Rare earth elements lanthanum and gadolinium induce phosphate-deficiencyTI Rare earth elements lanthanum and gadolinium induce phosphate-deficiency responses in Arabidopsis thaliana seedlings

摘要

Aims The aim of this work was to investigate the effects of rare earth elements lanthanum (La3+) and gadolinium (Gd3+) on root system architecture and interactions with low phosphate signaling in Arabidopsis thaliana. Methods Detailed analysis of root system architecture was performed in Arabidopsis WT seedlings and in low phosphorus insensitive mutants lpi1-3 and lpr1-1 lpr2-1 in response to REEs. Expression studies of P-deficiency regulated phosphate transporters AtPT1, AtPT2 and AtMGD2 were also conducted. The role of auxin as a mediator of root morphogenetic changes by Gd3+ was evaluated by using the auxin-inducible marker gene DR5:uidA and auxin-signaling mutants tir1, tir1 afb2 afb3, arf7, arf19 and arf7 arf19. Results We found that increasing concentrations of REEs inhibited primary root growth and increased root hair and lateral root development in WT seedlings. These effects were reduced in low phosphorus insensitive mutants lpi1-3 and lpr1-1 lpr2-1. Gd3+ activated the expression of AtPT1, AtPT2 and AtMGD2 markers. Lateral root formation by Gd3+ decreased in tir1 afb2 afb3 and arf7 arf19 mutants. Conclusions Our results suggest that REEs affect RSA in Arabidopsis by inducing low-P adaptive responses by creating P deficiency conditions in the growth medium by precipitating phosphate.