An isopentenyl transferase transgenic wheat isoline exhibits less seminal root growth impairment and a differential metabolite profile under Cd stress

Cadmium is one of the most important contaminants and it induces severe plant growth restriction. In this study, we analyzed the metabolic changes associated with root growth restriction caused by cadmium in the early seminal root apex of wheat. Our study included two genotypes: the commercial variety ProINTA Federal (WT) and the PSARK::IPT (IPT) line which exhibit high-grade yield performance under water deficit. Root tips of seedlings grown for 72 h without or with 10 μM CdCl2 (Cd-WT and Cd-IPT) were compared. Root length reduction was more severe in Cd-WT than Cd-IPT. Cd decreased superoxide dismutase activity in both lines and increased catalase activity only in the WT. In Cd-IPT, ascorbate and guaiacol peroxidase activities raised compared to Cd-WT. The hormonal homeostasis was altered by the metal, with significant decreases in abscisic acid, jasmonic acid, 12-oxophytodienoic acid, gibberellins GA20, and GA7 levels. Increases in flavonoids and phenylamides were also found. Root growth impairment was not associated with a decrease in expansin (EXP) transcripts. On the contrary, TaEXPB8 expression increased in the WT treated by Cd. Our findings suggest that the line expressing the PSARK::IPT construction increased the homeostatic range to cope with Cd stress, which is visible by a lesser reduction of the root elongation compared to WT plants. The decline of root growth produced by Cd was associated with hormonal imbalance at the root apex level. We hypothesize that activation of phenolic secondary metabolism could enhance antioxidant defenses and contribute to cell wall reinforcement to deal with Cd toxicity.

Instituto de Genética

Fil: Gomez Mansur, Nabila M. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina

Fil: Gomez Mansur, Nabila M. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Fil: Pena, Liliana Beatriz. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina

Fil: Pena, Liliana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Fil: Bossio, Adrian Ezequiel. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; Argentina

Fil: Lewi, Dalia Marcela. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; Argentina

Fil: Beznec, Ailin. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; Argentina

Fil: Blumwald, Eduardo. University of California. Department of Plant Sciences; Estados Unidos

Fil: Arbona, Vicent. Universitat Jaume I. Departament de Ciències Agràries i del Medi Natural, Ecofisiologia i Biotecnologia; España

Fil: Gómez-Cadenas, Aurelio. Universitat Jaume I. Departament de Ciències Agràries i del Medi Natural, Ecofisiologia i Biotecnologia; España

Fil: Benavides, María Patricia. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina

Fil: Benavides, María Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Fil: Gallego, Susana Mabel. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina

Fil: Gallego, Susana Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina