Construction of a cassava PR protein‐interacting network during Xanthomonas axonopodis pv. manihotis infection

Abstract

Pathogenesis-related (PR) proteins are inducible antimicrobial defence proteins whose specific function in immunity or in other plant processes have not been deeply studied. Genes coding for PRs have been reported in different plant species with numerous homologous proteins belonging to the same functional protein family. Previously some PR candidate genes were identified in response to cassava bacterial blight (CBB) caused by Xanthomonas axonopodis pv. manihotis (Xam): the genes for hevamine (HEV), chitinase (CHI) and sulphite reductase (SiR) were induced in a resistant cassava cultivar during the response to Xam. To understand their functional roles in defence responses, a protein-protein interaction map was generated based on yeast two-hybrid (Y2H) assays of these candidate PR proteins. The results showed that the cassava PRs interact with each other and, although hevamine and chitinase belong to the same class of chitinases, they share only four interactors. Co-regulated expression of PRs and their interactors was observed and similar ontology terms were identified for interactors. Furthermore, an overlap between immune and other metabolic pathways was noticed based on other bioinformatics studies. These results therefore shed more light on the possible function of PR proteins.

Cassava diseases caused byXanthomonas phaseolipv.manihotisandXanthomonas cassavae

“…proteins (Li et al, 2017;Román et al, 2014;Yoodee et al, 2018) and various microRNA families potentially involved in plant defence (Pérez-Quintero et al, 2012). The role of TF families in response to Xpm has been addressed by coexpression network analyses and functional studies by TF families.…”

“…However, challenging susceptible genotypes with Xpm also induces defence‐related genes, but expression is delayed when compared to resistant varieties (López Carrascal et al, 2005 ; Santaella et al, 2004 ). Several studies have identified pathogenesis‐related (PR) proteins (Li et al, 2017 ; Román et al, 2014 ; Yoodee et al, 2018 ) and various microRNA families potentially involved in plant defence (Pérez‐Quintero et al, 2012 ). The role of TF families in response to Xpm has been addressed by coexpression network analyses and functional studies by TF families.…”

Genome-wide analyses of cassava Pathogenesis-related (PR) gene families reveal core transcriptome responses to whitefly infestation, salicylic acid and jasmonic acid

“…In 2006, Antony and Palaniswami [48] showed that PR activities (β-1,3-glucanase, peroxidase and chitinase) increased after B. tabaci infestation. In addition, using yeast two-hybrid assays, Román et al [49] constructed a PR protein-interaction network that is deployed during Xanthomonas infection. We discovered that 37% of the differentially expressed PRs were downregulated (62 genes in cluster 9, Fig.…”

“…Such gene family functional evolution may have occurred in cassava. In fact, the PR network established by Román et al [49] showed that many of the cassava proteins interacting with PRs were associated with abiotic stress or metabolic responses and were not implicated in defense. Additionally, PR proteins regulate cell proliferation/differentiation in tobacco [50] or can rescue of somatic embryos in carrot [51].…”