Genetic modification of alternative respiration in Nicotiana benthamiana affects basal and salicylic acid-induced resistance to potato virus X

RNA silencing suppressor genes derived from six virus genera were transformed into Nicotiana benthamiana and N. tabacum plants. These suppressors were P1 of Rice yellow mottle virus (RYMV), P1 of Cocksfoot mottle virus, P19 of Tomato bushy stunt virus, P25 of Potato virus X, HcPro of Potato virus Y (strain N), 2b of Cucumber mosaic virus (strain Kin), and AC2 of African cassava mosaic virus (ACMV). HcPro caused the most severe phenotypes in both Nicotiana spp. AC2 also produced severe effects in N. tabacum but a much milder phenotype in N. benthamiana, although both HcPro and AC2 affected the leaf tissues of the two Nicotiana spp. in similar ways, causing hyperplasia and hypoplasia, respectively. P1-RYMV caused high lethality in the N. benthamiana plants but only mild effects in the N. tabacum plants. Phenotypic alterations produced by the other transgenes were minor in both species. Interestingly, the suppressors had very different effects on crucifer-infecting Tobamovirus (crTMV) infections. AC2 enhanced both spread and brightness of the crTMV-green fluorescent protein (GFP) lesions, whereas 2b and both P1 suppressors enhanced spread but not brightness of these lesions. P19 promoted spread of the infection into new foci within the infiltrated leaf, whereas HcPro and P25 suppressed the spread of crTMV-GFP lesions.

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Soluble, Template-Dependent Extracts from Nicotiana benthamiana Plants Infected with Potato Virus X Transcribe both Plus- and Minus-Strand RNA Templates

Virology ◽

10.1006/viro.2000.0512 ◽

2000 ◽

Vol 275 (2) ◽

pp. 444-451 ◽

Cited By ~ 17

Author(s):

Carol A. Plante ◽

Kook-Hyung Kim ◽

Neeta Pillai-Nair ◽

Toba A.M. Osman ◽

Kenneth W. Buck ◽

...

Keyword(s):

Potato Virus ◽

Nicotiana Benthamiana ◽

Potato Virus X ◽

Minus Strand

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Salicylic Acid Is Involved in the Nb-Mediated Defense Responses to Potato virus X in Solanum tuberosum

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-23-4-0394 ◽

2010 ◽

Vol 23 (4) ◽

pp. 394-405 ◽

Cited By ~ 29

Author(s):

Gerardo Sánchez ◽

Nadia Gerhardt ◽

Florencia Siciliano ◽

Adrián Vojnov ◽

Isabelle Malcuit ◽

...

Keyword(s):

Salicylic Acid ◽

Solanum Tuberosum ◽

Potato Virus ◽

Potato Virus X ◽

Defense Responses ◽

Avirulent Strain ◽

Dependent Manner ◽

Hypersensitive Resistance ◽

Potato Plants ◽

Transgenic Lines

To evaluate the role of salicylic acid (SA) in Nb-mediated hypersensitive resistance to Potato virus X (PVX) avirulent strain ROTH1 in Solanum tuberosum, we have constructed SA-deficient transgenic potato plant lines by overexpressing the bacterial enzyme salicylate hydroxylase (NahG), which degrades SA. Evaluation of these transgenic lines revealed hydrogen peroxide accumulation and spontaneous lesion formation in an age- and light-dependent manner. In concordance, NahG potato plants were more sensitive to treatment with methyl viologen, a reactive oxygen species–generating compound. In addition, when challenged with PVX ROTH1, NahG transgenic lines showed a decreased disease-resistance response to infection and were unable to induce systemic acquired resistance. However, the avirulent viral effector, the PVX 25-kDa protein, does induce expression of the pathogenesis-related gene PR-1a in NahG potato plants. Taken together, our data indicate that SA is involved in local and systemic defense responses mediated by the Nb gene in Solanum tuberosum. This is the first report to show that basal levels of SA correlate with hypersensitive resistance to PVX.

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