EXPOSURE OF RICE PLANTS TO SILVER NANOPARTICLES AFFECTS THE EXPRESSION OF NAC MULTIFUNCTIONAL GENES

Abstract

Objective: We aimed to evaluate the effect of silver nanoparticles (AgNPs) on the expression of 17 NAC genes in rice plants (Oryza sativa L.) under greenhouse conditions.

Methodology: Twelve-d-old rice seedlings were transferred to a hydroponic system. Fourteen days after the transplant, the following treatments were applied through the nutrient solution: 0, 20, 40 and 80 mg L^-1 AgNPs. Each solution had six repetitions which were distributed in a completely randomized experimental design. From the treated and control plants, total RNA was extracted from stems, from which cDNA was synthesized and a measurement of gene expression was performed by the qRT-PCR technique. The elongation factor 1?, which showed greater stability, was taken as the reference gene. The relative expression of the genes was determined using the 2^-??Ct method, with a differential expression value of 2.

Results: It was found that the AgNPs induced the expression of four NAC genes (Os02g56600, Os07g04560, Os12g43530 and Os06g5107) by at least one dose of AgNPs tested, and one gene (0s08g10080) showed repression of expression by the presence of these nanoparticles in the nutrient solution. In the Os07g04560 gene, the expression was dependent on the concentration of AgNPs, that is, the higher the concentration of AgNPs in the medium, the greater the expression of the gene.

Limitations: In further studies, it would be necessary to explore the expression of more NAC genes in different tissues and phenological stages of the plant.

Conclusions: It is concluded that silver nanoparticles differentially affect the expression of NAC genes in rice, which confirms the multifunctionality of these genes in plants.