Further characterization of an aluminum influx transporter in rice

Nrat1 is a plasma membrane-localized aluminum transporter recently identified in rice, which is a member of Nramp family. Here, we further characterized this transporter in terms of transport substrate specificity. Heterologous assay in yeast showed that Al transport activity by Nrat1 was unaffected by the presence of high concentration of Ca, but significantly inhibited by trivalent ions including Yb and Ga, analogs of Al. Knockout of Nrat1 did not affect the uptake of Cd and Mn in rice. On the other hand, overexpression of Nrat1 led to enhanced Al uptake by rice roots compared with wild-type rice, but did not affect Cd uptake. These results provide further evidence that unlike other Nramp members, Nrat1 is an influx transporter for trivalent Al ion

Genetic effects for maize traits in acid and non-acid soils

Breeding programs for acid-soil tolerance are desirable as a relatively inexpensive and permanent way for increasing maize (Zea mays L.) yield on these soils. Our objective was to compare the genetic effects controlling the expression of maize traits in acid and non-acid soils. Seven related and one unrelated inbred lines, with different levels of tolerance to acid soil, and their F1, F2, BC1, and BC2 generations were evaluated in four acid and two non-acid soils. Estimates of additive, dominance, and epistatic effects were computed for grain yield, plant height, days to mid-silk, and prolificacy, using the generation means analysis procedure. For all traits the major part of the variation was accounted for by additive and dominance effects, with dominance effects being more important than additive and epistatic effects for both acid and non-acid soils. Epistatic effects were significant for some crosses only, being more pronounced for plant height than for the other traits. Furthermore, epistatic effects were randomly distributed among the crosses and were not related to the grain yield of the single-crosses (F1's) and to the genetic relationships of the inbreds in either type of soil. The results suggest that similar pooled gene effects control the expression of the traits assessed in both acid and non-acid soils

Animal geographies II: methods

ArticleAnimal geographies challenge not only the place and placing of the human and the animal but, critically, the methods we use to engage with both in relation. This second review considers the various methodological implications of a more-than-human geography and explores the innovative approaches that animal geographers employ to speak with non-human animals