, and colonization. The conidia were elliptical, colorless, catenulate, and the average length was 29.07 μm and average width was 17.82 μm. One ascus and eight ascospores were produced. DNA was extracted from 0.01 g conidiophores from a strain of powdery mildew pathogen that infected melon. ITS ribosomal DNA region（524 bp） was amplified with the universal ITS1 and ITS4 primers. The nucleotide sequence showed 100% similarity with ITS sequences for three Podosphaera fusca strains obtained from the GenBank database. The identity of the pathogen was confirmed as Sphaerotheca fuliginea. International standard differential hosts were used to identify S. fuliginea strain as 2F race. These results supported the notion that Podosphaera fusca was a synonym of S. fuliginea.
文摘Seedlings of Yujinxiang melon were used to investigate the effect and inhibitive mechanism of sodium silicate and nanosized silicon oxide on powdery mildew. The results showed that the severity of powdery mildew on melon seedlings was lowered significantly by treatment with either of the two silicon compounds, although the effect of sodium silicate was more powerful than silicon oxide. Application of sodium silicate to the seedlings caused significant increases in the activity of peroxidase (POD) and of β-1,3-glucosidase (GLU), both enzymes are known to be associated with the disease defence systems of plants. SEM-EDX analysis of sodium silicate-treated leaves of the melon seedlings showed an elevated level of silicon deposit at stomata and epidermis. Treatment with nanosized silicon oxide also resulted in a similar increase in silicon deposit, but the treatment did not cause a significant increase in POD activity.
文摘The researches through Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) indicated that Sphaerotheca pannosa directly intrude in the place of concave of rose leaves,form filiform haustorium in the epidermal cells,absorb the nutrient and water,and destory the internal structure of mitochondrions,etc.when epidermal cells are filled with filiform haustorium.
文摘Powdery mildew, which called Sphaerotheca phaseoli in Latin, is one of the major diseases of mungbean （Vigna radiata L.） worldwide, causing up to 50% yield losses. Most mungbean varieties grown in Thailand are susceptible to the disease, therefore, new resistant varieties are highly desirable. Three resistant mungbean lines, V4718, V4758 and V4785, were identified from the AVRDC collection. In this study, the authors compared the resistance levels among these 3 lines and tested the allelic relationship among these resistance genes. Three crosses, V4718 × V4758, V4718 × V4785 and V4758 × V4785, were made and the F1 hybrids were selfed to generate the F2 populations and crossed to a susceptible variety, CN72 to generate the F1 × S populations. In the F1 × S and F2 populations, the resistance segregated in a ratio of 3 Resistant （R）：I Susceptible （S） and 15R：IS, respectively for all three crosses. These results indicate that a single dominant gene confers resistance to powdery mildew in each resistant line and these resistance genes are non-allelic. The authors are currently transferring these resistance genes into commercial varieties to provide durable resistance to powdery mildew.
