Identification And Variety Of Leaf Spot Caused By Alternaria On Vegetables In China

Alternaria spp. affected a wide range of host plants. It is one of the most important pathogens of crops, vegetables and human. A lot of diseases on vegetables were caused by Alternaria, such as tomato early blight, Altemaria black spot of Crucifers and purple leaf blotch on Liliaceae. In this study, we investigated the epidemic situation of leaf spots caused by Alternaria on vegetables and collected samples in China. The pathogens were identificated based on morphological, pathogenicity test and molecular characteristics.1. Two new recorded host diseases caused by Alternaria in China were discovered. The diseases on Solanum muricatum and Abelmoschus esculentus discovered from Gansu and Beijing. The pathogens were identificated as Altemaria alternata through morphological and molecular method.2.557 samples of leaf spots caused by Alternaria form 14 Provinces were collected, include 32 hosts from Solanaceae, Cucurbitaceae and Cruciferae, Liliaceae. Leaf spot on vegetables of Solanaceae are distributed among Inner Mongolia, Beijing, Gansu Province, Sinkiang Province, Tianjin, Shandong Province, Guangxi Province, Ningxia Province, Shanxi Province; leaf spot on vegetables of Cucurbitaceae are distributed among Hunan Province, Hubei Province, Gansu Province, Shandong Province, Henan Province, Beijing; leaf spot on vegetables of Cruciferae are distributed among Hebei Province, Gansu Province, Liaoning Province, Guizhou Province, Hunan Province, Hubei Province, Tibet, Yunnan Province, Ningxia Province, Sichuan Province, Shanxi Province, Guangdong Province, Sinkiang; leaf spot on vegetables of Liliaceae are distributed among Shanxi Province, Tianjing, Shandong Province, Mongolia, Beijing, Hebei Province, Hunan Province.3. Eight pathogens were identificated in this study, there are A. alternata, A. solani, A. cucumerina, A. brassicicola, A. ponicola, A. melongenae, A. brassicae and A. porrio The hosts of A. alternata were among the vegetables of Solanaceae, Cruciferae and Cucurbitaceae in this study. Leaf spot on vegetables of Solanaceae were caused by A. melongenae and A. solani; leaf spot on vegetables of Cucurbitaceae were caused by A. peponicola and A. cucumerina; leaf spot on vegetables of Cruciferae were caused by A. brassicicola and A. brassicae; leaf spot on vegetables of Liliaceae were caused by A. porri in this study.4. Pathogens were study by phylogeny analysis. Phylogeny tree were constructed based on ITS and Alt a 1. Isolates had a near relationship in the phylogeny trees based on ITS. Different species cluster together in the phylogeny trees based on Alt a 1 in this study. Pathogens isolated from Cucurbitaceae were divided into three sub-groups, it is associated with geographical origin of the isolate. Pathogens isolated from Solanaceae were divided into two sub-groups (A. alternata group, A. solani group).In this study, the occurrence of leaf spot caused by Alternaria on vegetables were invested systemically for the first time in China. We confirmed the Category of Alternaria spot and confirmed the pathogens and distribution in China. This study provided theoretical basis for Prevention and similar research.