Nitrogen fertilization modulates rice phyllosphere functional genes and pathogens through fungal communities.

The phyllosphere is a vital yet often neglected habitat hosting diverse microorganisms with various functions. However, studies regarding how the composition and functions of the phyllosphere microbiome respond to agricultural practices, like nitrogen fertilization, are limited. This study investigated the effects of long-term nitrogen fertilization with different levels (CK, N90, N210, N330) on the functional genes and pathogens of the rice phyllosphere microbiome. Results showed that the relative abundance of many microbial functional genes in the rice phyllosphere was significantly affected by nitrogen fertilization, especially those involved in C fixation and denitrification genes. Different nitrogen fertilization levels have greater effects on fungal communities than bacteria communities in the rice phyllosphere, and network analysis and structural equation models further elucidate that fungal communities not only changed bacterial-fungal inter-kingdom interactions in the phyllosphere but also contributed to the variation of biogeochemical cycle potential. Besides, the moderate nitrogen fertilization level (N210) was associated with an enrichment of beneficial microbes in the phyllosphere, while also resulting in the lowest abundance of pathogenic fungi (1.14 %). In contrast, the highest abundance of pathogenic fungi (1.64 %) was observed in the highest nitrogen fertilization level (N330). This enrichment of pathogen due to high nitrogen level was also regulated by the fungal communities, as revealed through SEM analysis. Together, we demonstrated that the phyllosphere fungal communities were more sensitive to the nitrogen fertilization levels and played a crucial role in influencing phyllosphere functional profiles including element cycling potential and pathogen abundance. This study expands our knowledge regarding the role of phyllosphere fungal communities in modulating the element cycling and plant health in sustainable agriculture.

[Berberine hydrochloride inhibits benign prostatic hyperplasia in rats by activating the Nrf2/ARE pathway].

Objective: To study the inhibitory effect of berberine hydrochloride (BBR) on BPH and its underlying mechanism in male rats. METHODS: Forty male rats were randomly divided into a normal control, a BPH model control, a BBR intervention, and a BBR+Bruceol intervention group, and the BPH model was established in the latter three groups. The animals in the normal and BPH model control groups were treated intragastrically with normal saline, and those in the BBR and BBR+Bruceol intervention groups with BBR at 200 mg/kg and BBR plus Bruceol at 1 mg/kg, respectively, once a day for 14 consecutive days. The prostates of the rats were harvested for measurement of their wet weight and prostatic index, detection of the contents of superoxide dismutase (SOD) and malondialdehyde (MDA) and determination of the protein expressions of nuclear factor E2-related factor 2 (Nrf2), antioxidant response element (ARE) and reduced coenzyme I quinone oxidoreductase (NQO1) in the prostate tissue by Western blot. RESULTS: The wet weights of the prostate in the normal control, BPH model control, BBR intervention, and BBR+Bruceol intervention groups were (715.63 ± 28.57) mg, (1118.93 ± 36.41) mg, (896.21 ± 20.24) mg and (967.23 ± 24.98) mg, the prostate indexes were 2.10 ± 0.13, 3.45 ± 0.22, 2.75 ± 0.19 and 3.01 ± 0.14, the SOD contents in the prostate tissue were (38.54 ± 5.12) U/mg, (13.98 ± 2.01) U/mg, (26.75 ± 3.19) U/mg and (20.16 ± 4.10) U/mg, and the MDA contents were (3.59 ± 0.83) nmol/mg, (12.63 ± 3.26) nmol/mg, (7.20 ± 1.69) nmol/mg and (9.85 ± 1.71) nmol/mg, respectively. The relative expressions of the Nrf2 protein in the four groups were 0.53 ± 0.06, 0.12 ± 0.03, 0.36 ± 0.04 and 0.25 ± 0.03, those of the ARE protein were 0.69 ± 0.07, 0.21 ± 0.02, 0.50 ± 0.06 and 0.30 ± 0.04, and those of the NQO1 protein were 0.44 ± 0.05, 0.15 ± 0.03, 0.30 ± 0.04 and 0.22 ± 0.03, respectively. There were statistically significant differences in all the above indicators between the normal and BPH model control groups (P < 0.05), as well as between the BPH model control and BBR intervention groups (P < 0.05) and between the BPH model control and the BBR+Bruceol intervention groups (P < 0.05). CONCLUSIONS: BBR hydrochloride can inhibit prostatic hyperplasia in BPH rats and reduce oxidative stress and pathological changes by activating the Nrf2/ARE pathway.

Variations of earthworm gut bacterial community composition and metabolic functions in coastal upland soil along a 700-year reclamation chronosequence.

Most ecosystem functions attributed to earthworms are mediated by their internal microbiomes, and these are sensitive to disturbances in the external environment. However, few studies have focused on the response of the earthworm gut microbiome to soil chronosequence. Here, we used 16S rRNA high-throughput sequencing and high-throughput quantitative PCR to investigate the variations in bacterial communities and functional gene abundance in earthworm (Lumbricina sp.) guts and upland soils under 700 years of cultivation. Our results indicated that 700 years of upland cultivation significantly shaped bacterial communities and increased functional traits of microbes in earthworm guts, which were more sensitive to cultivation age compared to the surrounding soils. The earthworm gut bacterial community changed rapidly over the first 300 years of cultivation and then changed slowly in the following centuries. Along with the cultivation age, we also observed that the earthworm gut microbiota was successive towards a copiotrophic strategy (e.g., Xanthobacteraceae, Nocardioidaceae, Hyphomicrobiaceae, and Bacillaceae) and higher potential functions (e.g., ureC, nirS, nosZ, phoD, and pqqC). Furthermore, canonical correspondence analysis further revealed that soil pH, C:N ratio, soil organic carbon, and total nitrogen were key abiotic drivers shaping earthworm gut bacterial communities. Taken together, this study reveals the succession of bacterial communities and potential functions in earthworm guts within 700 years of upland cultivation, which may provide a broader space for us to rationally exploit and utilize the interactions between soil and earthworm gut microbiotas to benefit the soil nutrient cycling process.

Elevation of NO production increases Fe immobilization in the Fe-deficiency roots apoplast by decreasing pectin methylation of cell wall.

Cell wall is the major component of root apoplast which is the main reservoir for iron in roots, while nitric oxide (NO) is involved in regulating the synthesis of cell wall. However, whether such regulation could influence the reutilization of iron stored in root apoplast remains unclear. In this study, we observed that iron deficiency elevated NO level in tomato (Solanum lycopersicum) roots. However, application of S-nitrosoglutathione, a NO donor, significantly enhanced iron retention in root apoplast of iron-deficient plants, accompanied with a decrease of iron level in xylem sap. Consequently, S-nitrosoglutathione treatment increased iron concentration in roots, but decreased it in shoots. The opposite was true for the NO scavenging treatment with 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO). Interestingly, S-nitrosoglutathione treatment increased pectin methylesterase activity and decreased degree of pectin methylation in root cell wall of both iron-deficient and iron-sufficient plants, which led to an increased iron retention in pectin fraction, thus increasing the binding capacity of iron to the extracted cell wall. Altogether, these results suggested that iron-deficiency-induced elevation of NO increases iron immobilization in root apoplast by decreasing pectin methylation in cell wall.

[The relaxation effects of tetrandrine on the corpus cavernosum tissue of rabbit in vitro].

OBJECTIVES: To study the relaxation effects of tetrandrine on the corpus cavernosum tissue of rabbit in vitro. METHODS: 1. The fluctuation of the dose-response relaxation curves for the contraction of KCl induced by tetrandrine was observed with isolated rabbit corpus cavernosum tissue. 2. Isolated strips of rabbit corpus cavernosum tissue were precontracted with 10 mumol/L phenylephrine(PE). Relaxation in response to cumulative doses of tetrandrine was determined in the absence and presence of nitric oxide synthase inhibitor (L-NNA) and soluble guanylate cyclase inhibitor (methylthioninium). RESULTS: 1. The dose-response curves of KCl were shifted to the right nonparallelly, and the maximal responses were depressed to (73.0 +/- 3.8)% and (41.5 +/- 3.4)%, respectively, in the presence of tetrandrine(10 mumol/L, 30 mumol/L). 2. On rabbit cavernosal muscle stripes precontracted with PE(10 mumol/L), increasing concentrations of tetrandrine (1 mumol/L, 10 mumol/L, 30 mumol/L and 100 mumol/L) showed dose dependent relaxation [(6.0 +/- 1.4)%, (21.3 +/- 2.2)%, (47.4 +/- 3.3)%, and (68.1 +/- 3.6)%, P < 0.01]. However, in the meantime, it was found that these relaxation effects were not affected by the presence of L-NNA and methylthioninium (P > 0.05). CONCLUSIONS: Tetrandrine was effective in relaxing rabbit corpus cavernosum tissue in vitro in a dose-dependent style. The mechanism might be related with its blocking effect on calcium channel, but not the NO-cGMP passage.