Biology subjects

Fernandes, T. R.

Publications and source records attributed to Fernandes, T. R..

3 recordsLinked to original sources

bioRxiv2025

Unravelling Induced Resistance in Strawberry: Distinct Metabolomic Signatures Define Cultivar-Specific Resistance to Botrytis cinerea

Botrytis cinerea is a major pathogen in strawberry, and sustainable alternatives to fungicides are needed to manage this disease. Induced resistance (IR) through chemical elicitors represents a promising strategy, but the effectiveness of such compounds remains poorly understood in commercial strawberry (Fragaria x ananassa) cultivars. In this study, we evaluated the efficacy of repeated applications of five elicitors (i.e., {beta}-aminobutyric acid (BABA), (R)-{beta}-homoserine (RBH), indole-3-carboxylic acid (I3CA), jasmonic acid (JA), and salicylic acid (SA)) in three strawberry cultivars (Rowena, Soraya, and Durban). BABA and RBH significantly reduced B. cinerea lesion sizes in Rowena and Soraya, while Durban showed no induced resistance to the elicitors. Untargeted metabolomic profiling of Rowena and Soraya revealed cultivar-specific responses to elicitor treatment and infection, with distinct patterns of metabolite accumulation under both mock- and B. cinerea-inoculated conditions. RBH in Rowena and BABA in Soraya induced the most extensive priming-associated metabolic reprogramming, including enrichment of amino acid, nucleotide, and secondary metabolite pathways such as flavonoids and phenylpropanoids. Significantly, none of the elicitors negatively affected plant growth, flowering, or fruit set. These results demonstrate that the effectiveness and mechanism of IR in strawberries depend on both the elicitor and the cultivar, providing new insights into the metabolomic basis of priming with implications for sustainable disease management in strawberry cultivation.

plant biology↗

bioRxiv2022

Cytosolic pH controls fungal MAPK signaling and pathogenicity

In fungi, ambient pH acts as a key regulator of development and virulence. The vascular wilt pathogen Fusarium oxysporum uses host alkalinization to promote infection of plant hosts through activation of the invasive growth mitogen-activated protein kinase (MAPK) Fmk1. The molecular events underlying pH-driven MAPK regulation are unknown. Using the ratiometric GFP-based pH sensor pHluorin, we find that both F. oxysporum and Saccharomyces cerevisiae respond to extracellular alkalinization or acidification with a transitory shift in cytosolic pH (pHc) and rapid changes in phosphorylation levels of the three fungal MAPKs Fmk1, Mpk1/Slt2 (cell wall integrity) and Hog1 (hyperosmotic stress). Pharmacological inhibition of the essential plasma membrane H+-ATPase Pma1, which leads to pHc acidification, is sufficient to trigger reprogramming of MAPK phosphorylation even in the absence of an extracellular pH shift. Screening of a subset of S. cerevisiae mutants identified the sphingolipid-regulated AGC kinase Ypk1/2 as a key upstream component of pHc-modulated MAPK responses. We further show that acidification of pHc in F. oxysporum leads to an increase of the long chain base (LCB) sphingolipid dihydrosphingosine (dhSph) and that exogenous addition of dhSph activates Mpk1 phosphorylation. Our results reveal a pivotal role of pHc in the regulation of MAPK signaling and suggest new ways to control fungal growth and pathogenicity.

microbiology↗

bioRxiv2020

A homologue of the mammalian tumour suppressor protein PTEN is a functional lipid phosphatase and required for chemotaxis in filamentous fungi

Phosphoinositides (PI) are essential components of eukaryotic membranes and function in a large number of signalling processes. While lipid second messengers are well studied in mammals and yeast, their role in filamentous fungi is poorly understood. We used fluorescent PI-binding molecular probes to localise the phosphorylated phosphatidylinositol species PI[3]P, PI[3,5]P2, PI[4]P and PI[4,5]P2 in hyphae of the endophyte Epichloe festucae in axenic culture and during interaction with its grass host Lolium perenne. We also analysed the roles of the phosphatidylinositol-4-phosphate 5-kinase MssD and the predicted phosphatidylinositol-3,4,5-triphosphate 3-phosphatase TepA, a homologue of the mammalian tumour suppressor protein PTEN. Deletion of tepA in E. festucae and in the root-infecting tomato pathogen Fusarium oxysporum had no impact on growth in culture or the host interaction phenotype. However, this mutation did uncover the presence of PI[3,4,5]P3 in septa of E. festucae and showed that TepA is required for chemotropism in F. oxysporum. The identification of PI[3,4,5]P3 in septa of{Delta} tepA strains suggests that filamentous fungi are able to generate PI[3,4,5]P3 using an alternative biosynthetic pathway and that fungal PTEN homologues are functional lipid phosphatases. The F. oxysporum chemotropism defect demonstrates a conserved role of PTEN homologues in chemotaxis across protists, fungi and mammals.

cell biology↗