Novel resistances to four potyviruses in tuber-bearing potato species, and temperature-sensitive expression of hypersensitive resistance to potato virus Y.

摘要

Novel potyvirus resistance specificities were found in 8 tested wild potato species (clones): hypersensitive resistance (HR) to potato Y potyvirus (PVY) strain groups PVYO in Solanum megistacrolobum and S. polyadenium and PVYN in S. stoloniferum, HRto potato V potyvirus (PVV) in S. maglia, S. polyadenium, S. stoloniferum, S. sparsipilum and S. sucrense, HR to potato A potyvirus (PVA) strain group 1 in S. sucrense and extreme resistance (ER) to PVA in S. polyadenium. S. commersonii and S. stoloniferum expressed HR to tobacco etch potyvirus (TEV) which has not been reported previously in potato species. The studied clone of S. stoloniferum expressed HR to all potyviruses and potyvirus strains tested. The clone of S. stoloniferum (2n=48; nuclear DNAcontent (2C)=3.6 pg) and S. chacoense (2n=24; 2C=1.9 pg) were crossed and 1 hybrid (2n=36; 2C=2.9 pg) was obtained. The hybrid expressed HR to all tested potyviruses except PVA, which indicated that HR to PVA was controlled by a gene which is differentfrom the genes (or gene) controlling HR to PVYO, PVYN, PVV and TEV in S. stoloniferum. On the other hand, S. chacoense and the hybrid expressed ER to cucumber mosaic cucumovirus (CMV), whereas S. stoloniferum was susceptible to CMV. All tested wild species and the 6 tested potato cultivars (S. tuberosum subsp. tuberosum) expressed HR to PVV. Expression of HR following infection with PVYN induced systemic acquired resistance (SAR) in S. chacoense. HR to PVYN in S. sparsipilum and S. sucrense and to PVYOin potato cv. Pito was efficiently expressed at lower temperatures (16/18鳦) indicated by the development of distinct necrotic lesions and/or vein necrosis in inoculated leaves, whereas the HR was rendered less effective at higher temperatures (19/24鳦)which was indicated by the development of systemic infection with leaf-drop and mosaic symptoms.