Biofortifying food crops with essential minerals would help to alleviate mineral deficiencies in humans. Detection of quantitative trait loci (QTLs) for mineral nutrient contents in rice was conducted using backcross inbred lines derived from an interspecific cross of Oryza sativa × O. rufipogon. The population was grown in Hangzhou and Lingshui, with the contents of Mg, Zn, Fe, Mn, Cu and Se in brown rice measured in both trials and that in milled rice tested in Hangzhou only. A total of 24 QTLs for mineral element contents were identified, including two for both the brown and milled rice, 17 for brown rice only, and five for milled rice only. All the seven QTLs detected for the mineral contents in milled rice and 13 of the 19 QTLs for the contents in brown rice had the enhancing alleles derived from O. rufipogon. Fifteen QTLs were clustered in seven chromosomal regions, indicating that common genetic-physiological mechanisms were involved for different mineral nutrients and the beneficial alleles could be utilized to improve grain nutritional quality by markerassisted selection.
Authors:J. Yao, F. Wang, L. Tian, Y. Zhou, H. Chen, K. Chen, N. Gai, R. Zhuang, T. Maskow, B. Ceccanti, and G. Zaray
Using TAM III multi-channel calorimetry combined with direct microorganism counting (bacteria, actinomycetes and fungi) under
laboratory conditions, we determined the microbial population count, resistance and activity toward cadmium (Cd(II)) and hexavalent
chromium (Cr(VI)) toxicity in soil. The thermokinetic parameters, which can represent soil microbial activity, were calculated
from power-time curves of soil microbial activity obtained by microcalorimetric measurement. Simultaneous application of the
two methods showed that growth rate constant (k), peak-heat output power (Pmax) and the number of living microorganisms decreased with increasing concentration of Cd and Cr. The accumulation of Cr on
E. coli was conducted by HPLC-ICP-MS. Cr6+ accumulation by Escherichia coli was increased steadily with increasing Cr6+ concentration. The results revealed that the change in some thermo-kinetic parameters could have good corresponding relationship
with metal accumulation. Our work also suggests that microcalorimetry is a fast, simple, more sensitive, on-line and in vitro
method that can be easily performed to study the toxicity of different species of heavy metals on microorganism compared to
other biological methods, and can combine with other analytic methods to study the interaction mechanism between environmental
toxicants and microbes.