Assessment of Resistance to PVY in Interspecific Hybrids Obtained by Combining Type <i>va</i> Resistance from <i>Nicotiana tabacum</i> with the Resistance from PVY-Immune Species <i>Nicotiana africana</i>
Tobacco veinal necrosis caused by the potato virus Y (PVY) substantially affects yields and crop quality of tobacco. PVY shows high variability in virulence due to numerous mutations and recombinations. The types of resistance available for tobacco include the <i>va</i> type, effective a...
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| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-12-01
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| Series: | Agriculture |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2077-0472/14/12/2284 |
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| Summary: | Tobacco veinal necrosis caused by the potato virus Y (PVY) substantially affects yields and crop quality of tobacco. PVY shows high variability in virulence due to numerous mutations and recombinations. The types of resistance available for tobacco include the <i>va</i> type, effective against some PVY isolates but succumbing to others, and the <i>Nicotiana africana</i>-derived type, fully effective in its native genetic milieu but limited to varying degrees of tolerance when transferred to <i>N. tabacum</i>. The objective of this study was to evaluate the pyramiding potential of these two sources of resistance in alloploid hybrids of <i>Nicotiana tabacum</i> x <i>N. africana</i>. To this end, amphidiploids involving <i>N. tabacum</i> cvs. VAM and Wiślica, each being the carrier of a different variant of the <i>va</i> gene, were created and advanced from F<sub>1</sub> to two subsequent selfed generations and to BC<sub>1</sub> generation with either VAM or Wiślica as the recurrent <i>N. tabacum</i> parent. The hybrid populations thus produced were challenged with two PVY necrotic isolates, IUNG 23 and IUNG 20, mild and severe isolate belonging to the PVY<sup>N-Wi</sup> and PVY<sup>NTN</sup> groups, respectively. The mild isolate failed to infect any of the hybrids or parental species. The hybrids varied in their response to IUNG 20. The F<sub>1</sub> and F<sub>2</sub> populations were composed of asymptomatic hosts to PVY and of those showing mild vein clearing but no necrotic plants. There was a progressive increase in ability to resist PVY in successive amphidiploid generations, with 30 and 10% of fully resistant plants appearing in the F<sub>3</sub> amphidiploids involving VAM and Wiślica. Further research is needed to account for the appearance of segregants completely resistant to PVY, since neither <i>N. africana</i> factor is fully expressed in <i>N. tabacum</i>, nor do the <i>va</i> alleles confer resistance against PVY<sup>NTN</sup> isolates. |
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| ISSN: | 2077-0472 |