Vitiligo is an acquired pigmentary disorder and its pathogenesis remains unclear. Oxidative stress is considered to be the initial pathogenic event in the melanocyte destruction. NF-E2-related factor2 (Nrf2) is a transcription factor regulating the expression of detoxifying and antioxidant genes. To investigate the association of the Nrf2 gene promoter polymorphisms with vitiligo in Chinese Han population, the genotypes of -686A ⁄ G, -684G ⁄ A and -650C ⁄ A and the genotyping of variable number of tandem repeat were detected. The data were analysed by the chi-square test and the risk was evaluated by calculating OR and 95% CI. There was statistically significant difference in genotypic and allelic frequencies of -650C ⁄ A between the two groups (P < 0.05). A )650 allele was significantly associated with the risk for vitiligo (OR = 1.724, v 2 = 18.096). Polymorphism of the Nrf2 gene promoter at -650C ⁄ A was associated with the development of vitiligo and A )650 allele may be one of the risk factors.

Protons (H+) in acidic soils arrest plant growth. However, the mechanisms by which plants optimize their biological processes to diminish the unfavorable effects of H+ stress remain largely unclear. Here, we showed that in the roots of Arabidopsis thaliana, the C2H2-type transcription factor STOP1 in the nucleus was enriched by low pH in a nitrate-independent manner, with the spatial expression pattern of NITRATE TRANSPORTER 1.1 (NRT1.1) established by low pH required the action of STOP1. Additionally, the nrt1.1 and stop1 mutants, as well as the nrt1.1 stop1 double mutant, had a similar hypersensitive phenotype to low pH, indicating that STOP1 and NRT1.1 function in the same pathway for H+ tolerance. Molecular assays revealed that STOP1 directly bound to the promoter of NRT1.1 to activate its transcription in response to low pH, thus upregulating its nitrate uptake. This action improved the nitrogen use efficiency (NUE) of plants and created a favorable rhizospheric pH for root growth by enhancing H+ depletion in the rhizosphere. Consequently, the constitutive expression of NRT1.1 in stop1 mutants abolished the hypersensitive phenotype to low pH. These results demonstrate that STOP1-NRT1.1 is a key module for plants to optimize NUE and ensure better plant growth in acidic media.

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Plants use nitrate and ammonium as major nitrogen (N) sources, each affecting root development through different mechanisms. However, the exact signaling pathways involved in root development are poorly understood. Here, we show that, in Arabidopsis thaliana, either disruption of the cell wall-localized ferroxidase LPR2 or a decrease in iron supplementation efficiently alleviates the growth inhibition of primary roots in response to NH4+ as the N source. Further study revealed that, compared with nitrate, ammonium led to excess iron accumulation in the apoplast of phloem in an LPR2-dependent manner. Such an aberrant iron accumulation subsequently causes massive callose deposition in the phloem from a resulting burst of reactive oxygen species, which impairs the function of the phloem. Therefore, ammonium attenuates primary root development by insufficiently allocating sucrose to the growth zone. Our results link phloem iron to root morphology in response to environmental cues.

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