Peach (Prunus persica L.) gummosis, mainly caused by Botryosphaeria dothidea, is common in the United States and China (Reilly and Okie 1982; Wang et al. 2011). It causes significant growth stunting, can even result in tree death, overwhelmingly affecting peach cultivation and production. Gum exudation from peach tree trunks was observed in orchards located at Huazhong Agricultural University (Wuhan, China) in 2011. The incidence of gummosis was 100% in 2013 and the symptoms were more severe from May to September. To identify the causal agent of the disease, spore trapping in 2013 and isolation of fungi from different diseased tissues of peach cultivar (cv.) Spring Snow based on the study of Wang et al (2011) in 2015 were done. Scotch tapes with adhered spores and treated tissue samples were cut into 5 mm wide pieces and placed on potato dextrose agar (PDA) plates then incubated at 28°C for 3 days, respectively. Visual hyphae were transferred to fresh PDA plates by the hyphal-tip method to obtain pure cul...

Actinidia latifolia, with the highest vitamin C content in its genus, is a unique wild relative of kiwifruit that could be important for genetic breeding research. Climate change significantly influences the distribution range of wild plants. Accurately assessing the potential distribution of wild kiwifruit and its response to climate change is crucial for the effective protection and sustainable utilization of its germplasm resources. In this study, we utilized the optimized MaxEnt model to predict the potential habitats of A. latifolia in China, employing the jackknife test to assess the importance of environmental variables in our modeling process. The results showed that annual precipitation (Bio12) and temperature annual range (Bio7) emerged as the most influential environmental variables affecting the distribution of this kiwifruit wild relative. As radiative forcing and time increase, the potential habitats of A. latifolia in China are projected to shrink southward, thereby exacerbating habitat fragmentation. This research offers significant scientific references for the investigation, protection, cultivation, and application of wild relatives of the kiwifruit.

The kiwifruit canker disease caused by Pseudomonas syringae pv. actinidiae (Psa) seriously threatens the development of kiwifruit industry. So far, only a limited number of Psa-resistant kiwifruit varieties have been identified, and the underlying molecular mechanisms are still largely unknown. In this study, we evaluated the Psa resistance of six hybrid populations and screened a resistant segregation population R₁F₂. Then, transcriptome analysis on the Psa extremely high-resistant (HR) and extremely high-susceptible (HS) plants of the R₁F₂ population was performed. KEGG enrichment analysis revealed that differentially expressed genes (DEGs) were significantly enriched in plant hormone signal transduction pathways, including auxin, abscisic acid, zeatin, jasmonic acid and salicylic acid. Furthermore, several transcription factors (TFs), especially WRKY TFs, were identified among the DEGs. The qRT-PCR showed that AcWRKY75 was highly expressed in the HS plants. Additionally, AcWRKY75 was significantly induced in the HS cultivar ‘Hongyang’ after Psa inoculation. Sequence amplification analysis showed that there was polymorphism in the DNA sequence of AcWRKY75 gene, but no HR or HS-specific differences were observed. Subcellular localization and transcriptional activity analysis confirmed that AcWRKY75 functions as a nucleus-located transcriptional activator. Transient overexpression of AcWRKY75 in kiwifruit leaves reduced the resistance to Psa, while silencing AcWRKY75 by virus-induced gene silencing (VIGS) slightly enhanced the resistance to Psa. Furthermore, AcWRKY75 exhibited a weak interaction with the promoter of the ABA-related DEG AcBet V1 (Acc27163). Our findings elucidated that AcWRKY75 may negatively regulate the Psa resistance of kiwifruit through the hormone signaling pathway, which laid a foundation for the analysis of the disease resistance mechanism of kiwifruit canker.