Role of the methionine cycle in the temperature‐sensitive responses of potato plants to potato virus Y

Abstract

Potato (Solanum tuberosum) plants, like all other crop plants, are constantly exposed to various pathogenic agents such as bacteria, fungi, oomycetes, nematodes, and viruses. This results in severe crop losses, which ultimately leads to a decline in food production worldwide. Among the various plant pathogens, viruses account for up to 50% of all novel/emerging plant diseases (Whitfield et al., 2015). Potato virus Y (PVY) is one of the most common pathogens of Solanaceae family members, including potato. The most effective and reliable method of plant protection is by increasing plant resistance to viruses. Although plants have evolved multilayered surveillance and defence mechanisms to resist virus infections, it is worth noting

Potato Virus Y Emergence and Evolution from the Andes of South America to Become a Major Destructive Pathogen of Potato and Other Solanaceous Crops Worldwide

“…Remarkably, plant–virus interactions may also be regulated via the interplay between virus accumulation and plant methylation cycles (MTC) [ 63 , 64 ]. The MTC is functionally related to RNAi-based mechanisms, in which siRNAs (as major components of the RNAi-mediated defence response) are stabilized by MTC-associated transmethylation [ 65 ].…”

“…In contrast, RNAi suppression activity of the PVY suppressor HC-Pro is downregulated by higher temperatures, which could decrease defence and enhance PVY infection [ 86 ]. Second, activity of another anti-PVY defence factor, MTC, is significantly perturbed by rising temperatures in potato cv Chicago [ 64 ], resulting in a burst of the PVY infection. Third, SA is involved in both antiviral defence response and the regulation of heat shock protein (HSP) production and heat stress tolerance [ 87 ].…”

The Resistance Responses of Potato Plants to Potato Virus Y Are Associated with an Increased Cellular Methionine Content and an Altered SAM:SAH Methylation Index

“…While there is an orchestrated cross-talk of virus components with host plant machinery during such interactions, there can be an associated dynamic remodelling of host metabolism during the infection process [ 3 ]. A major metabolic process affected by plant virus infections is the methionine cycle (MTC) [ 4 , 5 ].…”

“…Potato virus Y (PVY), the type species of the genus Potyvirus , is one of the most economically important pathogens of potato, and it occurs worldwide [ 15 ]. Interestingly host-PVY interactions, as with many other host-virus interactions, are temperature-sensitive and may be regulated by elevated temperature in a cultivar-specific manner, possibly via the modulation of host defence responses [ 5 , 16 ]. For example, elevated temperatures significantly increase the susceptibility of potato cv.…”

“…Using proteomic transcriptional and metabolomic analyses, we have recently shown that the main enzymes of MTC are down-regulated in PVY-infected Chicago plants at higher temperatures, causing consistent and concerted reduction in the levels of the major MTC metabolites including the methyl group donor SAM. This suggests that the enhanced susceptibility of Chicago potato plants to PVY at high temperatures may at least be partially triggered by the MTC perturbation and concomitant reduction in transmethylation activities [ 5 ].…”