A heavy metal P-type ATPase OsHMA4 prevents copper accumulation in rice grain

Abstract

Rice is a major source of calories and mineral nutrients for over half the world's human population. However, little is known in rice about the genetic basis of variation in accumulation of copper (Cu), an essential but potentially toxic nutrient. Here we identify OsHMA4 as the likely causal gene of a quantitative trait locus controlling Cu accumulation in rice grain. We provide evidence that OsHMA4 functions to sequester Cu into root vacuoles, limiting Cu accumulation in the grain. The difference in grain Cu accumulation is most likely attributed to a single amino acid substitution that leads to different OsHMA4 transport activity. The allele associated with low grain Cu was found in 67 of the 1,367 rice accessions investigated. Identification of natural allelic variation in OsHMA4 may facilitate the development of rice varieties with grain Cu concentrations tuned to both the concentration of Cu in the soil and dietary needs.

Plastic transport systems of rice for mineral elements in response to diverse soil environmental changes

“…c), suggesting that they are major transporters for Cu uptake in rice roots grown under flooded conditions. OsHMA4 and OsHMA5 , expressed in the root pericycle cells, are involved in vacuolar sequestration and root‐to‐shoot translocation of Cu, respectively (Deng et al , ; Huang et al , ), but their changes in expression between flooded and upland conditions were not large (Figs c, S7c), indicating that they are required for both the soil water conditions. OsYSL16 is involved in Cu distribution (Zheng et al , ), and its expression was upregulated under flooded conditions in nodes, probably in response to low Cu in the soil solution.…”

Natural variation in a molybdate transporter controls grain molybdenum concentration in rice

“…The rice (O. sativa L.) recombinant inbred lines derived from a cross between 'Lemont' (LM, japonica) and 'TeQing' (TQ, indica) (LT-RILs), and 'TeQing'-into-'Lemont' backcross introgression lines (TILs) were described previously (Tabien et al, 2000;Pinson et al, 2012;Huang et al, 2016b). The heterogeneous inbred families (HIFs) of OsMOT1;1 locus were generated as previously described (Tuinstra et al, 1997;Loudet et al, 2005).…”

“…The growth of LT-RIL and TIL populations in the field in Texas, USA, and the growth of the TIL population in a glasshouse in Purdue University were described previously (Zhang et al, 2014;Huang et al, 2016b). For analysis of the grains and different tissues of the WT and osmot1;1, plants were grown in soil in a glasshouse at the University of Aberdeen, UK, as described previously (Huang et al, 2016b). For the hydroponic experiment, WT and osmot1;1 plants were grown in 96well plates with the bottom removed.…”

“…The plates were put in tip boxes containing half-strength Kimura B solution with different concentrations of Mo. The growth condition was described previously (Huang et al, 2016b). A. thaliana transgenic plants were grown on MGRL agar media in a growth chamber at the University of Aberdeen, UK, as described (Huang et al, 2016a).…”

“…The QTL mapping has been performed previously by using both multiple interval mapping and Bayesian information criterion methods based on the least-squares means of the 5 yr replications for the grain Mo of LT-RIL and three replications of TIL (Zhang et al, 2014). We performed new QTL analyses based on the individual year data under flooded or unflooded field conditions using Windows QTL CARTOGRAPHER v.2.5 (http://statgen.nc su.edu/qtlcart/WQTLCart.htm) with a composite interval mapping method according to previous studies (Huang et al, 2016b). Seven markers were developed in the qGMo8 mapping interval and used to genotype the entire population of 123 TILs.…”