A pqr2 mutant encodes a defective polyamine transporter and is negatively affected by ABA for paraquat resistance in Arabidopsis thaliana

Abstract

Despite the paraquat-resistant mutants that have been reported in plants, this study identified a novel A. thaliana mutant (pqr2) from an XVE inducible activation library based on its resistance to 2 μM paraquat. The pqr2 mutant exhibited a termination mutation in the exon of AT1G31830/PAR1/PQR2, encoded a polyamine uptake transporter AtPUT2/PAR1/PQR2. The PQR2 mutation could largely reduce superoxide accumulation and cell death in the pqr2 plants under paraquat treatment. Moreover, compared with wild type, the pqr2 mutant exhibited much reduced tolerance to putrescine, a classic polyamine compound, which confirmed that PQR2 encoded a defective polyamine transporter. Notably, co-treated with ABA and paraquat, both pqr2 mutant and wild type exhibited a lethal phenotype from seed germination, but the wild type like pqr2 mutant, could remain paraquat-resistance while co-treated with high dosage of Na2WO4, an ABA synthesis inhibitor. Gene expression analysis suggested that ABA signaling should widely regulate paraquat-responsive genes distinctively in wild type and pqr2 mutant. Hence, this study has for the first time reported about ABA negative effect on paraquat-resistance in A. thaliana, providing insight into the ABA signaling involved in the oxidative stress responses induced by paraquat in plants.

polyamine uptake transporter 2 (put2) and decaying seeds enhance phyA-mediated germination by overcoming PIF1 repression of germination

“…PUT2 encodes an amino acid permease family protein and put2 mutants were reported to display resistance to paraquat (PQ), a methyl viologen widely used as a herbicide [24,25]. We found that put2-1 mutants were resistant to PQ, indicating that PUT2 activity is defective in put2-1 mutants (S2A Fig).…”

A novel seed plants gene regulates oxidative stress tolerance in Arabidopsis thaliana

“…Putrescine has a well-documented role in oxidative and abiotic stress tolerance, including drought stress [27]. With regard to PQ-induced oxidative stress, it has been suggested that putrescine competes with PQ for the polyamine transport system, thereby reducing the uptake of PQ [28]. This notion is supported by the discovery that natural variation in the polyamine transporter RMV1 (resistant to methyl viologen 1) determines PQ tolerance in Arabidopsis [29].…”

The Arabidopsis L-Type Amino Acid Transporter 5 (LAT5/PUT5) Is Expressed in the Phloem and Alters Seed Nitrogen Content When Knocked Out

“…The LATs in human function as heteromeric exchangers of large neutral amino acids at 1:1 stoichiometry [4][5][6]10]. However, the Arabidopsis LATs have been demonstrated to have roles in mediating the transport of a range of substrates including amino acid, polyamine, paraquat, and thiamine [11][12][13][14][15][16][17]. The LAT5 was previously studied for its role in developmental responses, such as flowering and senescence, where it was called PUT5 under the assumption that it is a polyamine uptake transporter [18].…”