PRTN3 and infection: Notably, all five <i>Pinus</i> species and one hybrid exhibited upregulation of the <i>elongation factor Tu receptor</i> (<i>EFR</i>) gene and <i>pathogenesis-related (PR)-3</i> gene upon PWN infection, suggesting a potential role of the EF-Tu receptor in detecting PWN invasion and activating the <i>PR-3</i> gene.