Oaks exhibit unique biological characteristics and high adaptability to complex climatic and soil conditions. They are widely distributed across various regions, spanning 40 degrees latitude and 75 degrees longitude. The total area of oak forest in China is 16.72 million hm². There are 60 lineages of Quercus in China, including 49 species, seven varieties, and four subgenera. Archaeological data indicate that oaks were already widely distributed in ancient times, and they are dominant trees in vast regions of China’s forests. In addition, the acorn was an important food for ancestral humans, and it has accompanied human civilization since the early Paleolithic. Diverse oak species are widely distributed and have great functional value, such as for greening, carbon sequestration, industrial and medicinal uses, and insect rearing. Long-term deforestation, fire, diseases, and pests have led to a continuous decline in oak resources. This study discusses the Quercus species and their distribution in China, ecological adaptation, and the threats facing the propagation and growth of oaks in a changing world. This will give us a better understanding of Quercus resources, and provide guidance on how to protect and better utilize germplasm resources in China. The breeding of new varieties, pest control, and chemical and molecular research also need to be strengthened in future studies.

Chitin deacetylases (CDAs) are carbohydrate esterases associated with chitin metabolism and the conversion of chitin into chitosan. Studies have demonstrated that chitin deacetylation is essential for chitin organization and compactness and therefore influences the mechanical and permeability properties of chitinous structures, such as the peritrophic membrane (PM) and cuticle. In the present study, two genes (ApCDA5a and ApCDA5b) encoding CDA protein isoforms were identified and characterized in Chinese oak silkworm (Antheraea pernyi) larvae. Although five signature motifs were identified, CDA5 proteins only have the chitin-deacetylated catalytic domain. Spatiotemporal expression pattern analyses revealed that both transcripts presented the highest abundance in the anterior region of the midgut during the feeding period after molting, suggesting their role in chitin turnover and PM assembly. The down-regulation of ApCDA5a and ApCDA5b via RNA interference (RNAi) was correlated with the breakage of chitin microfibrils in the PM, suggesting that group V CDAs were essential for the growth and assembly of the chitinous layer. Additionally, ApCDA5a and ApCDA5b may have non-overlapping functions that regulate the morphological characteristics of PM chitin construction in different ways. Larvae injected with double-stranded RNA (dsRNA) against ApCDA5a and ApCDA5b transcripts were less resistant to infection by N. pernyi than those in the control groups. These results revealed that down-regulating ApCDA5a and ApCDA5b had independent effects on the PM structure and undermined the intactness of the PM, which disrupted the function of the PM against microsporidia infection per os. Our data provide new evidence for differentiating CDA functions among group V CDAs in lepidopteran insects.

Drought is a significant environmental limiting factor that restricts the growth of Quercus wutaishanica Mayr. The MYB transcription factor plays a wide role in controlling the growth of plants. In this study, the QwMYB108 gene was cloned and the bioinformatics was analyzed, and we examined how QwMYB108 responded to various gradient drought stresses. The results demonstrated that QwMYB108 encoded 275 amino acids using an 828 bp open reading frame. Subcellular localization indicated that the gene was located in the nucleus. Phylogenetic analysis showed that QwMYB108 was close to Q. robur, and that the highest level of expression was found in leaves, which was significantly different from other tissues. The expression of QwMYB108 increased as the stress degree rose when drought stress was present, and there was a significant difference between severe drought stress and other gradient stress. In this study, the function of QwMYB108 in drought stress response was investigated, and the drought response function gene of Q. wutaishanica was further explored to provide a theoretical basis.