Regulation of the cell wall integrity by AsSlt2 gene in Alternaria solani

Abstract:

[Background] Potato early blight caused by Alternaria solani is generally considered to be the second major potato disease in potato production, which occurs in various potato production areas. Serious disease will lead to large-scale production reduction and potato block decay during storage, causing huge economic losses to potato production. [Objective] In order to clarify the effect of AsSlt2 gene on the cell wall integrity of Alternaria solani. [Methods] Congo red, sodium dodecyl sulfate (SDS) and cell wall degrading enzymes were applied to evaluate the cell wall integrity for the mutant strain, and calculate the relative growth inhibition rate. RT-qPCR was used to analyze the transcription of cell wall-related genes. The chitin content and extracellular enzyme activity in the cell wall of ΔAsSlt2 were further detected. [Results] the tolerance of ΔAsSlt2 to cell wall stress factors SDS, Congo red and cell wall degradation enzymes were weaker than that of wild and complementation strain. The protoplast release increased significantly after adding cell wall degrading enzyme. Furthermore, it was found that ΔAsSlt2 was more sensitive to exogenous peroxide stress. The extracellular peroxidase and laccase activity of ΔAsSlt2 mutant were significantly reduced, the chitin content in the cell wall of ΔAsSlt2 mutant were decreased. The expression of laccase related genes and chitin synthase related genes in ΔAsSlt2 mutant were detected by RT-qPCR. [Conclusion] The AsSlt2 plays an important role in cell wall integrity and tolerance to external stress in A. solani.