The Physiological Mechanism Of Selenium Enhanced Resistance To Sclerotinia Sclerotiorum In Oilseed Rape

In this paper, Zhongshuang 9 and Sclerotinia sclerotiorum was used as experimental materials, soil culture experiments conducted to investigate the pathways of selenium-enhanced resistance to sclerotinia sclerotiorum in oilseed rape, There included the effects of selenium on rape physiology biochemical pathways, plant secondary metabolic pathways, metheds of defense gene expression, and the pathways of mitochondrial ROS. Two selenium application methods were selected: applying Se to soil(0, 0.1, 0.5, 1.0 mg/kg), and leaf spraying selenium(0, 0.1, 0.5, 1.0 mg/L). The main results are as follows: 1. The effects of Se on the incidence of sclerotinia infection and the growth of rape.The results showed that 0.5 mg/kg of Se in soil application or 0.1mg/L of Se in a foliar application promoted the growth of rape and inhibited the growth of sclerotinia sclerotiorum infection. However, without applied selenium or with 1.0mg/L of Se in a foliar application promoted the growth of sclerotinia sclerotiorum infection. 2. The effects of Se on rape physiology biochemical pathways.The results showed that 0.5 mg/kg of Se in soil application inhibited the production of O2·- in leaves, and promoted leaves POD and CAT activity; 0.1mg/L of Se in foliar application inhibited leaves MDA content, but promoted leaves GSH content. 3. The effects of Se on rape plant secondary metabolic pathways.The results showed that 0.5 mg/kg of Se in a soil application increased glucose, citric acid, etc. in the sugar metabolism, promoted functional system stability; guaranteed the stability of the cellular structure by increasing the content of important amino acids, such as valine, glutamate, aspartic acid, tyrosine, histidine etc; enhanced oxidative stress tolerance by increasing the content of antioxidant substance like pyroglutamic acid, GSH and r-aminobutyric acid. 4. The effects of Se on defense gene expression rape of different time periods.The results showed that 0.1 mg/L of Se as a foliar application promoted higher expression of CHI、PDF1.2、NPR1 at 4 days,3 days and 5 days after inoculation of sclerotinia sclerotiorum. The PDF1.2 gene as the upstream gene in the jasmonic acid and ethylene pathways, induced rapeseed defence system opened; the expression of the CHI gene promoted destruction of bacteria cell walls composition; NPR1 adjusted the expression of plant pathogenesis related proteins, adjusting plant acquired resistance system,and inhibited the further infection of sclerotinia sclerotiorum. 5. The effects of Se on mitochondrial ROS pathways in rape.The results showed that 0.5 mg/kg of Se in soil application maintained mitochondrial membrane permeability, and membrane potential stability, inhibited mitochondrial ROS production, and enhanced mitochondrial respiratory chain enzyme activty.