CCR4-Not Complex Subunit Not2 Plays Critical Roles in Vegetative Growth, Conidiation and Virulence in Watermelon Fusarium Wilt Pathogen Fusarium oxysporum f. sp. niveum

Abstract

CCR4-Not complex is a multifunctional regulator that plays important roles in multiple cellular processes in eukaryotes. In the present study, the biological function of FonNot2, a core subunit of the CCR4-Not complex, was explored in Fusarium oxysporum f. sp. niveum (Fon), the causal agent of watermelon wilt disease. FonNot2 was expressed at higher levels in conidia and germinating conidia and during infection in Fon-inoculated watermelon roots than in mycelia. Targeted disruption of FonNot2 resulted in retarded vegetative growth, reduced conidia production, abnormal conidial morphology, and reduced virulence on watermelon. Scanning electron microscopy observation of infection behaviors and qRT-PCR analysis of in planta fungal growth revealed that the ΔFonNot2 mutant was defective in the ability to penetrate watermelon roots and showed reduced fungal biomass in root and stem of the inoculated plants. Phenotypic and biochemical analyses indicated that the ΔFonNot2 mutant displayed hypersensitivity to cell wall perturbing agents (e.g., Congo Red and Calcofluor White) and oxidative stress (e.g., H2O2 and paraquat), decreased fusaric acid content, and reduced reactive oxygen species (ROS) production during spore germination. Our data demonstrate that FonNot2 plays critical roles in regulating vegetable growth, conidiogenesis and conidia morphology, and virulence on watermelon via modulating cell wall integrity, oxidative stress response, ROS production and FA biosynthesis through the regulation of transcription of genes involved in multiple pathways.

Role of the Citrus sinensis RNA deadenylase CsCAF1 in citrus canker resistance

“…Orthologues of the yeast CAF1 and NOT proteins have now been identified in virtually all eukaryotes (Dai et al , ; Dupressoir et al , ; Nousch et al , ; Temme et al , ; Winkler and Balasco, ). Nevertheless, in contrast to yeast and animals, the role played by CAF1 proteins in plants is less clear.…”

A Cerato-Platanin Family Protein FocCP1 Is Essential for the Penetration and Virulence of Fusarium oxysporum f. sp. cubense Tropical Race 4

“…The wild-type strain and transformants generated in this study were grown at 28 °C on PDA for mycelial growth tests. MBL broth was used for conidiation assays [49].…”

“…The disease index range was as follows: 0 (no symptoms), 1 (some brown spots in the inner rhizome), 2 (less than 25% of the inner rhizome showed browning), 3 (up to 3/4 of the inner rhizome showed browning), and 4 (entire inner rhizome and pseudostem were dark brown, dead). In addition, the penetration behaviour of the strains was examined on cellophane membranes using a previously described protocol [49].…”

“…To estimate and compare the fungal biomass inside the plant, banana roots were collected at 5, 10, and 15 dpi and the transcript levels of the FocEF1α and banana MusaActin genes were determined by qRT-PCR using a pair of FocEF1α -specific primers and a pair of banana MusaActin -specific primers (Table S2). The relative fungal biomass was calculated by normalizing FocEF1α to banana MusaActin , shown as the ratio of FocEF1α/MusaActin [49].…”

“…AAA group) plantlets with six to seven leaves were inoculated by dipping the roots into a Foc spore suspension (1 × 10 7 spores/L) on a rotary shaker at 80 rpm and root samples were collected 48 h later. The root samples were treated as described previously [49] and observed using a Hitachi Model S-3400N scanning electron microscope (Hitachi, Tokyo, Japan).…”