Identification of Fungal Species Associated with Apple Canker in Tarim Basin, China.

Apple canker has decreased yields of the economically important apple (Malus domestica) crop in China in recent years. Pathogen identity is highly challenging and the disease is poorly understood. Specimens of 339 fungi were isolated from apple trees in the primary apple-producing region in the Tarim Basin during the current study. In total, nine species of Cytospora and five species of the family Botryosphaeriaceae were identified by morphological observation and multilocus phylogenetic analyses: internal transcribed spacer (ITS), actin, translation elongation factor (TEF), and ß-tubulin (TUB) gene regions for Cytospora and ITS, TEF, and TUB for Botryosphaeriaceae. Cytospora pyri from the Cytospora genus was the dominant species causing apple canker in the Tarim Basin. C. melnikii, C. tritici, C. euonymina, Diplodia seriata, and Botryosphaeria dothidea have been described as the cause of apple canker in China. Apple (Red Fuji) branches were utilized to assess the pathogenicity of 24 representative fungal isolates from the 14 species, and branches from seven distinct woody plants (Korla pear, walnut, Chinese date, Xinjiang poplar, sand jujube, Populus euphratica, and willow) were utilized to analyze the host range. The main pathogenic fungal species of apple canker around the Tarim Basin were identified and biological characteristics explored. Pathogen diversity and regional source diversity were assessed with host range and pathogenicity. The aim was to provide a theoretical foundation for the prevention and treatment of apple canker.

Drebrin and Spermatogenesis.

Drebrin is a family of actin-binding proteins with two known members called drebrin A and E. Apart from the ability to stabilize F-actin microfilaments via their actin-binding domains near the N-terminus, drebrin also regulates multiple cellular functions due to its unique ability to recruit multiple binding partners to a specific cellular domain, such as the seminiferous epithelium during the epithelial cycle of spermatogenesis. Recent studies have illustrated the role of drebrin E in the testis during spermatogenesis in particular via its ability to recruit branched actin polymerization protein known as actin-related protein 3 (Arp3), illustrating its involvement in modifying the organization of actin microfilaments at the ectoplasmic specialization (ES) which includes the testis-specific anchoring junction at the Sertoli-spermatid (apical ES) interface and at the Sertoli cell-cell (basal ES) interface. These data are carefully evaluated in light of other recent findings herein regarding the role of drebrin in actin filament organization at the ES. We also provide the hypothetical model regarding its involvement in germ cell transport during the epithelial cycle in the seminiferous epithelium to support spermatogenesis.