Endogenous bacteria inhabiting the Ophiocordyceps highlandensis during fruiting body development

Background The genus Ophiocordyceps, which includes Ophiocordyceps sinensis, has been demonstrated to be one of the most valuable medicinal taxa. The low rate of larval infection and slow development that characterize the cultivation of this genus should be urgently addressed. To identify potential bioinoculants that stimulate the growth of Ophiocordyceps, O. highlandensis was selected as a model system, and a total of 72 samples were collected to systematically compare the microbial communities present during fruiting body development. By applying high-throughput 16S and ITS2 amplicon sequencing technology, the bacterial and fungal communities were identified in O. highlandensis and its surrounding soil, and the functional dynamics of the bacteria were explored. Results The results indicate that the most abundant bacteria across all the samples from O. highlandensis were Proteobacteria, Firmicutes and Bacteroidetes, while members of Ascomycota were detected among the fungi. The pathways enriched in the developmental stages were associated with carbohydrate degradation, nucleotides and pyridoxal biosynthesis, and the TCA cycle. Compared with that in the fungal community, an unexpectedly high taxonomic and functional fluctuation was discovered in the bacterial community during the maturation of O. highlandensis. Furthermore, bipartite network analysis identified four potential supercore OTUs associated with O. highlandensis growth. Conclusions All the findings of this study suggest unexpectedly high taxonomic and functional fluctuations in the bacterial community of O. highlandensis during its maturation. O. highlandensis may recruit different endogenous bacteria across its life cycle to enhance growth and support rapid infection. These results may facilitate Ophiocordyceps cultivation and improve the development of strategies for the identification of potential bioinoculant resources.

Influence of nitrogen and mineral fertilizer application rates for legumes on the number of stems and the amount of NPK in the soil

Inoculation of seeds of legumes (soybean - Glycine max L., mung bean - Phaseolus aureus L., wild beans - Phaseolus) grown as a secondary crop after winter wheat before sowing with nitragin and application of mineral fertilizers in different doses affected the amount of endogenous bacteria formed in the plant root as well as the agrochemical properties of the soil. Inoculation of legume seeds with nitragin before sowing and application of mineral fertilizers at different rates increased the amount of humus in the topsoil (0-30 cm) layer by 0.025-0.029% compared to the initial values, and the total nitrogen content by 0.009-0.012%. The formation of endogenous bacteria in the root of the plant was inoculated with nitrogen before sowing the seeds of soybean, moss, bean crops. The amount of legumes was 22.7-36.7 pieces in the variant, in which the mineral fertilizers N30 R90 K60 kg/ha was applied, whereas it was 12.0-15.6 pieces in the variant without any mineral fertilizers.

Isolation of Endophytic Bacteria and Amplification of 16SrDNA on Citrus in Zhaoqing Districts

<p>Zhaoqing is the main source of Citrus in China. However, the reason of citrus Huanglongbing (HLB) is unclear and may be from endophyte. Therefore, the study of citrus endophyte is necessary. The experiment would be carried out by endophyte being isolated from citrus plant and amplifying the specific 16SrDNA fragment from endogenous bacteria to know the relation of citrus HLB to 16S rDNA of endogenous bacteria. The results showed that total 55 strains of endophytic bacteria were identified. And one specific fragment long of 1261 nt was got. Sequencing analysis showed for 91.3% homology to uncultured bacterium clone. And the 16SrDNA fragment was identified by PCR. The experiments would provide a theoretical basis for understanding the differences in pathomechanism among various HLB isolates.</p>