RESUMO
Background: In tea plantations with high-pH (pH > 6.5) in Northern China, tea plants are prone to yellowing disease, albinism, and reductions in components that contribute to plant quality, which affect the scale and rate of tea plantation development in Northern China. Methods: To investigate the potential causes of these issues, Camellia sinensis cv. Pingyang Tezao and Camellia sinensis cv. Ruixue were planted in Shouguang city (a high-pH area, soil pH > 6.5) and Rizhao city (a normal-pH area, soil pH is 4.5-5.5), respectively; differences in growth morphology, pigment content, cell structure, quality-determining components, and element content of the two varieties in the two areas were analyzed. Results: The results showed that tea leaves planted in Shouguang had varying degrees of yellowing disease and albinism; the pigment content in both varieties was significantly lower when planted in Shouguang compared with Rizhao. The cell structure was severely damaged and the main quality-determining components were decreased. Nitrogen (N), phosphorus (P), potassium (K), zinc (Zn), copper (Cu) and manganese (Mn) contents in the leaves of the two tea plant varieties were significantly lower when planted in Shouguang compared with those in Rizhao; the levels of these elements in Shouguang soil were significantly higher than in Rizhao soil. Calcium (Ca) contents in Shouguang soil was 9.90 times higher than that of Rizhao soil. Conclusions: We conclude that the soil in high-pH areas hindered tea plant uptake of N, Zn, Cu, and Mn, which had a detrimental effect on chloroplasts and reductions in chlorophyll synthesis, contributing to yellowing disease and albinism. In addition, excessive calcium (Ca) in Shouguang soil was also an important contributor to these negative effects. High-pH soil hindered tea plant uptake of P and K, resulting in reductions in tea polyphenols, amino acids, and other major quality components.
RESUMO
The IL-6-STAT3 axis is critically involved in inflammation-associated carcinogenesis (IAC). How this axis is regulated to modulate IAC remains unknown. Here, we show that the plasma membrane-associated E3 ubiquitin ligase MARCH3 negatively regulates STAT3 activation triggered by IL-6, as well as another IL-6 subfamily member, Oncostatin M (OSM). MARCH3 is associated with the IL-6 receptor α-chain (IL-6Rα) and its coreceptor gp130. Biochemical experiments indicated that MARCH3 mediates the polyubiquitination of IL-6Rα at K401 and gp130 at K849 following IL-6 stimulation, leading to their translocation to and degradation in lysosomes. MARCH3 deficiency increases IL-6- and OSM-triggered activation of STAT3 and induction of downstream effector genes in various cell types. MARCH3 deficiency enhances dextran sulfate sodium (DSS)-induced STAT3 activation, increases the expression of inflammatory cytokines, and exacerbates colitis, as well as azoxymethane (AOM)/DSS-induced colitis-associated cancer in mice. In addition, MARCH3 is downregulated in human colorectal cancer tissues and associated with poor survival across different cancer types. Our findings suggest that MARCH3 is a pivotal negative regulator of IL-6-induced STAT3 activation, inflammation, and inflammation-associated carcinogenesis.
