The impacts of rice varieties with stacked drought tolerance and insect resistance on soil microbiomes are poorly understood. Hence, the objective of this study was to investigate the effects resulting from the cultivation of the drought-tolerant and insect-resistant rice cultivar, Hanhui3T, on soil physical–chemical properties, and bacterial and fungal community composition. Soil samples of Hanhui3T and conventional rice varieties (Hanhui3 and Zhonghua11) were collected in triplicate at the booting stage, and bacterial and fungal population sizes and community structures were assessed using qPCR and Illumina MiSeq sequencing, respectively. The Bt protein concentration of Hanhui3T was significantly higher than that of Hanhui3 and Zhonghua11, while the pH of Hanhui3T was significantly lower. Bacterial population sizes and community composition were significantly different between Hanhui3T and Hanhui3 (or Zhonghua11), while no similar effects were observed for fungal communities. These differences suggest that the effect of Hanhui3T cultivation on bacterial community composition is stronger than the effect on fungal communities. Moreover, bacterial abundance was positively correlated to soil pH, while bacterial community structure variations were mainly driven by soil pH and Bt protein concentration differences. In conclusion, the abundances and structure of bacterial communities were altered in rhizosphere with Hanhui3T cultivation that changed soil pH and Bt protein concentrations, while fungal communities displayed no such responsiveness.

The demand for molecular analysis of aquatic microbial communities in freshwater has highlighted the need for efficient methods of DNA extraction. The centrifugation method and filtration-membrane method are 2 widely used methods for extracting DNA. The objective of this study was to compare the extraction efficiency of 3 methods, including the centrifugation method, filtration-membrane method, and modified filtration-membrane method, by evaluating the quantity and purity of DNA extracts obtained from water. DNA extraction was analyzed by agarose gel electrophoresis, ultraviolet-spectroscopy, restriction enzyme digestion, and polymerase chain reaction. The results showed that the modified filtration-membrane method was the most efficient for extracting microbial DNA from freshwater with high integrity and purity and is suitable for molecular applications.

The phyllosphere represents the largest biological surface on Earth and serves as an untapped reservoir of functional microbiota. The phyllosphere microbiome has the potential to mitigate plant diseases; however, limited information exists regarding its role in maintaining plant health. In this study, metagenomic sequencing was employed to analyze the microbiomes of the adaxial and abaxial leaf surfaces of healthy (CKWT) and diseased (EWT) maize, with the aim of dissecting the influence of Exserohilum turcicum on phyllosphere microbiome function. E. turcicum altered the alpha and beta diversity of the phyllosphere microbiome, with the Shannon diversity and Chao1 index values significantly reduced in EWT. More beneficial microbes accumulated in the CKWT phyllosphere, whereas pathogenic microbes decreased. E. turcicum may have altered the balance between commensal and pathogenic microorganisms. The species and abundances of microorganisms on the two sets of leaf surfaces were also altered after inoculation with E. turcicum. Further analysis of disease-resistance-related metabolic pathways and abundances of antibiotic-resistance genes revealed that E. turcicum altered the abundance of the functional microbiome and modified the microbiome differences between adaxial and abaxial leaf surfaces. In conclusion, the results reveal that microbial diversity in the maize phyllosphere can influence the microbiome and regulate microbial functions to support plant health. These findings enhance our understanding of how E. turcicum affects the phyllosphere microbiome and provide a theoretical basis for biological control of E. turcicum.

The phyllosphere is one of the largest habitats for microorganisms, and host genetic factors play an important role during the interaction between microorganisms and the phyllosphere. Therefore, the transgene may also lead to changes in the maize phyllosphere. ZmMYB3R was identified as a drought-tolerant gene in Arabisopsis. Here, we employed metagenomic sequencing to analyze the microbiome of the adaxial and abaxial leaf surfaces on ZmMYB3R-overexpressing (OE) and wild-type (WT)·maize, aiming to dissect the possible associations between ZmMYB3R and changes in phyllosphere microbiome functioning. Our results revealed that overexpressing ZmMYB3R altered the alpha and beta diversity of the phyllosphere microbiome. In OE plants, more beneficial microbes accumulated on the phyllosphere, while pathogenic ones diminished, especially on the abaxial surface of ZmMYB3R leaves. Further analysis of disease resistance-related metabolic pathways and abundances of disease resistance genes revealed significant differences between OE and WT. The inoculation experiment between OE and WT proved that ZmMYB3R increased the disease resistance of maize. In conclusion, the results reveal that transgenes affect the phyllosphere microbiome, and ZmMYB3R might alter leaf disease resistance by reshaping the phyllosphere microbiome structure. These findings help us understand how ZmMYB3R regulates leaf disease resistance and may facilitate the development of disease control by harnessing beneficial microbial communities.