Unravelling early events in the Taphrina deformans–Prunus persica interaction: an insight into the differential responses in resistant and susceptible genotypes

Abstract

Leaf peach curl is a devastating disease affecting leaves, flowers and fruits, caused by the dimorphic fungus Taphrina deformans. To gain insight into the mechanisms of fungus pathogenesis and plant responses, leaves of a resistant and two susceptible Prunus persica genotypes were inoculated with blastospores (yeast), and the infection was monitored during 120 h post inoculation (h.p.i.). Fungal dimorphism to the filamentous form and induction of reactive oxygen species (ROS), callose synthesis, cell death and defence compound production were observed independently of the genotype. Fungal load significantly decreased after 120 h.p.i. in the resistant genotype, while the pathogen tended to grow in the susceptible genotypes. Metabolic profiling revealed a biphasic re-programming of plant tissue in susceptible genotypes, with an initial stage co-incident with the yeast form of the fungus and a second when the hypha is developed. Transcriptional analysis of PRs and plant hormone-related genes indicated that pathogenesis-related (PR) proteins are involved in P. persica defence responses against T. deformans and that salicylic acid is induced in the resistant genotype. Conducted experiments allowed the elucidation of common and differential responses in susceptible versus resistant genotypes and thus allow us to construct a picture of early events during T. deformans infection.

The bZIP Transcription Factor LtAP1 Modulates Oxidative Stress Tolerance and Virulence in the Peach Gummosis Fungus Lasiodiplodia theobromae

“…Green bark tissues within 0.5–1.0cm of a wound site were sampled, and immediately placed in liquid nitrogen and stored at −80°C until further analysis. Relative amounts of fungal DNA represented by cycle threshold of L. theobromae internal transcribed spacer 1 (LtITS1) were compared to peach-derived elongation factor 1α ( PpEF1α , reference gene) using the comparative cycle threshold (2 −ΔΔCT ) method ( Svetaz et al, 2017 ). The primers are shown in Supplementary Table S1 .…”

“…Relative amounts of fungal DNA represented by cycle threshold of L. theobromae internal transcribed spacer 1 (LtITS1) were compared to peach-derived elongation factor 1α (PpEF1α, reference gene) using the comparative cycle threshold (2 −ΔΔCT ) method (Svetaz et al, 2017). The primers are shown in Supplementary Table S1.…”

Insights into the Transcriptional Reprogramming of Peach Leaves Inoculated with Taphrina deformans

“…The fungus in its biotrophic filamentous phase is characterized by septate hyphae and is exclusively found in host tissues as an obligate parasitic form, while its yeast stage is observed in the saprophytic phase [ 6 ]. During the initial stages of infection, T. deformans enters the host cells through the stomata and stimulates host cell growth and division [ 7 ]. Even though the exact mechanisms concerning tumour development are still unclear, it was proposed that the infection causes a hormonal imbalance in the host, leading to the formation of tumours as T. deformans synthetizes and excretes auxins and cytokinins [ 8 ].…”

“…As a result, only two days after infection did the T. deformans yeast cells turn into their filamentous form, whereas the majority of the U. maydis haploid sporidia were able to infect maize after 12 HAI by forming hyphae and developing appressoria [ 11 ]. Furthermore, in the peach– T. deformans pathosystem, early host responses are not observed earlier than around 12 h after infection [ 11 ], while it was reported that the filamentous form of T. deformans is adequately developed in peach leaves after inoculation with blastospores in the yeast phase of the pathogen [ 7 ]. The identification of peach genes and pathways conferring tolerance to the fungus has proven to be a challenging task because of the complex molecular interactions that occur between the pathogen and the host cells in the apoplast [ 7 ].…”

Characterization, Expression Profiling, and Functional Analysis of PtDef, a Defensin-Encoding Gene From Populus trichocarpa

“…SA induces the expression of pathogenesis-related protein (PR), resulting in initiation of the HR. SA promotes the acquisition of resistance by accumulation of PR protein and ROS, and can be transported in plants (Cui et al, 2017;Svetaz et al, 2017). The non-expresser of physically related protein 1 (NPR1) is the dominant regulator of plant disease resistance.…”