讨论了基于高光谱成像技术光谱及纹理特征在识别早期柑橘黄龙病中的应用。使用一套近地高光谱成像系统采集了176枚柑橘叶片的高光谱图像作为实验样品,其中健康叶片60枚,黄龙病叶片60枚,缺锌叶片56枚。手工选取每幅叶片高光谱图像的病斑...讨论了基于高光谱成像技术光谱及纹理特征在识别早期柑橘黄龙病中的应用。使用一套近地高光谱成像系统采集了176枚柑橘叶片的高光谱图像作为实验样品,其中健康叶片60枚,黄龙病叶片60枚,缺锌叶片56枚。手工选取每幅叶片高光谱图像的病斑位置作为样品感兴趣区域（regions of interest,ROI）,计算其平均光谱反射率,并以此作为样品的反射光谱,光谱范围为396～1 010nm。样品光谱分别经过主成分分析（PXA）及连续投影算法（SPA）进行数据降维,再结合最小二乘支持向量机（LS-SVM）分类器建立分类模型。相比原始光谱,由PCA选取的前四个主成分及SPA选取的一组最佳波长组合（630.4,679.4,749.4和899.9 nm）建立的模型拥有更好的分类识别能力,其对三类柑橘叶片平均预测准确率分别为89.7%和87.4%。同时,从被选四个波长的每幅灰度图像中提取6个灰度直方图的纹理特征以及9个灰度共生矩阵的纹理特征再次构建分类模型。经SPA优选的10个纹理特征值进一步提高了分类效果,对三类柑橘叶片的识别正确率达到了100%,93.3%和92.9%。实验结果表明,同时包含光谱信息及空间纹理信息的高光谱图像在柑橘黄龙病的识别中显示了很大的潜力。展开更多
Huanglongbing (HLB) or citrus greening is currently the most important citrus disease, caused by the bacterium </span><i><span style="font-family:Verdana;">Candidatus</span></i>...Huanglongbing (HLB) or citrus greening is currently the most important citrus disease, caused by the bacterium </span><i><span style="font-family:Verdana;">Candidatus</span></i><span style="font-family:Verdana;"> Liberibacter asiaticus (</span><i><span style="font-family:Verdana;">C</span></i><span style="font-family:Verdana;">Las). The impossibility of isolating it causes understanding its pathogenic mechanisms to be a complicated task. Recent studies identified 16 proteins with the signal peptide needed to be secreted in the plant and cause the disease. The present study aims to perform a bioinformatic analysis of these proteins with the function prediction approach by gene ontology (GO) and the detection of conserved domains. It was observed that of the 16 proteins analyzed not all are found in different infective strains reported in the literature. The GO analysis allowed us to relate different proteins with the biological process of energy and pathogenic activity, especially CLIBASIA_03315 and CLIBASIA_05115, respectively. The domain analysis allowed the observation of a </span></span><i><span style="font-family:Verdana;">β</span></i><span style="font-family:""><span style="font-family:Verdana;">-CA domain, tentatively related to the damage caused to the chloroplast and a PAAR domain associated with the T6SS secretory system. Our results provide information on the possible function of potential pathogenicity effectors in </span><i><span style="font-family:Verdana;">C</span></i><span style="font-family:Verdana;">Las.展开更多
Citrus huanglongbing（HLB） has become a major disease and limiting factor of production in citrus areas that have become infected. The destruction to the affected citrus industries has resulted in a tremendous increa...Citrus huanglongbing（HLB） has become a major disease and limiting factor of production in citrus areas that have become infected. The destruction to the affected citrus industries has resulted in a tremendous increase to support research that in return has resulted in significant information on both applied and basic knowledge concerning this important disease to the global citrus industry. Recent research indicates the relationship between citrus and the causal agent of HLB is shaped by multiple elements, in which host defense responses may also play an important role. This review is intended to provide an overview of the importance of HLB to a wider audience of plant biologists. Recent advances on host-pathogen interactions, population genetics and vectoring of the causal agent are discussed.展开更多
基金The Citrus Research and Development Council,USA,National Natural Science Foundation for Young Scholars of China(31301240)
文摘讨论了基于高光谱成像技术光谱及纹理特征在识别早期柑橘黄龙病中的应用。使用一套近地高光谱成像系统采集了176枚柑橘叶片的高光谱图像作为实验样品,其中健康叶片60枚,黄龙病叶片60枚,缺锌叶片56枚。手工选取每幅叶片高光谱图像的病斑位置作为样品感兴趣区域（regions of interest,ROI）,计算其平均光谱反射率,并以此作为样品的反射光谱,光谱范围为396～1 010nm。样品光谱分别经过主成分分析（PXA）及连续投影算法（SPA）进行数据降维,再结合最小二乘支持向量机（LS-SVM）分类器建立分类模型。相比原始光谱,由PCA选取的前四个主成分及SPA选取的一组最佳波长组合（630.4,679.4,749.4和899.9 nm）建立的模型拥有更好的分类识别能力,其对三类柑橘叶片平均预测准确率分别为89.7%和87.4%。同时,从被选四个波长的每幅灰度图像中提取6个灰度直方图的纹理特征以及9个灰度共生矩阵的纹理特征再次构建分类模型。经SPA优选的10个纹理特征值进一步提高了分类效果,对三类柑橘叶片的识别正确率达到了100%,93.3%和92.9%。实验结果表明,同时包含光谱信息及空间纹理信息的高光谱图像在柑橘黄龙病的识别中显示了很大的潜力。
文摘Huanglongbing (HLB) or citrus greening is currently the most important citrus disease, caused by the bacterium </span><i><span style="font-family:Verdana;">Candidatus</span></i><span style="font-family:Verdana;"> Liberibacter asiaticus (</span><i><span style="font-family:Verdana;">C</span></i><span style="font-family:Verdana;">Las). The impossibility of isolating it causes understanding its pathogenic mechanisms to be a complicated task. Recent studies identified 16 proteins with the signal peptide needed to be secreted in the plant and cause the disease. The present study aims to perform a bioinformatic analysis of these proteins with the function prediction approach by gene ontology (GO) and the detection of conserved domains. It was observed that of the 16 proteins analyzed not all are found in different infective strains reported in the literature. The GO analysis allowed us to relate different proteins with the biological process of energy and pathogenic activity, especially CLIBASIA_03315 and CLIBASIA_05115, respectively. The domain analysis allowed the observation of a </span></span><i><span style="font-family:Verdana;">β</span></i><span style="font-family:""><span style="font-family:Verdana;">-CA domain, tentatively related to the damage caused to the chloroplast and a PAAR domain associated with the T6SS secretory system. Our results provide information on the possible function of potential pathogenicity effectors in </span><i><span style="font-family:Verdana;">C</span></i><span style="font-family:Verdana;">Las.
基金the United States citrus industry and various funding agencies for their commitment and continued support for HLB research
文摘Citrus huanglongbing（HLB） has become a major disease and limiting factor of production in citrus areas that have become infected. The destruction to the affected citrus industries has resulted in a tremendous increase to support research that in return has resulted in significant information on both applied and basic knowledge concerning this important disease to the global citrus industry. Recent research indicates the relationship between citrus and the causal agent of HLB is shaped by multiple elements, in which host defense responses may also play an important role. This review is intended to provide an overview of the importance of HLB to a wider audience of plant biologists. Recent advances on host-pathogen interactions, population genetics and vectoring of the causal agent are discussed.
