Molecular identification of Kalanchoe powdery mildew, Erysiphe sedi from Türkiye

Abstract In February 2025, intense powdery mildew disease was observed on leaves and branches of commercial Kalanchoe blossfeldiana grown in Erzurum, Türkiye. The infectious agent was identified both microscopically and molecularly. The results showed that infected K. blossfeldiana plants with Erysiphe sedi . Scanning electron microscopy studies showed that the dimensions of cylinder-shaped conidia were approximately 37.1 × 14.5 μm. As a result of blast nucleotide analysis performed according to Internal transcribed spacer rRNA (ITS) partial region, it was determined that it showed 100% identity with Erysiphe sedi (accession No. MW168996) isolated from Sedum aizoon in China, while it showed 99.83% nucleotide similarity with the previously reported isolate from Türkiye (MT568642). In the phylogenetic analysis performed according to Maximum Likelihood, they clustered together with the Chinese isolate, while they clustered quite far from the other Turkish isolate. In the Kimura-2 parameter analysis performed for advanced molecular analyses, the transition/transversion distance between all E. sedi isolates was determined as 0.000. Sequence demarcation tool (SDTv 1.3) analysis also provided similarity values ​​supporting both the phylogenetic tree results and the Kimura-2 parameter analysis. In this study, detailed morphological and molecular characterization of E. sedi , which was found to infect commercial K. blossfeldiana plants intensively in Türkiye, was performed. This study will shed light on the studies that need to be done to biocontrol powdery mildew caused by E. sedi .