Magnesium and calcium overaccumulate in the leaves of aschengen3mutant ofBrassica rapa

Authors:
Open Access
Publisher website
Google Scholar
Abstract
Magnesium (Mg) and calcium (Ca) are essential mineral nutrients poorly supplied in many human food systems. In grazing livestock, Mg and Ca deficiencies are costly welfare issues. Here, we report a Brassica rapa loss-of-function schengen3 (sgn3) mutant, braA.sgn3.a-1, which accumulates twice as much Mg and a third more Ca in its leaves. We mapped braA.sgn3.a to a single recessive locus using a forward ionomic screen of chemically mutagenized lines with subsequent backcrossing and linked-read sequencing of second back-crossed, second filial generation (BC2F2) segregants. Confocal imaging revealed a disrupted root endodermal diffusion barrier, consistent with SGN3 encoding a receptor-like kinase required for normal formation of Casparian strips, as reported in thale cress (Arabidopsis thaliana). Analysis of the spatial distribution of elements showed elevated extracellular Mg concentrations in leaves of braA.sgn3.a-1, hypothesized to result from preferential export of excessive Mg from cells to ensure suitable cellular concentrations. This work confirms a conserved role of SGN3 in controlling nutrient homeostasis in B. rapa, and reveals mechanisms by which plants are able to deal with perturbed shoot element concentrations resulting from a “leaky” root endodermal barrier. Characterization of variation in leaf Mg and Ca accumulation across a mutagenized population of B. rapa shows promise for using such populations in breeding programs to increase edible concentrations of essential human and animal nutrients.
Funding Information
  • Renewable Industrial Products from Rapeseed (BB/L002124/1)
  • Crop Improvement Research Club
  • Delivering Low-Cost, High-Throughput Root Phenotyping Screens for Arable Crops (BB/J019631/1)
  • BBSRC (BB-G013969-1)
  • BBSRC (BBSSE200613215)
  • Rural and Environment Science and Analytical Services Division
  • Scottish Government
  • Slovenian Research Agency (P1-0212, P1-0112, N7-0077, N1-0105, N1-0090, J7-9418, J7-9398)

This publication has 54 references indexed in Scilit: