Drought Resistance Evaluation Of Maize Inbred Lines And Molecular Cloning Of ZmNAC

Maize is one of the three major grain crops in China. Drought is the main determinant of the yield of maize. So breeding the strong drought resistance maize breed is quite significant for maize to adapt to drought and have a stable yield.Identifying and evaluating drought resistance of maize, as well as understanding its physiological property can provide powerful science basis for breeding of drought resistance in maize. Meanwhile, we can try to discover the drought-resistance gene with the help of molecular biological technique and apply it to breeding of drought resistance in maize which can improve the drought resistance ability of maize. NAC transcription factors involved in the metabolic processes of plant growth, but also the response to environmental stresses such as drought.By measuring and analyzing water los rate and relative water content of the maize leaves, this study screens out 15 inbred lines of initial 80 inbred lines, and then measures the contents of proline and MDA, as well as the activity of SOD, CAT and peroxidase. With classifying the drought resistance coefficients of the five indexes, we can evaluate the drought resistance ability of the inbred lines comprehensively. Based on these, this study selects four typical inbred lines and clones the Zm NAC25 genes for each line, and then does the Sequence polymorphism analysis. At the same time, we also do a preliminary analysis for other three NAC genes. Here are the main results:Under the drought stress circumstance, most of the inbred lines exhibit a declining trend of the relative water contents, and water loss rate, proline, MDA, SOD, CAT and peroxidase all have a rising trend.Using Clustar W to compare the Zm NAC25 amino acid sequences which come from different inbred lines, we find that most nucleotide mutations have not caused the changes in amino acid position, and there are only 2 to 5 amino acid position differences among the210 amino acid positions between close inbred lines. It implies the correlation between Zm NAC25 amino acid sequences and the drought resistance in maize inbred lines.Based on constructing expression vector for Zm NAC25, we get the transgenic plants by the method of agrobacterium mediated transformation of arabidopsis thaliana.