Lanthanum Inhibits Primary Root Growth by Repressing Auxin Carrier Abundances in Arabidopsis

Abstract

Lanthanum (La) is one of rare earth elements that was used as a crop growth stimulants; however, high concentration of La markedly inhibited plant growth. Our previous study indicated that, although La induced the expression of auxin biosynthesis-related genes, it markedly repressed primary root (PR) elongation by reducing auxin accumulation in PR tips. In this study, we exhibited that La reduces the abundances of auxin carriers. Treatment with La markedly inhibited the auxins IAA-, 2,4-D-, and NAA-induced elevation of DR5:GUS activity in the roots, suggesting that La inhibited auxin transport through both the influx and efflux transporters. Supplementation with auxin transport inhibitor naphthylphthalamic acid in La-treated seedlings did not further reduce PR growth compared with that of the La treatment alone, further confirmed that auxin transport is involved in La-induced inhibition of PR growth. Analysis of the protein abundances using the transgenic AUX1-YFP and PIN1/2/4/7-GFP marker lines indicated that La treatment reduced the abundances of all these auxin carriers in the PR tips. La also increased the stabilization of Aux/IAA protein AXR3. Taken together, these results indicated that La treatment inhibits PIN-mediated auxin transport and subsequently impairs auxin distribution and PR growth via reducing auxin carrier abundances.

Low Nitrogen Enhances Nitrogen Use Efficiency by Triggering NO3– Uptake and Its Long-Distance Translocation

“…AUX1 plays an important role in the development of the plant root structure as an IAA input vector. Previous studies in this area focused on the change of root configuration. − The present study further clarified the role of AUX1 in N absorption, especially under −N conditions. Further, we found that AUX1 regulated RSA (Figure a) in a genotype-dependent manner.…”

Interplay between Hormones and Several Abiotic Stress Conditions on Arabidopsis thaliana Primary Root Development

“…The supplementation of La 3+ with NPA, the auxin transport inhibitor, does not further inhibit the PR growth compared with only the La 3+ treatment. However, the PR growth of the mutants of auxin transport pin1 and pin4-3 are less sensitive, while the gain of function axr3-3/iaa17 is more sensitive, to La 3+ application than WT plants [194] ( Figure 3D and Table S2).…”

“…Auxin: La 3+ is a rare-earth metal that inhibits PR growth suppressing auxin transport [194]. La 3+ inhibits the abundance of auxin carriers and reduces auxin accumulation in the PR, by repressing PIN-mediated auxin transport.…”

Synthesis and characterization of a novel lanthanum (III) complex with a di(2-picolyl)amine-based ligand endowed with fluorescent properties

“…1 H NMR (400 MHz, CDCl3) δ 8.54 (ddd, J = 4.9, 1.8, 0.9 Hz, 2H, 6'-Pyr), 7.67 (td, J = 7.6, 1.8 Hz, 3H, 4'-Pyr and CH-Triazole), 7.58 (d, J = 7.8 Hz, 2H, 3'-Pyr), 7.44 -7.33 (m, 5H, Ph), 7.20 -7.15 (m, 2H, 5'-Pyr), 5.53 (s, 2H, CH2-Ph), 3.97 (s, 2H, CH2-Triazole), 3.94 (s, 4H, CH2-Pyr). 13…”

“…Lanthanum is dumped in the environment mainly by petrol-producing industries [12], but it can also be dispersed when household equipment is thrown away improperly [12]. As a result, lanthanum gradually accumulates in soil, water, and plants [1,13,14]; moreover, its presence in the marine ecosystem has been shown to be extremely damaging to a variety of aquatic creatures [15].…”