Genomics Spurs Rapid Advances in Our Understanding of the Biology of Vascular Wilt Pathogens in the Genus Verticillium

Abstract

The availability of genomic sequences of several Verticillium species triggered an explosion of genome-scale investigations of mechanisms fundamental to the Verticillium life cycle and disease process. Comparative genomics studies have revealed evolutionary mechanisms, such as hybridization and interchromosomal rearrangements, that have shaped these genomes. Functional analyses of a diverse group of genes encoding virulence factors indicate that successful host xylem colonization relies on specific Verticillium responses to various stresses, including nutrient deficiency and host defense-derived oxidative stress. Regulatory pathways that control responses to changes in nutrient availability also appear to positively control resting structure development. Conversely, resting structure development seems to be repressed by pathways, such as those involving effector secretion, which promote responses to host defenses. The genomics-enabled functional characterization of responses to the challenges presented by the xylem environment, accompanied by identification of novel virulence factors, has rapidly expanded our understanding of niche adaptation in Verticillium species.

Characterization of the Verticillium dahliae Exoproteome Involves in Pathogenicity from Cotton-Containing Medium

“…A deletion mutant of the Verticillium transcription regulator Vta2 , which controls expression of 125 secreted proteins, failed to colonize plants and induce disease symptoms, indicating a role in pathogenicity (Tran et al, 2014), and the genome of two strains of the vascular wilt fungus V. dahliae , VdLs.17 and JR2, isolated from lettuce and tomato, respectively, have been sequenced (Klosterman et al, 2011; de Jonge et al, 2013). Comparative genomic analyses have also shown that V. dahliae has markedly increased secretion levels of pathogenic factors, including LysM effectors, NLPs, and an Ave1 virulence factor (Klosterman et al, 2011; de Jonge et al, 2012, 2013; Zhou et al, 2012; Santhanam et al, 2013; Klimes et al, 2015), in agreement with previous reports that the purified exoproteome of this pathogen can induce chlorosis and necrosis on the leaves of susceptible plants (Buchner et al, 1982, 1989; Nachmias et al, 1985; Meyer et al, 1994; Mansoori et al, 1995; Davis et al, 1998). These results all suggest that V. dahliae requires the presence of exoproteome virulence factors in order to infect host plants.…”

Salicylic acid-related cotton (Gossypium arboreum) ribosomal protein GaRPL18 contributes to resistance to Verticillium dahliae

“…It then employs various mechanisms to move through the root cortex into the plant vascular system, allowing for further colonization of the plant. When the fungus has completely infected the plant, it produces microsclerotial spores that remain stable and dormant in the soil until they are exposed to a new host [53]. To breed new cotton varieties resistant to Verticillium wilt, more research is required to identify resistance-related genes.…”

Recognition of Verticillium effector Ave1 by tomato immune receptor Ve1 mediates Verticillium resistance in diverse plant species

“…The most prominent soil-borne fungal pathogens comprise Fusarium oxysporum (Michielse and Rep, 2009), Verticillium spp. Klosterman et al, 2009;Klimes et al, 2015) and Rhizoctonia solani (Gonzalez et al, 2011), whereas the most notorious oomycetes include Phytophthora spp. (van West et al, 2003; and Pythium spp.…”

“…Verticillium wilts are vascular wilt diseases caused by soil-borne fungal pathogens that belong to the Verticillium genus Klimes et al, 2015). Although Verticillium wilt symptoms may vary considerably between plant hosts, the most frequently observed symptoms of Verticillium wilt include stunting, wilting, chlorosis, necrosis, vascular discoloration and early senescence .…”

“…Verticillium wilts are vascular wilt diseases that are caused by soil-borne fungi of the genus Verticillium Klimes et al, 2015). This genus comprises ten species of soil-borne fungi that differ in their morphological features, such as resting structures, as well as in their ability to cause plant diseases (Inderbitzin et al, 2011).…”