Mulberry fruit sclerotiniosis is a common soil-borne disease. We hypothesize that there is a relationship between the incidence of mulberry fruit sclerotiniosis and the soil fungal community. Therefore four mulberry genotypes with different resistance to sclerotiniosis were selected to study their soil fungal community under the same condition. A total of 6 phyla and 93 genera were identified from all mulberry samples. Genera affected by genotype, cover, and genotype by cover interactions, were 23, 20, and 11, respectively. There were 10 genera that differed between the resistant cultivars and the susceptible cultivars. In addition, the relative abundances of Humicola and Mortierella in the resistant mulberry cultivars with the cover treatments were significantly higher than that of in the susceptible cultivars. However, the relative abundance of Sclerotiniaceae and Scleromitrula that may cause sclerotiniosis in the uncover treatments were significantly higher compared with the cover treatments. The results suggested that the genotype of mulberry has a significant impact on the soil microbial community that may result in differences in resistance to sclerotiniosis, and covering could reduce the relative abundance of Sclerotiniaceae or Scleromitrula.

The conversion of intrinsic lands to anthropogenic uses has increased nutrient inputs for lake microbes, profoundly influencing biogeochemical processes, particularly carbon cycling. Microbial carbon utilization is crucial in lake carbon sequestration, but its general changes under anthropogenic disturbances remain controversial. We combined carbon utilization assays with Biolog EcoPlates and 16S rRNA gene amplicon sequencing to examine microbial carbon utilization and carbon loss in lakes along a 3369 km gradient of land-use intensities spanning the Yangtze River and its front basin across China. Our results demonstrated that >30% land-use conversions from intrinsic to anthropogenic lands (farmland and built areas) resulted in >50% carbon loss in lakes. The large carbon loss was primarily driven by elevated nutrient concentrations, which stimulated microbial carbon utilization. Microbes in water were more responsive to environmental changes than those in sediment. We further identified distinct preferences of microbial carbon utilization driven by compositional shifts in core species. Specifically, nutrient-sensitive species (Roseomonas and Methylocystis) were replaced by nutrient-preferential species (Desertimonas and Clostridium sensu stricto), which collectively enhanced the utilization of substrates such as itaconic acid, phenylethyl-amine and glycerol, thereby accelerating carbon loss. This study quantifies the relationship between microbial carbon utilization and carbon loss, emphasizing the importance of regulating land-use changes and nutrient inputs to mitigate their impacts on lakes.

Mulberry fruits are rich in anthocyanins, which are important secondary metabolites that give mulberries their bright color, favorable taste and high nutritional quality, making them a popular fruit. However, few studies have focused on the molecular mechanism underlying anthocyanin accumulation in mulberries and the gene regulatory networks of anthocyanin biosynthetic pathways remain largely unknown. In this study, we performed RNA sequencing to identify differentially expressed genes (DEGs) associated with anthocyanin accumulation between two mulberry genotypes (‘Zi Jing’, ZJ and ‘Zhen Zhu Bai’, ZZB, with purple and white fruit flesh, respectively) at 5, 18, 27 and 31 days after flower. Using transcriptome analysis, we explored several key DEGs involved in the anthocyanin biosynthetic pathway, including the structural genes: CHS, CHI, F3H, DFR1, DFR2 and ANS, known as MBW complex genes: MYB (M.alba_G0017209), MYB (M.alba_G0017689), bHLH (M.alba_G0012659), bHLH (M.alba_G0009347) and bHLH3 (M.alba_G0016257) and the ethylene response factor: ERF (M.alba_G0016603). Of these, changing trends related to expression pattern and anthocyanin content showed their most positive correlation at the post-flowering stage in both genotypes. Our results indicated that ethylene enhances anthocyanin accumulation in mulberry fruits. Furthermore, qRT-PCR was performed to confirm the above-mentioned genes’ expression (except for MYB (M.alba_G0017689) and bHLH (M.alba_G0009347) was significantly up-regulated under ethylene treatment at 300 mg/L. These findings help uncover the gene regulatory networks of the anthocyanin biosynthetic pathway and will contribute to engineering purposes in future mulberry breeding programs.