Simultaneous transcriptome analysis of Colletotrichum gloeosporioides and tomato fruit pathosystem reveals novel fungal pathogenicity and fruit defense strategies

Abstract

The fungus Colletotrichum gloeosporioides breaches the fruit cuticle but remains quiescent until fruit ripening signals a switch to necrotrophy, culminating in devastating anthracnose disease. There is a need to understand the distinct fungal arms strategy and the simultaneous fruit response. Transcriptome analysis of fungal-fruit interactions was carried out concurrently in the appressoria, quiescent and necrotrophic stages. Conidia germinating on unripe fruit cuticle showed stage-specific transcription that was accompanied by massive fruit defense responses. The subsequent quiescent stage showed the development of dendritic-like structures and swollen hyphae within the fruit epidermis. The quiescent fungal transcriptome was characterized by activation of chromatin remodeling genes and unsuspected environmental alkalization. Fruit response was portrayed by continued highly integrated massive up-regulation of defense genes. During cuticle infection of green or ripe fruit, fungi recapitulate the same developmental stages but with differing quiescent time spans. The necrotrophic stage showed a dramatic shift in fungal metabolism and up-regulation of pathogenicity factors. Fruit response to necrotrophy showed activation of the salicylic acid pathway, climaxing in cell death. Transcriptome analysis of C. gloeosporioides infection of fruit reveals its distinct stage-specific lifestyle and the concurrent changing fruit response, deepening our perception of the unfolding fungal-fruit arms and defenses race.

Glycosylated flavonoids: fruit's concealed antifungal arsenal

“…Just after infection, higher b-glucosidase activity was recorded in the RFRS in comparison to the green fruit, which correlated to nine b-glucosidase transcripts that were overexpressed (Fig. Reanalysis of the present authors' previous study (Alkan et al, 2015) revealed that 15 b-glucosidase transcripts from C. gloeosporioides were significantly upregulated during Moreover, b-glucosidase activity increased by 50% from initial colonization (0 dpi) to advanced colonization (7 dpi) (Fig.…”

RNA-seq Transcriptome Response of Flax (Linum usitatissimum L.) to the Pathogenic Fungus Fusarium oxysporum f. sp. lini

“…Calcium dependent genes increased significantly in transcript abundance only 18 DPI (Supplementary Figure S5B). The changes in calcium-related gene response are consistent with physiological measurements of calcium influx upon flax root colonization by F. oxysporum (Olivain et al, 2003), and other fungi (Zhuang et al, 2012; Xiao et al, 2013; Alkan et al, 2015; Serrazina et al, 2015). …”

Alterations in volatile metabolites profile of fresh tomatoes in response to Alternaria alternata (Fr.) Keissl. 1912 infection

“…Alternaria is a necrotrophic phytopathogen fungus that lives quiescently in their host in the cuticular wax or intercellular space until the fruits ripen (Prusky et al, 2013;Alkan et al, 2015). It has the ability to produce cutinases (Trail and Köller, 1993) and penetrate the cuticle, the first structural barrier of fruit defense, and subsequently damages the cell membrane activating lipid peroxidation through the action of enzymes such as phospholipases and lipoxygenase (LOX) (Alkan et al, 2015). Free fatty acids of cuticle or the membrane, are rapidly catabolized by means of β-oxidation, α-oxidation, or the lipoxygenase pathway (Zhao et al, 2014), releasing C 6 volatile compounds such as hexanol, (Z)-3-hexenal, (E)-2-hexenal, or hexanal, among others.…”