Le rôle de la ferritine et du fer dans les interactions entre les tubercules de pomme de terre et Streptomyces scabiei
Year: 2022
Type: dissertation
Abstract: Potato (Solanum tuberosum) is an important staple food crop and fourth-most grown in the world. This underground crop has been severely affected by a disease called common scab, which is caused by soil-borne Gram-positive actinobacterium Streptomyces scabiei (syn. S. scabies) leading to deep pitted, raised, superficial or corky lesions on the surface of potato tubers. These lesions reduce the market value of infected tubers resulting in great economic losses. Out of numerous disease control measures practiced so far, the development and use of disease-resistant potato cultivars are being considered as the most effective and less expensive strategy. Studies on the infection process of S. scabiei have shown that it secretes a phytotoxin called thaxtomin A (TA) that is required for the development of disease symptoms, therefore, marking as a pathogenicity determinant for the disease development. Dr. Nathalie Beaudoin’s laboratory developed a new technique to enhance common scab resistance in potato varieties from Quebec by habituating somatic cells to TA. Yukon Gold somaclones YG8 and YG32 produced by this method were significantly more resistant to common scab in comparison to the original cultivar YGP. Quantification analyses for metal content revealed that tubers from scab resistant YG8 and YG32 have 1.5 to 2 times higher iron content compared to YGP. In this project, we found the distribution of iron close to the periderm region of YG8 and YG32, lacking in YGP. In fact, YG8 and YG32 microtubers grown in the presence of S. scabiei accumulated more iron than those of YGP. S. scabiei may compete with microtubers for iron acquisition since siderophore synthesis gene expression was induced in the presence of scab resistant somaclones. Moreover, the previous results from proteomic analysis of YG8 and YG32 revealed the abundance of two ferritin proteins along with other abundant proteins in resistant somaclones as compared to YGP. Ferritins are iron storage proteins that play a role in preventing the high amounts of free iron to react with oxygen and controlling the production of excessive reactive oxygen species by iron sequestration and therefore, maintaining iron homeostasis. Plant ferritins have been found to play a role in plant-pathogen interactions in previous studies. We reported an increase in levels of ferritin (FER1) gene expression in minitubers obtained from these YG somaclones during infection suggesting its involvement in defense mechanisms against S. scabiei. Moreover, the addition of siderophore deferoxamine mesylate (DFOM) seemed to favor bacteria to acquire iron as susceptibility to common scab was restored in the presence of scab resistant YG32 somaclones. The increase in levels of FER1 expression in TA-habituated somaclone Kennebec 39 compared to the original cultivar Kennebec was also reported, suggesting that increased ferritin abundance may potentially contribute to resistance to common scab in other TA-habituated somaclones. Collectively, these results provided a better understanding of the involvement of iron and iron storage protein, ferritin, in possible defense response against pathogen S. scabiei.
Author: Sandhu, Ravinderjit Kaur
Language: English
Subfield: Plant Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: green
OpenAlex ID: W7201360571