School of Ecology and Environmental System, Kyungpook National University, Sangju, 37224, Republic of Korea; Tree Diagnostic Center, Kyungpook National University, Sangju, 37224, Republic of Korea.
Micron. 2021 Apr;143:103013. doi: 10.1016/j.micron.2021.103013. Epub 2021 Jan 22.
The morphology and surface characteristics of the powdery mildew Erysiphe australiana growing on crape myrtle leaves were observed with field emission scanning electron microscopy. The powdery mildew infection caused distortion and withering of the leaves, and nearly all external parts such as flowers, petioles, and branches were covered by the whitish colonies. Hyphal proliferation was prevalent on the adaxial surface of the powdery mildew-infected leaves. Globose ascocarp initials with hyphal aggregations were frequently seen on the leaf surface. Collapsed conidia showed longitudinal striations or ridges on the surface and deep linear wrinkling. Foot-cells were straight and grew at right angles from the vegetative hyphae. The conidiophores had fragmented, cylindrical, non-chained conidia which were produced singly at the apex of the conidiophores. The germ tubes formed intercalary multi-lobed appressoria and the conidia produced filiform protrusions emerging from subterminal positions. This study visualized previously unknown structures of E. australiana such as the ascocarp initials, filiform protrusions on conidia, and multi-lobed appressoria on germ tubes. These observations will facilitate the identification and taxonomy of this fungus and its allied species.
采用场发射扫描电子显微镜观察了紫薇白粉病菌（Erysiphe australiana）在紫薇叶片上的形态和表面特征。白粉病感染导致叶片扭曲和枯萎，几乎所有外部部分，如花、叶柄和枝条，都被白色的菌落覆盖。菌丝在白粉病感染叶片的上表面广泛增殖。在叶片表面经常可以看到带有菌丝聚集的球形子囊果初始物。塌陷的分生孢子在表面具有纵向条纹或脊线，并有深的线性皱折。足细胞笔直，从营养菌丝垂直生长。分生孢子梗具有破碎的、圆柱形的、不链生的分生孢子，它们单独地在分生孢子梗的顶端产生。芽管形成中间多裂片的附着胞，并且从末端位置产生丝状突起。本研究直观地展示了 E. australiana 的以前未知的结构，如子囊果初始物、分生孢子上的丝状突起和芽管上的多裂片附着胞。这些观察结果将有助于该真菌及其相关种的鉴定和分类。
