Background
Apple (Malus domestica Borkh.) is an important economic crop. The pathological effects of Fusarium solani, a species complex of soilborne pathogens, on the root systems of apple plants was unknown. It was unclear how mycorrhizal apple seedlings resist infection by F. solani. The transcriptional profiles of mycorrhizal and non-mycorrhizal plants infected by F. solani were compared using RNA-Seq.
Results
Infection with F. solani significantly reduced the dry weight of apple roots, and the roots of mycorrhizal apple plants were less damaged when the plants were infected with F. solani. They also had enhanced activity of antioxidant enzymes and a reduction in the oxidation of membrane lipids. A total of 1839 differentially expressed genes (DEGs) were obtained after mycorrhizal and non-mycorrhizal apple plants were infected with F. solani. A gene ontogeny (GO) analysis showed that most of the DEGs were involved in the binding of ADP and calcium ions. In addition, based on a MapMan analysis, a large number of DEGs were found to be involved in the response of mycorrhizal plants to stress. Among them, the overexpressed transcription factor MdWRKY40 significantly improved the resistance of the apple ‘Orin’ callus to F. solani and the expression of the resistance gene MdGLU by binding the promoter of MdGLU.
Conclusion
This paper outlines how the inoculation of apple seedlings roots by arbuscular mycorrhizal fungi responded to infection with F. solani at the transcriptional level. In addition, MdWRKY40 played an important role in the resistance of mycorrhizal apple seedlings to infection with F. solani.
Fusarium solani has often been isolated from replanted apple roots, suggesting that it is associated with apple replant disease. The mechanism underlying the ability of the mixed cropping of apple trees with Allium fistulosum L. to alleviate apple replant disease remains unclear. The aim of this study was to determine the pathogenicity of the Fusarium solani isolate HBH 08 isolated from diseased roots and the effect of A. fistulosum L. and its root secretions on Fusarium solani isolate HBH 08 and apple seedings. The field experiment showed that A. fistulosum L. not only significantly reduced the amount of the Fusarium solani isolate HBH 08 in replanted soil but also increased the biomass of the grafted apple seedlings. The GC–MS analysis indicated that dimethyl disulphide and diallyl disulphide were active molecules in the root exudates of A. fistulosum L. They inhibited the growth of the Fusarium solani isolate HBH 08 mycelium and decreased the number of spores germinated. In addition, these compounds reduced the amount of the Fusarium solani isolate HBH 08 under replanted conditions and promoted the growth of grafted apple seedlings. Overall, mixed cropping with A. fistulosum L. might be an effective approach for cultivating apple trees and controlling apple replant disease.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.