The expression pattern of ZmNHX1, ZmHKT1, and ZmMYB30 genes in maize under salinity stress Mir Esmaeil Banifatemeh MSc. Agricultural Biotechnology, Department of Plant Production and Genetics, Faculty of Agriculture and Natural Resources, Urmia University, Urmia, Iran. Email: esmaeilbanifatemeh@yahoo.com Reza Darvishzadeh * Corresponding Author: Professor, Department of Plant Production and Genetics, Faculty of Agriculture and Natural Resources, Urmia University, Urmia, Iran & Professor, Institute of Biotechnology, Urmia University, Urmia, Iran. Email: r.darvishzadeh@urmia.ac.ir. Sorour Arzhang PhD. Student of Plant Breeding-Molecular Genetics and Genetic Engineering, Department of Plant Production and Genetics, Faculty of Agriculture and Natural Resources, Urmia University, Urmia, Iran. Email: sorour.arzhang@gmail.com. Abstract Objective Environmental stresses affect the growth and development of crops during the growing season. Soil salinity is one of the most important environmental stresses that reduce crop yield. Understanding the mechanisms of coping with stress in plants at the molecular level can be effective in providing an efficient way to improve stress-tolerant plants. To save energy, plants do not express all their genes, simultaneously. Rather, depending on environmental conditions, they activate genes that are needed in a particular situation. For instance, in response to salinity stress, the expression of several genes in plants including HKT1 and NHX1 transporters is changed. In this study, variation in the expression of ZmHKT1 and ZmNHX1 genes along with the ZmMYB30 transcription factor were investigated in two salt-tolerant and salt- sensitive maize lines with real time polymerase chain reaction technology. Materials and methods Maize salt-tolerant line (P14L2) and salt-sensitive line (MO17) seeds were grown in plastic pots containing perlite and peat moss in 2:3 ratios under controlled conditions in growth chamber, and