Comparative Methods for Molecular Determination of Host-Specificity Factors in Plant-Pathogenic Fungi

Abstract

Many plant-pathogenic fungi are highly host-specific. In most cases, host-specific interactions evolved at the time of speciation of the respective host plants. However, host jumps have occurred quite frequently, and still today the greatest threat for the emergence of new fungal diseases is the acquisition of infection capability of a new host by an existing plant pathogen. Understanding the mechanisms underlying host-switching events requires knowledge of the factors determining host-specificity. In this review, we highlight molecular methods that use a comparative approach for the identification of host-specificity factors. These cover a wide range of experimental set-ups, such as characterization of the pathosystem, genotyping of host-specific strains, comparative genomics, transcriptomics and proteomics, as well as gene prediction and functional gene validation. The methods are described and evaluated in view of their success in the identification of host-specificity factors and the understanding of their functional mechanisms. In addition, potential methods for the future identification of host-specificity factors are discussed.

Distinctive Gene Expression Profiles and Effectors Consistent With Host Specificity in Two Formae Speciales of Marssonina brunnea

“…The abundant and diverse degrading enzymes make a pathogen infect diverse hosts (Gan et al, 2013;Morris and Moury, 2019). These enzyme expressions and activities affect the pathogenic virulence during an infection (Gan et al, 2013;Ma et al, 2015) and impact host ranges and host specificity (Shirke et al, 2016;Borah et al, 2018;Morris and Moury, 2019). At least the pectate lyase and metalloprotease could play a much crucial role in the pathogenesis of a multigermtubi fungus on the hosts ( Supplementary Table S14; Chen et al, 2015).…”

“…The roles of effectors in host-specific interactions have been evident with more and more demonstrations on genomic comparisons and effector gene functions (Shirke et al, 2016;Inoue et al, 2017;Borah et al, 2018;Morris and Moury, 2019). The absence of putative-secreted effector protein genes made Melanopsichium pennsylvanicum parasitic dicot plants of the Persicaria genus (Sharma et al, 2014).…”

“…The host specificity of a pathogen is becoming a much urgent question to be uncovered in that global climate change will make pathogens jump or broaden their host specificity to become emerging diseases (Poloni and Schirawski, 2016;Inoue et al, 2017;Borah et al, 2018). Gathered evidences suggest that gene expression profiles and virulent factors like effectors could be associated with pathogenic host specificity (Parkinson et al, 2016;Poloni and Schirawski, 2016;Inoue et al, 2017;Palma-Guerrero et al, 2017).…”

“…Gathered evidences suggest that gene expression profiles and virulent factors like effectors could be associated with pathogenic host specificity (Parkinson et al, 2016;Poloni and Schirawski, 2016;Inoue et al, 2017;Palma-Guerrero et al, 2017). However, the determinant mechanism underlying host specificity is still waiting to be elucidated (Borah et al, 2018;Frantzeskakis et al, 2019;Morris and Moury, 2019). Yet most of such knowledge at present has been obtained through documents on strains or formae speciales of pathogens against phylogenetically distant hosts (Borah et al, 2018;Frantzeskakis et al, 2019;Morris and Moury, 2019).…”

“…However, the determinant mechanism underlying host specificity is still waiting to be elucidated (Borah et al, 2018;Frantzeskakis et al, 2019;Morris and Moury, 2019). Yet most of such knowledge at present has been obtained through documents on strains or formae speciales of pathogens against phylogenetically distant hosts (Borah et al, 2018;Frantzeskakis et al, 2019;Morris and Moury, 2019).…”