Combined application of chemical fertilizers with organic amendments was recommended as a strategy for improving yield, soil carbon storage, and nutrient use efficiency. However, how the long-term substitution of chemical fertilizer with organic manure affects rice yield, carbon sequestration rate (CSR), and nitrogen use efficiency (NUE) while ensuring environmental safety remains unclear. This study assessed the long-term effect of substituting chemical fertilizer with organic manure on rice yield, CSR, and NUE. It also determined the optimum substitution ratio in the acidic soil of southern China. The treatments were: (i) NPK0, unfertilized control; (ii) NPK1, 100% chemical nitrogen, phosphorus, and potassium fertilizer; (iii) NPKM1, 70% chemical NPK fertilizer and 30% organic manure; (iv) NPKM2, 50% chemical NPK fertilizer and 50% organic manure; and (v) NPKM3, 30% chemical NPK fertilizer and 70% organic manure. Milk vetch and pig manure were sources of manure for early and late rice seasons, respectively. The result showed that SOC content was higher in NPKM1, NPKM2, and NPKM3 treatments than in NPK0 and NPK1 treatments. The carbon sequestration rate increased by 140, 160, and 280% under NPKM1, NPKM2, and NPKM3 treatments, respectively, compared to NPK1 treatment. Grain yield was 86.1, 93.1, 93.6, and 96.5% higher under NPK1, NPKM1, NPKM2, and NPKM3 treatments, respectively, compared to NPK0 treatment. The NUE in NPKM1, NPKM2, and NPKM3 treatments was higher as compared to NPK1 treatment for both rice seasons. Redundancy analysis revealed close positive relationships of CSR with C input, total N, soil C:N ratio, catalase, and humic acids, whereas NUE was closely related to grain yield, grain N content, and phenol oxidase. Furthermore, CSR and NUE negatively correlated with humin acid and soil C:P and N:P ratios. The technique for order of preference by similarity to ideal solution (TOPSIS) showed that NPKM3 treatment was the optimum strategy for improving CSR and NUE. Therefore, substituting 70% of chemical fertilizer with organic manure could be the best management option for increasing CSR and NUE in the paddy fields of southern China
Carotenoids are involved in the formation of plant leaf color as well as photosystem photoprotection. This study showed that blue light significantly induced up-regulation of the total carotenoid content in the inner leaves of orange-head Chinese cabbage (OHCC). Furthermore, the transcriptomic analysis revealed that blue light treatment induced up-regulation of genes in photosynthesis (BrHY5-2, BrCOP1 and BrDET1) and the methylerythritol 4-phosphate pathways (BrGGPS, BrDXS and BrHDR) upstream of the carotenoid metabolic pathway. Carotenoid metabolomic analysis revealed that the accumulation of several orange and red carotenoids (lycopene, zeaxanthin, β-carotene, lutein, and β-cryptoxanthin) after blue light treatment contributed to the deepening of the leaf coloration, suggesting that short-term blue light treatment could be used to boost nutritional quality. The light signal gene BrHY5-2 participated in the blue light-induced transcriptional regulation of carotenoid biosynthesis in OHCC. Overexpression of BrHY5-2 in Arabidopsis significantly increased the total carotenoid content and the sensitivity to blue light. The above findings revealed new insights about blue-light-induced carotenoid synthesis and accumulation in OHCC lines. They suggested a new engineering approach to increase the nutritional value of vegetables.
In yeast, the stress-responsive protein Whi2 interacts with phosphatase Psr1 to form a complex that regulates cell growth, reproduction, infection, and the stress response. However, the roles of Whi2 and Psr1 in Fusarium graminearum remain unclear. In this study, we identified homologous genes of WHI2 and PSR1 in F. graminearum and evaluated their functions by constructing deletion mutants. By comparing the responses of the mutants to different stressors, we found that FgWHI2 and FgPSR1 were involved in responding to osmotic, cell wall and cell membrane stresses, while also affecting the sexual and asexual reproduction in F. graminearum. Our studies demonstrated that FgWHI2 and FgPSR1 regulate the biosynthesis of ergosterol and the transcriptional level of FgCYP51C, which is a CYP51 paralogues unique to Fusarium species. This study also found that the deoxynivalenol (DON) production of FgWHI2 and FgPSR1 deletion mutants was reduced by ≥ 90% and DON production was positively correlated with the transcriptional levels of FgWHI2 and FgPSR1. In addition, we observed that FgWHI2 and FgPSR1 were involved in regulating the sensitivity of F. graminearum to chlorothalonil, fluazinam, azoxystrobin, phenamacril, and oligomycin. This study revealed the existence of cross-resistance between chlorothalonil and fluazinam. chlorothalonil and fluazinam inhibited DON biosynthesis by suppressing the expression of FgWHI2. Interestingly, the subcellular localization of FgWhi2 and FgPsr1 was significantly altered after treatment with chlorothalonil and fluazinam, with increased co-localization. Collectively, these findings indicate that FgWHI2 and FgPSR1 play crucial roles in stress response mechanisms, reproductive processes, secondary metabolite synthesis, and fungicide sensitivity in F. graminearum.