Function And Molecular Mechanism Analysis Of AetFAMA In Response To Cadmium/salt Stress

FAMA is a bHLH-type transcription factor with a typical helial-loop-helix domain.In Arabidopsis thaliana,FAMA regulates plant immunity to boreal mold and the activity of myrosinase,which can be used as a switch to control cell differentiation during stomatal development and regulate the division of stomatal blast cells.However,the function of FAMA in response to abiotic stress of plant is not fully understood.Aegilops tauschii(DD,2n=14),is the D genome donor of hexaploid wheat,has been a rich source of resistance genes.Till now,the function of FAMA in Aegilops tauschii has not been reported.Our previous study found that AetFAMA was up-regulated under cadmium treatment,demonstrating AetFAMA in response to cadmium stress.To order to explore the function of AetFAMA on abiotic stress tolerance of plant,we cloned AetFAMA and analyzed its function to cadmium and salt tolerance.This study provides a theoretical basis for further understanding the function of AetFAMA to abiotic stress.The following results were obtained:1)The open reading frame of AetFAMA was 1260 bp,encoding 419 amino acids.The molecular weight of AetFAMA was 44.96 k Da;isoelectric point is 5.09;the grand average of hydropathicity(GRAVY)is0.935.AetFAMA protein consists of 149 amino acids(35.56%)in the α-helix region.The amino acids involved in elongation accounted for10.26%(43 amino acids)of the total amino acids.The amino acids in β-sheet region accounted for 4.30% of the total amino acids,with 18 amino acids.There were 209 amino acids involved in the formation of random curling,accounting for 49.88% of the total amino acids.Thus,the secondary structure was mainly composed of α-helix and random curling.Multiple alignments and phylogenetic assay showed that AetFAMA had the highest homology with FAMA from wheat(similarity was 99.78%).2)Subcellular location showed that strong fluorescence signal of AetFAMA-GFP in the nucleus of tobacco leaf cells,suggesting that AetFAMA localized in the nucleus.This result is consistent with the characteristics of general transcription factors..3)To investigated the function of AetFAMA to abiotic stress,Arabidopsis thaliana was transformed by Agrobacterium-mediated method to obtain AetFAMA-overexpressing plants.The phenotypes of the transgenic plants under cadmium and salt stress were analyzed.The root length and germination rate of the transgenic plants were determined respectively,and the physiological and biochemical indexes were determined.Through the analysis of physiological and biochemical indexes,it was found that under cadmium and salt stress,the activity of antioxidant enzymes and the content of antioxidant in Arabidopsis Thaliana plants overexpressing AetFAMA were significantly higher than those of the wild type,suggesting that overexpression of AetFAMA could reduce the accumulation of ROS in plants under cadmium and salt stress,and alleviate cell membrane damage.Therefore,overexpression of AetFAMA can enhance the tolerance of transgenic Arabidopsis thaliana to high salt and cadmium stress.