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Elucidating the Key Roles of Arabidopsis ETHYLENE RESPONSE 1 and ETHYLENE INSENSITIVE 3 in Mediating Plant Susceptibility to Beet Cyst Nematode

Sarbottam Piya: University of Tennessee

<div>Ethylene regulates various physiological and developmental processes including plant defense responses. In response to pathogen attack, plants frequently activate the ethylene biosynthesis pathway, leading to the induction of ethylene-dependent defense signaling. The role of ethylene in establishing the compatible interaction between host plants and cyst nematodes has become more apparent. Previous studies have identified ETHYLENE RESPONSE 1 (ETR1) and ETHYLENE INSENSITIVE 3 (EIN3) as positive regulators of Arabidopsis susceptibility to the beet cyst nematode <em>Heterodera schachtii. </em>However, the mechanisms through which ethylene perception and signaling regulate Arabidopsis response to cyst nematode infection remain largely elusive. The aim of this study was to elucidate the role of various components of ethylene perception and signaling in the Arabidopsis-<em>H. schachtii</em> interaction. Our results point to a vital role of the ETR1 receiver domain in ETR1-mediated Arabidopsis susceptibility to <em>H. schachtii</em>. We identified specific amino acid residues in the ETR1 receiver domain that contribute to the sub-functionalization of the ETR1 to regulate Arabidopsis susceptibility to <em>H. schachtii</em>. Pharmacological assays also revealed a role of cytokinin in ETR1-mediated Arabidopsis susceptibility to <em>H. schachtii</em>. Our results also pointed into a potent crosstalk between ethylene and salicylic acid signaling during the interaction. Collectively, our results contribute to a better understating of the function of ethylene and its interplay with other stress-related hormones during nematode parasitism of Arabidopsis.</div>