Involvement of MdWRKY40 in the defense of mycorrhizal apple against fusarium solani

Abstract

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.

Colonization by orchid mycorrhizal fungi primes induced systemic resistance against a necrotrophic pathogen

“…The presence of a particular OMF in a substrate is a key factor in orchid seedling establishment (Gowland et al, 2013;Pujasatria et al, 2022) to provide the protocorms with nutrients and to protect against stress. We also propose that the ISR in B. striata involves a complex (Fujita et al, 2022;Wang et al, 2022b), but priming could be more variable in orchids than in other plants because orchid diseases also occur on pseudobulbs, rhizomes, and even flowers (Ito and Aragaki, 1977;Swett and Uchida, 2015;. Thus, the priming effects in orchids are still largely unknown if one takes into account pathogen trophic modes, latency, and the attacked organs.…”

“…We also propose that the ISR in B. striata involves a complex mechanism in which regulation of metabolites, defense responses, photosynthesis, and oxidative stress responses is synchronized to reduce D. fangzhongdai proliferation during leaf soft rot onset. Most AM studies have focused on leaves (Fujita et al ., 2022; Wang et al ., 2022b), but priming could be more variable in orchids than in other plants because orchid diseases also occur on pseudobulbs, rhizomes, and even flowers (Ito and Aragaki, 1977; Swett and Uchida, 2015; Li et al ., 2022). Thus, the priming effects in orchids are still largely unknown if one takes into account pathogen trophic modes, latency, and the attacked organs.…”

Apple‐arbuscular mycorrhizal symbiosis confers resistance to Fusarium solani by inducing defense response and elevating nitrogen absorption

“…Chitinase, β‐1,3‐glucanase and phenylalanine ammonia‐lyase (PAL) play an important role in plant disease resistance and can inhibit the growth of pathogens by hydrolyzing fungal cell walls (Tian et al, 2021). PAL, a key and rate‐limiting enzyme in the phenylpropane pathway, synthesizes resistant substances such as lignin and phytoalexin (Wang et al, 2022b). In the mycorrhizal apple rootstocks infected by F. solani , the expression of β‐1,3‐glucanase‐, chitinase‐, and PAL‐encoding genes and various other related genes were significantly increased (Figure 6A).…”

“…The increase in enzyme activity could et al, 2021). PAL, a key and rate-limiting enzyme in the phenylpropane pathway, synthesizes resistant substances such as lignin and phytoalexin (Wang et al, 2022b). In the mycorrhizal apple rootstocks infected by F. solani, the expression of β-1,3-glucanase-, chitinase-, and PAL-encoding genes and various other related genes were significantly increased (Figure 6A).…”

“…Scientist found that although the AMF colonization rates of replanted young apple trees are significantly low compared with non‐replanted, the addition of AMF improves colonization rates and the nutritional status of young apple trees (Despina et al, 2018). AMF impart protective effects if added a few weeks before the pathogen appears (Wang et al, 2022b). Therefore, this study explored the defense response and nitrogen metabolism by the host plant and the AMF action against Fusarium solani after establishing symbiosis with the apple rootstock.…”