Comparison of resistance to potyviruses within Solanaceae: infection of potatoes with tobacco etch potyvirus and peppers with potato A and Y potyviruses

The reaction of several cultivated potato varieties (Solarium tuberosum L.) to three strains of tobacco etch potyvirus (TEV-F, TEV-Mex21 and TEV-ATCC) and the reaction of several pepper lines (Capsicum annuum L. and C. chinense L.) to two strains of potato Y potyvirus (PVY^O and PVY^N) and one strain of potato A potyvirus (PVA-M) was tested. The potato varieties included in this study carried resistance genes against PVY, PVA and potato V potyvirus, but all were susceptible to TEV and developed mottle and mosaic symptoms. TEV was readily transmitted by mechanical inoculation from tobacco and potato to potato, whereas transmission from pepper to potato occurred infrequently. TEV was transmitted through potato tubers, and from pepper to potato plants by aphids. Lack of detectable systemic infection following graft-inoculation indicated extreme resistance to PVY^O and PVA in several pepper lines. No pepper line was systemically infected with PVY^N following mechanical inoculation (graft-inoculation was not carried out with PVY^N). The development of necrotic lesions following mechanical and graft-inoculation indicated hypersensitive response to PVY^O in several pepper lines which resembled the resistance responses to these potyvirus strains in potato. Results of this study together with previous work indicate that C. annuum cv. Avelar is resistant to four potyviruses PVY, PVA, pepper mottle potyvirus (PepMoV) and some isolates of TEV]; C. annuum cv. Criollo de Morelos and C. chinense PI 152225 and PI 159236 are resistant to three potyviruses (PVY, PepMoV and PVA; and PVY, PepMoV and TEV, respectively); C. annuum 9093–1 and 92016–1 are resistant to PVY and PepMoV; and C. annuum cv. Jupiter and C. annuum cv. RNaky are resistant to PVY^N and PVA.