Transcriptome changes specifically associated with apple (Malus domestica) root defense response during Pythium ultimum infection

Abstract

RNA-seq technology was applied to identify the transcriptomic changes associated with apple root defense response to Pythium ultimum infection. Genes encoding homolog proteins with functions of pathogen detection such as chitin elicitor receptor kinase (CERK) and wallassociated receptor kinase (WAK) were among the differentially expressed apple genes. The biosynthesis and signaling of several plant hormones including ethylene, jasmonate and cytokinin were specifically induced in response to P. ultimum inoculation. Genes encoding enzymes of secondary metabolisms, cell wall fortification and pathogenesis related (PR) protein, laccase, mandelonitrile lyase and cyanogenic beta-glucosidase were consistently up-regulated in the later stages of infection.

Genes Involved in Stress Response and Especially in Phytoalexin Biosynthesis Are Upregulated in Four Malus Genotypes in Response to Apple Replant Disease

“…They act against pathogens and as scavengers of reactive oxygen species (Börner, 1959;Emmett et al, 2014;Henfrey et al, 2015). An upregulation of flavonol metabolism genes was also found in apple roots under replant conditions (Weiß et al, 2017a;Weiß et al, 2017b) and upon infection with P. ultimum (Shin et al, 2014;Zhu et al, 2014;Shin et al, 2016b;Zhu et al, 2019).…”

“…Phytoalexins like biphenyls and dibenzofurans are known to act in an induced defense mechanism against biotic stressors, such as fungi and bacteria (Ahuja et al, 2012;Chizzali et al, 2012b;Chizzali and Beerhues, 2012;Chizzali et al, 2013). Interestingly, the activation of phytoalexin biosynthesis genes was also found when the plants were inoculated with Pythium ultimum, one component of the ARD complex (Shin et al, 2016b;Zhu et al, 2016). Along with the elevated gene expression, individual phytoalexin compounds were found in higher abundances in roots growing in ARD soils (Weiß et al, 2017b).…”

Apple Replant Disease: Causes and Mitigation Strategies

“…94 hormone metabolism (Shin et al, 2014(Shin et al, , 2016Zhu et al, 2014). Comparative transcriptomic studies of roots of the sensitive rootstock M26 grown either in ARD or gamma irradiated ARD soils revealed several differences in the expression of genes involved in stress responses (Weiß et al, 2017a, b).…”

A Phenotyping Protocol for Detailed Evaluation of Apple Root Resistance Responses Utilizing Tissue Culture Micropropagated Apple Plants

“…[32]. The contrasting resistance responses at this time point may be indicative between resistance and susceptibility for a given genotype.Side by side comparison between genotypes on root necrosis development allowed phenotypic evaluation at root tissue levels.…”