Study on the relationship between the hrpZ_(psta) resistance gene expression in transgenic soybean and resistance to gray leaf spot disease

摘要

HrpZ_(psta) gene is a broad spectrum disease resistance gene to plant disease. We transferred it into soybean with the promoter of 35S mediated by Agrobacterium and got T_5 and T_6 transgenic soybean-lines. To study the relationship between hrpZ_(Psta) gene expression in transgenic soybean and the resistance to gray leaf spot disease, we investigated the hrpZ_(psta) gene expression level in T_5 and T_6 transgenic soybean lines of JN29-705-21 and -22 in different tissues by real-time quantitative polymerase chain reaction (qRT-PCR) technique and resistance to gray leaf spot disease by spraying the spore of leaf spot disease. The results showed that the hrpZ_(Psta) gene was expressed in soybean roots, stems, leaves and seeds, the average relative expression levels of T5 two lines were 2.6/2.8, 0.7/0.6, 4.0/4.2, 0.7/0.8, respectively for T_6 were 1.4/1.5, 0.3/0.3, 2.3/2.8, 0.5/0.4; And the resistance level of JN29-705-21 and JN29-705-22 in T_5 and T_6 transgenic lines to gray leaf spot disease were both medium-resistant, whereas the nontransgenic line was susceptible, the disease level of T_5 and T_6 transgenic lines all decreased, the range was from 1-9 of the nontransgenic line to 0-7 of transgenic lines. Correlation analysis showed that the expression levels of hrpZ_(Psta) gene in leaves of each transgenic line in the two generations were very significantly and negatively correlated with the disease level, the correlation coefficient was -0.92/-0.95 in T_5 transgenic lines and -0.91/-0.97 in T_6 transgenic lines respectively, but insignificantly correlated with other tissues. It showed that the higher the target gene expression in leaves was, the lower the disease level was, and the stronger the disease resistant ability becomes. The result indicated the expression of target gene hrpZ_(Psta) was positively correlated with the resistance ability to gray leaf spot, it did improve the disease resistance of soybean plants.