Based on the importance and sensitivity of microbial communities to changes in the forest ecosystem, soil microorganisms can be used to indicate the health of the forest system. The metagenome sequencing was used to analyze the changes of microbial communities between natural and plantation Castanea henryi forests for understanding the effect of forest types on soil microbial communities. Our result showed the soil microbial diversity and richness were higher in the natural forests than in the plantation. Proteobacteria, Actinobacteria, and Acidobacteria are the dominant categories in the C. henryi rhizosphere, and Proteobacteria and Actinobacteria were significantly enriched in the natural forest while Acidobacteria was significantly enriched in the plantation. Meanwhile, the functional gene diversity and the abundance of functions in the natural forest were higher than that of the plantation. Furthermore, we found that the microbial network in the natural forests had more complex than in the plantation. We also emphasized the low-abundance taxa may play an important role in the network structure. These results clearly showed that microbial communities, in response to different forest types, provide valuable information to manipulate microbiomes to improve soil conditions of plantation.

Advancement of the oil tea industry requires the development of high-yielding and superior-quality varieties of Camellia oleifera, a major oilseed crop. However, traditional breeding methods, hampered by lengthy cycles and low selection accuracy, significantly constrain the breeding process. Identifying single nucleotide polymorphisms (SNPs) associated with target traits, and applying molecular marker-assisted selection (MAS) for these traits, can thereby shorten the breeding cycles and amplify the breeding efficiency. In this study, we utilized the hexaploid C. oleifera as the reference genome to identify high-quality SNPs and constructed a high-density genetic linkage map of C. oleifera that spanned 1566.733 cM, included 3097 SNPs, and was anchored to 15 linkage groups. Using interval mapping, we localized quantitative trait loci (QTLs) for 11 juvenile traits in C. oleifera, identifying 15 QTLs for growth traits and 24 QTLs for leaf traits, including 4 stable QTLs. The logarithm of odds (LOD) scores for individual QTLs ranged from 3.48 to 14.62, explaining 9.86–48.61% of the phenotypic variance. We further identified 2 SNPs associated with growth traits (marker11-951 and marker12-68) and 10 SNPs associated with leaf traits (marker11-276, marker11-410, marker11-560, marker13-16, marker13-39, marker13-110, marker13-731, marker14-701, marker14-910, and marker14-1331). These results provide valuable insights into the genetic mapping of key traits in C. oleifera and will contribute to the development of new varieties with high yield and superior quality in the future.

Tea oil is an important high-quality edible oil derived from woody plants. Camellia oleifera is the largest and most widely planted oil-producing plant in the Camellia genus in China, and its seeds are the most important source for obtaining tea oil. In current research, improving the yield and quality of tea oil is the main goal of oil tea genetic breeding. The aim of this study was to investigate the degree of genetic variation in an early crossing population of C. oleifera and identify single nucleotide polymorphisms (SNPs) and genes significantly associated with fruit traits, which can provide a basis for marker-assisted selection and gene editing for achieving trait improvement in the future. In this study, we selected a crossing population of approximately 40-year-old C. oleifera with a total of 330 samples. Then, ddRAD sequencing was used for SNP calling and population genetic analysis, and association analysis was performed on fruit traits measured repeatedly for two consecutive years. The research results indicate that over 8 million high-quality SNPs have been identified, but the vast majority of SNPs occur in intergenic regions. The nucleotide polymorphism of this population is at a low level, and Tajima’s D values are mostly greater than 0, indicating that the change in this population was not suitable for the model of central evolution. The population structure analysis shows that the population has seven theoretical sources of genetic material and can be divided into seven groups, and the clustering analysis results support the population structure analysis results. Association analysis identified significant SNPs associated with genes related to the seed number of a single fruit and seed kernel oil content. Our findings provide a basis for molecular breeding and future genetic improvement of cultivated oil tea.