Find in Library

<i>Castanea sativa</i> is one of the main multipurpose tree species valued for its timber and nuts. This species is susceptible to two major diseases, ink disease and chestnut blight, caused by <i>Phytophthora</i> spp. and <i>Cryphonectria parasitica</i>, respectively. The loss-of-function mutations of genes required for the onset of pathogenesis, referred to as plant susceptibility (S) genes, are one mechanism of plant resistance against pathogens. On the basis of sequence homology, functional domain identification, and phylogenetic analyses, we report for the first time on the identification of S-genes (<i>mlo1</i>, <i>dmr6</i>, <i>dnd1</i>, and <i>pmr4</i>) in the <i>Castanea</i> genus. The expression dynamics of S-genes were assessed in <i>C. sativa</i> and <i>C. crenata</i> plants inoculated with <i>P. cinnamomi</i> and <i>C. parasitica</i>. Our results highlighted the upregulation of <i>pmr4</i> and <i>dmr6</i> in response to pathogen infection. <i>Pmr4</i> was strongly expressed at early infection phases of both pathogens in <i>C. sativa</i>, whereas in <i>C. crenata</i>, no significant upregulation was observed. The infection of <i>P. cinnamomi</i> led to a higher increase in the transcript level of <i>dmr6</i> in <i>C. sativa</i> compared to <i>C. crenata</i>-infected samples. For a better understanding of plant responses, the transcript levels of defense genes <i>gluB</i> and <i>chi3</i> were also analyzed.