马铃薯Y病毒对不同马铃薯品种的致病力

摘要

为明确不同马铃薯Y病毒(PVY)株系对马铃薯的影响及危害,采用PVYN∶O、PVYN-Wi、PVYNTN-NW(SYRⅠ)和PVYNTN NW(SYRⅡ)株系分离物人工侵染马铃薯,并通过透射电子显微镜观察经PVY侵染后马铃薯植株细胞的超微结构.结果表明,敏感品种更适用于PVY病毒致病力鉴定,敏感品种‘克新13’和‘克新18’对PVY不同分离物的反应强烈,差异显著,而‘必加2号’对4个PVY分离株均表现耐病,虽然细胞内均出现叶绿体变形、单层膜小囊泡和典型的风轮状内含体,但症状只表现为不同程度的花叶.同时,发现PVYS-W致病力较弱,侵染后,4个马铃薯品种均出现花叶症状,细胞内部产生多膜结构、风轮状内含体,引起敏感品种‘克新13’和‘克新18’细胞变形、叶绿体变形和髓鞘样结构;PVYNTN-NW致病力最强,感病的‘克新13’和‘克新18’植株受害症状明显加重,且植株早衰、细胞破坏严重,有些死亡较快的植株甚至未产生特征性内含体结构;PVYN∶O致病力中等,植株受害症状和超微结构变化也介于PVYN-Wi和PVYNTN-NW之间.不同马铃薯品种对PVY病毒的感病程度有较大差异,‘兴加2号’为耐病品种.%Potato virus Y (PVY) is one of the most common and worldwide destructive viruses that affects potato production.To unveil the effects and the pathogenicity of different strains of PVY in different potato varieties,four natural recombinant PVY strains including PVYN∶O,PVYN Wi,PVYNTN-NW (SYR-Ⅰ) and PVYNTN-NW(SYR-Ⅱ) were mechanically inoculated onto four potato varieties.In addition to the visual foliar and tuber symptom observations,the ultrastructure and cellular morphology changes were also monitored by electron microscopy.Generally,PVYN Wi caused mild symptoms (mainly mosaic) on all varieties,whereas the remaining strains caused severe foliar and/or tuber symptoms.The variety ‘ Xingjia 2’ exhibited mild foliar symptoms compared with other varieties especially ‘ Kexin 13’ and ‘Kexin 18’ upon infection with different strains of PVY.Interestingly,in spite of the fact that PVYN-Wi only caused mild symptoms in all varieties,it induced cellular morphological in varyingdegrees and changed ranging from pinwheel formation in ‘Xingjia 2’ to pinwheel formation,chloroplast degradation,membrane proliferation and cell deformation in ‘Kexin 18’.The pathogenicity of PVYNTN-NW (SYR-Ⅰ and SYR-Ⅱ) was the strongest in the tested strains,which not only caused serve foliar symptoms in ‘ Kexin 13’,‘ Kexin 18 ’ and ‘ Favorita ’,but also incited necrotic ringspots in tubers of at least two varieties (i.e.,‘Kexin 13’ and ‘Xingjia 2’).The pathogenicity of PVYN∶O falled between PVYN-Wi and PVYNTN-NW,and it caused intermediate level of symptoms in plants and intermediate degree of changes in ultrastructure.This study illuminated the interactions between different PVY strains and different potato varieties in both whole-plant and ultrastructural levels,thus this provided insights for better management of this destructive virus in potato crops.