![]() ![]() In fungi, manganese deficiency has been shown to result in alterations in hyphal morphology and reduction of sporulation. The availability of manganese for the cell is therefore essential. It serves as a cofactor for the reactions catalysed by metalloproteins including DNA and RNA polymerases, peptidases, carboxylases, superoxide dismutase, sugar transferases and the water oxidation complex in photosystem II (reviewed by Reddi et al. Manganese is a trace element that is essential for all organisms. niger, and manipulation of its expression modulates citric acid overflow. ![]() Our results demonstrate that dmtA is physiologically important in the transport of Mn 2+ ions in A. The Y p/s of the overexpressing strain was 17% of that of the parent strain, irrespective of the concentrations of external Mn 2+. This yield was reduced only by 20% in the presence of 100 µg L −1 Mn 2+, whereas production by the parent strain was reduced by 60%. Growth of both the parent and the deletion strains under citric acid producing conditions resulted in molar yields (Y p/s) of citric acid of > 0.8, although the deletion strain produced ~ 30% less biomass. Deletion of dmtA caused defects in germination and hyphal morphology even in the presence of 100 µg L −1 Mn 2+, while overexpression of dmtA led to enhanced germination and normal hyphal morphology at limiting Mn 2+ concentration. Cultivation of the parent strain under Mn 2+ ions limitation conditions (5 µg L −1) reduced germination and led to the formation of stubby, swollen hyphae that formed compact pellets. Compared to the parent strain, overexpression of dmtA increased Mn 2+ intake at both low and high external Mn 2+ concentrations. niger eliminated the intake of Mn 2+ at low (5 µg L −1) external Mn 2+ concentration, and reduced the intake of Mn 2+ at high (> 100 µg L −1) external Mn 2+ concentration. niger gene ( dmtA NRR元_07789), predicted to encode a transmembrane protein, with high sequence identity to the yeast manganese transporters Smf1p and Smf2p. To this end, we investigated transport of Mn 2+ ions in A. niger is therefore of critical importance to citric acid production. A requirement for high-yield citric acid production is keeping the concentration of Mn 2+ ions in the medium at or below 5 µg L −1. 132, 618–628 10.1104/pp.103.Citric acid, a commodity product of industrial biotechnology, is produced by fermentation of the filamentous fungus Aspergillus niger. Genomic comparison of P-type ATPase ion pumps in Arabidopsis and rice. Variation in molybdenum content across broadly distributed populations of Arabidopsis thaliana is controlled by a mitochondrial molybdenum transporter (MOT1). C., Buchner P., Lahner B., Danku J., et al. The rice mitochondrial iron transporter is essential for plant growth. 14, 1845–1853īashir K., Ishimaru Y., Shimo H., Nagasaka S., Fujimoto M., Takanashi H., et al. Molecular identification of an ABC transporter complex for manganese: analysis of a cyanobacterial mutant strain impaired in the photosynthetic oxygen evolution process. Manganese deficiency in Chlamydomonas results in loss of photosystem II and MnSOD function, sensitivity to peroxides, and secondary phosphorus and iron deficiency. Such knowledge would vastly improve our understanding of plant Mn homeostasis.Īrabidopsis manganese metal transport rice synchrotron x-ray fluorescence.Īllen M. A combination of techniques including mutant analysis and Synchrotron X-ray Fluorescence Spectroscopy can assist in identifying essential transporters of Mn. These transporter families include NRAMP (natural resistance associated macrophage protein), YSL (yellow stripe-like), ZIP (zinc regulated transporter/iron-regulated transporter -related protein), CAX (cation exchanger), CCX (calcium cation exchangers), CDF/MTP (cation diffusion facilitator/metal tolerance protein), P-type ATPases and VIT (vacuolar iron transporter). Several gene transporter families have been implicated in Mn transport in plants. Despite the importance of Mn in plant development, relatively little is known about how it traffics between plant tissues and into and out of organelles. Mn deficiency is most prominent on alkaline soils with approximately one third of the world's soils being too alkaline for optimal crop production. Mn deficient plants exhibit decreased growth and yield and are more susceptible to pathogens and damage at freezing temperatures. In plants, Mn serves as a cofactor in essential processes such as photosynthesis, lipid biosynthesis and oxidative stress. Manganese (Mn), an essential trace element, is important for plant health.
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