A new leaf blight disease of oat (Avena sativa) was observed in many oat fields in Huan county, Gansu Province of China, during 2018–2019. Typical symptoms appeared as yellow necrotic and water-soaked lesions. The lesions developed from tip to base of leaves and eventually resulted in leaf withering. Disease incidence on plants (leaves) was approximately 36%–100%. A gram-negative bacterium was isolated from the necrotic lesions of all samples. Coupled with multigene sequence (16S rRNA and gyrB gene) analyses, Biolog Gen III MicroStation, morphological, physiological, and biochemical characterization identified the pathogen as Pantoea agglomerans. Pathogenicity tests by wounding and injection inoculations in the greenhouse established that P. agglomerans could induce typical symptoms as observed in the field. The infection rate in leaves was 44%–71% after 14 days. In addition, host range tests showed that P. agglomerans could infect other plant hosts, including Sorghum sudanense, Medicago sativa, Fagopyrum esculentum, Setaria italica, and Zea mays. This is the first report of P. agglomerans causing bacterial leaf blight disease (LBD) on oat in China. The current study can provide a foundation for the prevention of this disease in the future. 相似文献
Coriander (Coriandrum sativum) is a medicinal and aromatic plant. From November 2017 to March 2020, leaf blight disease on coriander plants was frequently observed in commercial coriander cultivated fields of Haikou, Sanya and Wanning City, Hainan Province, China. Leaves with symptoms showed irregular chlorotic to dark brown necrotic lesions at the edges of leaves, and the leaves were curled and covered with a layer of grey mould. Based on morphological characteristics, pathogenicity testing and concatenated sequences of the internal transcribed spacer region (ITS), actin (ACT) and translation elongation factor-1α (TEF) genes, the pathogen was identified as Cladosporium tenuissimum. Untargeted metabolomes of the coriander leaves were analysed by gas chromatography-mass spectrometry (GC-MS). Score plots of principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) showed clear discrimination between infected and control treatments. The levels of l -threonic acid, hexadecanoic acid and myo-inositol in the control treatment were 3.45-, 1.81- and 2.44-fold, respectively, those in the infected treatment. To our knowledge, this is the first report of C. tenuissimum causing coriander leaf blight disease in China. Furthermore, this study indicates that C. tenuissimum infection of coriander causes a significant decrease in l -threonic acid, hexadecanoic acid and myo-inositol levels, indicating that these metabolites may be involved in the plant's response to coriander leaf blight disease. 相似文献
To establish a quality evaluation system of the fruit quality of pear, 15 evaluation indicators of 9 main cultivars of pear (Pyrus spp.) in North China were analyzed. Analysis of variance (ANOVA), correlation analysis (CA), principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used to form a comprehensive evaluation model and select the characteristic indicators of the fruit quality. All of the 15 evaluation indicators showed significant differences from the results of ANOVA (P?<?0.05) among different cultivars. The values for coefficient of variation (CV) among 15 evaluation indicators ranged from 1.46% to 326.38%. There were different degrees of correlations between the evaluation indicators based on the results of CA. PCA was used to remove the overlapped information between the indicators, and then there were new variables with less information, so that the principal component comprehensive model was established. The rank of the 9 cultivars based on comprehensive scores of the fruit quality was listed as follows: ‘Mili’?>?‘Xuehua’?>?‘Hongxiangsu’?>?‘Daguoxing’?>?‘Yali’?>?‘Huangguan’?>?‘Yuluxiang’?>?‘Hongxiaoli’?>?‘Anli’. By combining HCA and principal component comprehensive model, titratable acid content, sugar-acid ratio, h* and fruit shape index were selected to be the characteristic indicators for the evaluation of the fruit quality of the main cultivars of pear in North China.
New Forests - Plant functional traits have been shown to vary with environmental conditions. However, we lack empirical data on how plant functional traits of different plant life forms respond to... 相似文献
New Forests - Qinghai spruce (Picea crassifolia Kom.) forests play a key role in the carbon sequestration in the Qilian Mountains, Northwestern China. Carbon sequestration is closely related to... 相似文献