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Expression patterns of plant defense genes during early stem infection of susceptible and tolerant potatoes by Dickeya dadantii

Yingyu Liu: Cornell University

<div><em>Dickeya</em> spp. are necrotrophic bacterial pathogens that cause blackleg disease in potatoes. Blackleg disease has resulted in significant economic losses in the United States since 2015 and continues to devastate the potato industry. Breeding for resistance to blackleg in potato cultivars is difficult due to the limited understanding of genetic mechanisms of host-microbe interactions in this pathosystem. To better understand the plant defense response to <em>Dickeya</em>, quantitative reverse transcription polymerase chain reactions (qRT PCR) were performed with cDNA libraries made from total RNA. These RNAs were extracted from susceptible or tolerant diploid potato stems inoculated with<em> D. dadantii</em> 3937 or mock buffer at 0 and 12-hours post inoculation. qRT-PCR experiments between mock and <em>D. dadantii</em> inoculated potatoes revealed changes in expression patterns of genes related to plant defense activation, including pathogen-associated molecular pattern-triggered immunity hallmark genes (<em>Pti5</em>, <em>Gras2</em>, <em>Lrr22</em>), the flagellin receptor gene (<em>FLS2</em>), a salicylic acid regulated gene (<em>PR1</em>), and a jasmonic acid dependent gene (<em>TPI-1</em>). Differential expression of these genes could contribute to the tolerance or susceptibility of the two potato lines to <em>Dickeya</em> spp. Our study of targeted potato defense genes expression patterns provides novel information regarding plant defense mechanisms in the <em>Dickeya</em>-potato pathosystem at an early infection stage.</div>