Cu/Zn and MnSOD gene expression induced by ethyl methanesulfonate and drought stress in maize

Abstract

Dehydration is one of the most important determinants to plant growth and productivity in general, and maize in particular. Therefore, the current study aimed to induce genetic variation for drought tolerance in two maize inbred lines and their F1 hybrid with aid of ethyl methanesulfonate EMS mutagenesis. Furthermore, the simultaneous effect of EMS was investigated in the expression of MnSOD and Cu/Zn-SOD genes. The study was conducted in the fields of Abu Gharib Station-Agricultural Research Department- Baghdad in the spring season of 2019. The results showed that the genotypes differed significantly in the levels of the expression of both MnSOD and Cu/Zn-SOD genes. The gene pool of 18 and 5 parental lines and their single hybrid (Nahrain) reflected on the expression level of Cu/Zn-SOD gene, that produced 39.54, 17.63 and 24.37 copies, for the three genotypes, respectively at the 7-day irrigation interval. There was an increase in the expression level of the previously mentioned gene in most genotypes at a concentration of 70 mM EMS under the longest irrigation interval (11 days). The plants of inbred 18 were the best at the level of expression of the Cu/Zn-SOD gene with 18.61 copies, followed by the single hybrid and the parental inbred 5 with 11.99 and 7.79 copies, respectively. The investigate genotypes revealed clear differences in the expression of MnSOD gene in response to the two studied factors, as hybrid plants obtained the highest level of gene expression reached 120.59 copies at the EMS concentration of 70 mM and irrigated with the longest interval. It was followed by untreated plants of inbred 18 (control treatment) with 98.33 copies, then inbred 5 which produced 61.92 copies of the same gene at the EMS concentration of 60 mM and under the shorter irrigation interval (7 days). The overall performance of the F1 hybrid and parental line 18 in respect of MnSOD gene expression was nearly identical with 41.83 and 41.81 copies, respectively.