广州地区十字花科蔬菜花叶病第三类病原病毒的鑑定

THE IDENTITY OF A THIRD VIRUS CAUSING THE MOSAIC DISEASE OF CRUCIFEROUS VEGETABLES IN CANTON

广州地区十字花科蔬菜花叶病第三类病原病毒的物理性质与TMV基本相似:失毒温度86—90℃之間,寄主体外存活期限37个月以上,稀释終点1:10000—50000之間。本病毒易由液汁接触传染,可由斜纹夜盜蛾、菜粉蝶和甘蓝夜蛾的2—3龄幼虫、普通紅蜘蛛以及中国菟絲子传染。但不能由桃蚜、蘿卜蚜、黃条跳(虫甲)成虫以及感病蔬菜的种子传染。在含新鮮病菜組織的土壤中移植蔬菜,可引起部分蔬菜感染发病。本病毒的寄生范围較广。在供試植物20科49屬93个种和品种中,能侵染十字花科、茄科、菊科、藜科、莧科、車前草科和石竹科植物等7科18屬54种和品种。交互保护試驗結果,TMV(毒株23号)对本病毒只有小部分的保护作用。但根据周家熾、田波等試驗結果認为本病毒与TMV有一定的血清学关系,因此暫把此病毒列入TMV类羣中,作为一个远缘的毒株。

It was reported previously by the authors that the mosaic disease of cruciferous vegetables in Canton may be caused by the turnip mosaic virus as well as by the cucumber mosaic virus. It was found that disease may be caused by a third virus which was infrequently isolated from the cruciferous vegetables during the course of the present study. The virus is identified as a strain of TMV on the basis of antiserum reaction, physical properties and some other properties are considered to be closely related to those of the Chinese rape mosaic virus No. 3 (YMV_3) reported by Wei et al. in Nanking and to the Chinese cabbage mosaic virus No. 3 (Kwuting No. 3) reported by Chiu et al. in Peking. This virus causes mosaic symptom on most species of cruciferous vegetables; Iocal Iesions on Nicotiana glutinosa, turkey tobacco, white burley tobacco and other species of Nicotiana; and Iocal Iesions, systemic mosaic and then systemic ring-spot symptoms on common tobacco (N. tabacum var. Connecticut Havana 38). The physical properties of this virus are similar to those of TMV: thermal death point—86-90℃, aging period—more than 37 months, and dilution end point—1: 10000-50000. The present virus was transmitted easily by sap inoculation, and less easily by larvae of white fly (Pieris rapae Linn.), army worm (Prodenia litura Fab.), and lopper worm (Phytometra sp.); by adults of red mite (Tetranychus telaxina Linn.); and by dodder (Cuscutus chinensis Linn.). It was not transmitted by false cabbage aphid (Rhopalosiphum pseudobrassicae Dav.), peach aphid (Myzus persicae Sulz.) and striped flea-beetle (Phyllotreta vittata Fab.) The virus was not transmitted by seeds of diseased cruciferous plants. Soil mixed with fresh residues of diseased plants occasionally induced infection of transplanted plants. Host range tests were made on 93 plant species or varieties belonging to 49 genera of 20 families. Among them, 54 plant species or varieties belonging to 18 genera of 7 families (including Cruciferae, Solanaceae, Compositae, Chenopodiaceae, Amaranthaceae, Coryophyllaceae and Plantaginaceae) were found to be susceptible. Cross-protection tests show that the present virus is protected to low degree by the ordinary TMV, indicating that the two viruses, although they belong to the same group (i.e., TMV group), are not very closely related.