Characterisation of lanthanum toxicity for root growth of Arabidopsis thaliana from the aspect of natural genetic variation
कीवर्ड
सार
The mechanism of lanthanum (La3+) toxicity on root growth of Arabidopsis was studied by physiological and genetic approaches using Landsberg erecta (Ler) × Columbia (Col) recombinant inbred lines (RILs) and other natural accessions. Quantitative trait locus (QTL) analyses revealed regulation of La3+ tolerance of the Ler × Col RILs by multiple genetic factors consisted of three significant QTLs and seven epistatic interacting loci pairs. The La content in the root tip was not correlated with La3+ tolerance in the RILs, indicating that the observed La3+ rhizotoxicity was not related to direct toxicity of La3+ in the symplast. The La3+ tolerance of root growth in the RILs was not correlated with Al3+ and Cu2+ tolerances, but was correlated with tolerances for other rare earth elements, including Gd3+, a known Ca2+ channel antagonist, and verapamil, a Ca2+ channel blocker. The genetic architecture of verapamil tolerance in root growth, which was identified by QTL analysis, was closely related to that of La3+ tolerance. La3+ tolerance and verapamil tolerance or Gd3+ tolerance in natural accessions of Arabidopsis also showed a positive correlation. These results indicate that the major La3+ toxicity on the root growth of Arabidopsis may involve its action as a Ca2+ channel antagonist.