Postharvest ASM or Harpin Treatment Induce Resistance of Muskmelons Against Trichothecium roseum

Mitogen-Activated Protein Kinase Cascade and Reactive Oxygen Species Metabolism are Involved in Acibenzolar-S-Methyl-Induced Disease Resistance in Apples

Apple fruits were subjected to dipping treatment to explore the effects of acibenzolar-S-methyl (ASM) and the mitogen-activated protein kinase (MAPK) inhibitor PD98059 on lesion growth in fruits inoculated with Penicillium expansum. We investigated the roles of the MAPK cascade and reactive oxygen species metabolism in disease resistance in apples. ASM treatment inhibited lesion growth; suppressed catalase (CAT) activity; increased H₂O₂ content; reduced glutathione and ascorbic acid contents; and increased glutathione reductase, ascorbate peroxidase, peroxidase, superoxide dismutase, and NADPH oxidase activities. Moreover, ASM upregulated MdSOD, MdPOD, MdGR, MdAPX, MdMAPK4, MdMAPK2, and MdMAPKK1 expressions and downregulated MdCAT and MdMAPK3 expressions. PD98059 + ASM treatment increased CAT activity and MdCAT and MdMAPK3 expressions; inhibited MdSOD, MdPOD, MdGR, MdAPX, MdMAPK4, MdMAPK2, and MdMAPKK1 expressions; reduced superoxide dismutase, peroxidase, ascorbate peroxidase, and glutathione reductase activities; and reduced glutathione content in apples. These findings indicate that ASM induces disease resistance in apples by regulating the expressions of key genes involved in reactive oxygen species metabolism and the MAPK cascade.

Experimental Study on Purification Effect of Biochemical Pool Model for Treatment of Pavement Runoff by Aquatic Plants

The road runoff after rainfall carries a lot of pollutants that could cause great harm to the water environment. A biochemical pool can be used as a treatment for the road runoff. In order to further improve the efficiency of road runoff treatment by biochemical pool and to evaluate the purification effect of the aquatic plants, two aquatic plants of Iris pseudacorus and Myriophyllum verticillatum were chosen in this research. The effect of different planting densities on the treatment of runoff pollutants and the planting mode by different aquatic plants were studied. The results show that both plants have the ability to remove the pollutants like chemical oxygen demand (COD), Zn, Cu, oil, and suspended solids (SS), and the ability is increased with the increase of planting density. The Iris pseudacorus is better than Myriophyllum verticillatum on the removal of Zn, while Myriophyllum verticillatum does better on the removal of Cu, oil, and SS. Combined planting mode can effectively improve the purification effect of COD and petroleum.

Antifungal activity of Lactobacillus plantarum C10 against Trichothecium roseum and its application in promotion of defense responses in muskmelon (Cucumis melo L.) fruit

The antifungal effect of Lactobacillus plantarum C10 on pink rot caused by Trichothecium roseum and its application in muskmelon fruit were investigated. Cell-free supernatant (CFS) produced by Lactobacillus plantarum C10 strongly inhibited the growth of T. roseum and seriously damaged the structures of spores and mycelia of T. roseum. Acid compounds produced by Lb. plantarum C10 were the major antifungal substances and exhibited a narrow pH range from 3.5 to 6.5. Application of the CFS on muskmelon fruit reduced the contamination zone of T. roseum by enhancing the activities of defensive enzymes (phenylalanine ammonialyase, peroxidase and polyphenoloxidase) and promoting the accumulation of phenolics and flavonoids. These results suggested that Lb. plantarum C10 could be used as a biocontrol agent to control pink rot caused by T. roseum in muskmelon fruit.