Characteristics of microRNAs and Target Genes in Maize Root under Drought Stress.

Maize (Zea mays) is an important multi-functional crop. The growth and yield of maize are severely affected by drought stress. Previous studies have shown that microRNAs (miRNAs) in maize play important roles in response to abiotic stress; however, their roles in response to drought stress in maize roots is unclear. In our study, we found 375 miRNAs in the roots of 16 inbred lines. Of the 16 lines, zma-MIR168, zma-MIR156, and zma-MIR166 were highly expressed, whereas zma-MIR399, zma-MIR2218, and zma-MIR2275 exhibited low expression levels. The expression patterns of miRNA in parental lines and their derived RILs are different. Over 50% of miRNAs exhibited a lower expression in recombinant inbred lines than in parents. The expression of 50 miRNAs was significantly altered under water stress (WS) in at least three inbred lines, and the expression of miRNAs in drought-tolerant lines changed markedly. To better understand the reasons for miRNA response to drought, the degree of histone modifications for miRNA genes was estimated. The methylation level of H3K4 and H3K9 in miRNA precursor regions changed more noticeably after WS, but no such phenomenon was seen for DNA methylation and m6A modification. After the prediction of miRNA targets using psRNATarget and psRobot, we used correlation analysis and qRT-PCR to further investigate the relationship between miRNAs and target genes. We found that 87 miRNA-target pairs were significantly negatively correlated. In addition, a weighted gene co-expression network analysis using miRNAs, as well as their predicted targets, was conducted to reveal that miR159, miR394, and miR319 may be related to maize root growth. The results demonstrated that miRNAs might play essential roles in the response to drought stress.

Maize DNA Methylation in Response to Drought Stress Is Involved in Target Gene Expression and Alternative Splicing.

DNA methylation is important for plant growth, development, and stress response. To understand DNA methylation dynamics in maize roots under water stress (WS), we reanalyzed DNA methylation sequencing data to profile DNA methylation and the gene expression landscape of two inbred lines with different drought sensitivities, as well as two of their derived recombination inbred lines (RILs). Combined with genotyping-by-sequencing, we found that the inheritance pattern of DNA methylation between RILs and parental lines was sequence-dependent. Increased DNA methylation levels were observed under WS and the methylome of drought-tolerant inbred lines were much more stable than that of the drought-sensitive inbred lines. Distinctive differentially methylated genes were found among diverse genetic backgrounds, suggesting that inbred lines with different drought sensitivities may have responded to stress in varying ways. Gene body DNA methylation showed a negative correlation with gene expression but a positive correlation with exon splicing events. Furthermore, a positive correlation of a varying extent was observed between small interfering RNA (siRNA) and DNA methylation, which at different genic regions. The response of siRNAs under WS was consistent with the differential DNA methylation. Taken together, our data can be useful in deciphering the roles of DNA methylation in plant drought-tolerance variations and in emphasizing its function in alternative splicing.

Enhancing environmental sustainability in transferred farmlands through rural e-commerce: insights from China.

The issue of farmers neglecting environmental concerns in transferred farmlands poses a serious challenge, contradicting the long-term ecological goals of establishing resource-efficient and environment-friendly agriculture. Amidst the pivotal trend of moderately scaled agricultural operations, rural e-commerce holds promise as a catalyst and driving force for enhancing long-term environmental governance of transferred lands. The effectiveness and mechanisms of this potential, however, remain to be empirically examined. This study gathers panel data on environmental positive and negative externalities from six provinces in China, spanning the period from 2013 to 2022, encompassing 6372 farmers. A quasi-natural experiment of farmers' e-commerce participation is designed using difference-in-differences methodology (DID), propensity score matching (PSM), and moderating models. The primary findings are as follows: E-commerce participation increases farmers' positive environmental inputs on transferred lands, such as water-saving irrigation, adoption of social services, and preservation of traditional varieties. Simultaneously, it decreases negative environmental inputs, such as the consumption of fertilizers, pesticides, and agricultural films. The environmental sustainability effects of e-commerce vary across the eastern, central, and western regions of China. E-commerce has a more pronounced impact on agricultural social services and chemical pollutants in the eastern and central regions, while its influence is more significant on water-saving irrigation and variety preservation in the western region. Land transfer forms and supply order contracts do not directly promote farmers' environmentally friendly cultivation practices. Instead, they catalyze the environmental effects of e-commerce through a significant positive interaction term. These conclusions hold after matching for e-commerce participation propensity, while passing sensitivity tests, parallel trend tests, and placebo tests. Consequently, rural e-commerce, without compromising farmers' income, enhances the proactiveness of farmers in environmental conservation, transforms agricultural management practices, and effectively reduces rural non-point source pollution. Policy recommendations include reducing institutional barriers to rural e-commerce participation at the national level, encouraging the establishment of region-specific agricultural environmental sustainability goals, and leveraging the rural e-commerce industry chain to establish a nationwide environmental credit database and incentive mechanism.

Quercetin promotes the apoptosis of fibroblast-like synoviocytes in rheumatoid arthritis by upregulating lncRNA MALAT1.

Rheumatoid arthritis (RA) is a chronic autoimmune joint disease and fibroblast-like synoviocytes (FLS) are the resident mesenchymal cells of synovial joints. Quercetin is a dietary antioxidant. In this study, we aimed to explore the mechanisms responsible for the quercetin-induced apoptosis of FLS from patients with RA (termed RAFLS). RAFLS viability was determined following treatent of the cells with or without quercetin using the Cell Counting kit-8 (CCK-8) assay. The apoptosis of the RAFLS was analyzed using the Annexin V-fluorescein isothiocyanate (FITC) apoptosis detection kit I. The results revealed that RAFLS viability decreased and apoptosis increased in following treatment with quercetin. The differentially expressed long non-coding RNAs (lncRNAs) were screened and marked by PCR array following treatment with quercetin. The expression levels of the screened lncRNAs were then determined and compared in the cells treated with or without quercetin by quantitative PCR. The lncRNA metastasis associated lung adenocarcinoma transcript 1 (MALAT1) was finally selected. Small interfering RNA (siRNA) was then used to knock down the expression of MALAT1 in order to determine the role of MALAT1 in the quercetin-induced apoptosis of RAFLS. The results revealed that the knockdown of MALAT1 inhibited RAFLS apoptosis. At the same time, the expression of caspase-3 and caspase-9 was significantly decreased in the cells in which MALAT1 was knocked down. The phosphoinositide 3-kinase (PI3K)/AKT signaling pathway was activated; this activation is known to be associated with enhanced cell proliferation and decreased apoptosis. The findings of our study indicate that quercetin promotes RAFLS apoptosis by upregulating lncRNA MALAT1, and that MALAT1 induces apoptosis by inhibiting the activation of the PI3K/AKT pathway.

Vascular endothelial growth factor gene polymorphisms and rheumatoid arthritis.

OBJECTIVE: To investigate polymorphisms of the vascular endothelial growth factor (VEGF) gene in patients with rheumatoid arthritis (RA) and their relationship to clinical features. METHOD: A total of 198 unrelated Chinese individuals were enrolled in this study, including 98 patients with RA and 100 healthy controls. Eight different polymorphisms of the VEGF gene were analyzed using Sequenom MassArray platform. RESULT: All 8 polymorphisms were in Hardy-Weinberg equilibrium in controls. The frequencies of rs833070 A allele and rs325010 C allele were elevated in the patients with RA compared with the controls. There were increased genotype frequencies in GA of rs833070, GC of rs3025030, CT of rs3025039 and decreased genotype frequencies in GG of rs833070, GG of rs3025030, CC of rs3025039 in the patients with RA compared with the controls. The frequencies of haplotype GA in rs2010963 and rs833070 were higher in the patients with RA than in the controls. There was no significant difference in the genotype or allele frequencies in the RA group sorted by complications, serum markers, or age of onset. CONCLUSION: Our data suggested a trend of association between VEGF gene polymorphisms and RA, and patients who carried the haplotype GA of rs2010963 and rs833070 were more susceptible to RA. Our study was performed in a small population, and further studies in other populations are needed to confirm these results.

[A study on relationship between single nucleotide polymorphisms of vascular endothelial growth factor gene and susceptibility to systemic lupus erythematosus in China north Han population].

AIM: To investigate relationship between single nucleotide polymorphism(SNP) of VEGF gene and susceptibility to systemic lupus erythematosus(SLE) in China north population. METHODS: Six VEGF SNPs (rs2010963, rs3024994, rs3025000, rs3025010, rs3025035 and rs833070) of forty-four patients with SLE and one hundred healthy controls were examined by Sequenom chip-based MALDI-TOF mass spectomery platform. Different genotypes were analyzed statistically by SPSS 11.5. RESULTS: There was no significant difference between SLE patients and controls in frequency of rs2010963, rs3024994, rs3025000, rs3025010, rs3025035 genotype and allele (P>0.05). The frequency of rs833070 A allele was significantly higher in SLE than that in controls. (31.2% vs 20%, x(2);=4.547, P=0.033, OR=1.818 , 95% CI 1.045-3.162). In the patient with SLE, rs833070 G decreased the susceptibility of arthritis(56% vs 80.4%, x(2);=5.613, P=0.018, OR=0.336, 95% CI 0.134-0.843), while the genotype of rs833070 GG significantly decreased the susceptibility to arthritis(GGvsAG+AA: 28% vs 65.2%, x(2);=6.684, P=0.010, OR=0.207, 95% CI 0.061-0.705). CONCLUSION: VEGF rs833070 A may represent an inreased susceptibility to SLE in China north Han population. VEGF rs833070 G and rs833070 GG may play protective roles in the case of lupus arthritis.

[Relationship between the level of MCP-1 expression in sera of RA patients and ILD].

AIM: To investigate the function and clinical significance of monocyte chemoattractant protein-1 MCP-1 in the pathogenesis of rheumatoid arthritis(RA)and the relation ship between the expression of MCP-1 in serum and interstitial lung disease (ILD) secondary from RA. METHODS: 60 patients with RA were divided into two groups: 30 cases with simple RA group and 30 cases with ILD secondary from RA (RA+ILD group). The control group incuided 20 healthy cases. Enzyme linked immunosorbent assay (ELISA ) was used to determine the serum expression of MCP-1 in patients healthy controls. The differences of MCP-1 level and other laboratory indexes (IgG, IgA, IgM, alpha2-G, gamma-G, RF, ESR, CRP, and the number of arthrocele) in different groups were compared with software spss13.0. RESULTS: The expression of MCP-1 in simple RA patients was significantly higher than that in the control group (P>0.05) and significantly lower than that in the RA+ILD group (P>0.01). The level of MCP-1 in serum of RA patieuts was positively correlated with IgG, IgM, and gamma-G. CONCLUSION: MCP-1 plays an important role in the pathogenesis of RA and may contribute to the promotion of lung fibrosis in ILD secondary from RA.