Phloem connectivity and transport are not involved in mature plant resistance (MPR) to Potato Virus Y in different potato cultivars, and MPR does not protect tubers from recombinant strains of the virus

Pankaj Kumar; Graham H Cowan; Julie N Squires; Christine A Hackett; Alyson K Tobin; Lesley Torrance; Alison G Roberts

doi:10.1016/j.jplph.2022.153729

Phloem connectivity and transport are not involved in mature plant resistance (MPR) to Potato Virus Y in different potato cultivars, and MPR does not protect tubers from recombinant strains of the virus

J Plant Physiol. 2022 Aug:275:153729. doi: 10.1016/j.jplph.2022.153729. Epub 2022 May 21.

Authors

Pankaj Kumar¹, Graham H Cowan², Julie N Squires³, Christine A Hackett⁴, Alyson K Tobin⁵, Lesley Torrance⁶, Alison G Roberts⁷

Affiliations

¹ Biomedical Sciences Research Complex, School of Biology, North Haugh, University of St Andrews, St Andrews, Fife, KY16 9ST, Scotland, UK. Electronic address: pk20@st-andrews.ac.uk.
² The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, Scotland, UK. Electronic address: graham.cowan@hutton.ac.uk.
³ The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, Scotland, UK. Electronic address: julie.squires@hutton.ac.uk.
⁴ Biomathematics and Statistics Scotland, Invergowrie, Dundee, DD2 5DA, Scotland, UK. Electronic address: christine.hackett@bioss.ac.uk.
⁵ Biomedical Sciences Research Complex, School of Biology, North Haugh, University of St Andrews, St Andrews, Fife, KY16 9ST, Scotland, UK; School of Applied Sciences, Edinburgh Napier University, Edinburgh, EH11 4BN, Scotland, UK. Electronic address: a.tobin@napier.ac.uk.
⁶ Biomedical Sciences Research Complex, School of Biology, North Haugh, University of St Andrews, St Andrews, Fife, KY16 9ST, Scotland, UK; The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, Scotland, UK. Electronic address: lesley.torrance@hutton.ac.uk.
⁷ The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, Scotland, UK. Electronic address: alison.roberts@hutton.ac.uk.

PMID: 35728501
DOI: 10.1016/j.jplph.2022.153729

Abstract

The aims of this study were: i) to investigate mature plant resistance (MPR) against four strains of Potato virus Y (PVY^O, PVY^N, PVY^NTN and PVY^N-Wi) in potato cultivars that differ in maturity (e.g. early or maincrop) at different developmental stages, and ii) to determine whether phloem translocation of photoassimilates at different stages including the source-sink transition influences MPR. The data showed that MPR was functional by the flowering stage in all cultivars, and that the host-pathogen interaction is highly complex, with all three variables (potato cultivar, virus strain and developmental stage of infection) having a significant effect on the outcome. However, virus strain was the most important factor, and MPR was less effective in protecting tubers from recombinant virus strains (PVY^NTN and PVY^N-Wi). Development of MPR was unrelated to foliar phloem connectivity, which was observed at all developmental stages, but a switch from symplastic to apoplastic phloem unloading early in tuber development may be involved in the prevention of tuber infections with PVY^O. Recombinant virus strains were more infectious than parental strains and PVY^NTN has a more effective silencing suppressor than PVY^O, another factor that may contribute to the efficiency of MPR. The resistance conferred by MPR against PVY^O or PVY^N may be associated with or enhanced by the presence of the corresponding strain-specific HR resistance gene in the cultivar.

Keywords: Mature plant resistance; Phloem transport; Potato tuber development; Potato virus Y; Virus movement.

MeSH terms

Host-Pathogen Interactions
Phloem
Plant Diseases
Potyvirus* / genetics
Solanum tuberosum* / genetics