Fig. 1: PARP1 exhibited poly(ADP-ribose) polymerase activity and plays an indispensable role in the virulence of M. oryzae.

a The phylogenetic tree and domain architecture of the PARP1 homologs from human, fungi, and plants. ZF, zinc finger domain; BRCT, BRCA1 C-terminal domain; WGR, tryptophan-glycine-arginine domain; HD, helical subdomain; ART, (ADP-ribosyl)transferase domain. The conserved domains were analyzed by Pfam and SMART, and the phylogenetic tree was established by MEGA11. b PARP1 exhibited auto-PARylation activity in vitro. The MBP-PARP1-HA recombinant proteins were expressed and purified from E. coli BL21 (DE3), and incubated in a PARylation buffer at room temperature for 30 mins. The PARylation was analyzed by western blot with α-PAR antibody. c HU-induced PARylation in mycelia. The total protein was extracted from mycelia of wild type after treatment by HU and detected by immunoblot using an α-PAR antibody. d, e PARylation was substantially diminished in Δparp1. Hypha (d), conidia (Co), or appressoria (AP) (e) were collected from the wild type or Δparp1 strain, respectively. The total protein was extracted and detected by immunoblot using an α-PAR antibody. α-β-tubulin immunoblotting or coomassie brilliant blue staining (CBB) was used to visualize loading control. f Virulence difference of the wild-type, Δparp1, and Δparp1-C strains. The spore suspensions were used to inoculate 3-week-old CO39 rice seedlings. Images were obtained 5 days after inoculation, and the lesion sizes were measured and categorized into 5 levels. Bar = 1 cm. g Penetration assay and statistical analysis of infectious hyphal (IH) type in barley leaf cells at 24 hpi (Type I, IH with appressoria formed but no penetration; type II, IH with fewer than three branches; type III, IH with more than three branches; and type IV, IH that fully occupies a plant cell and moves into neighboring cells). One hundred infectious hyphae were assessed for each repeat. Bar = 20 μm. Data in f and g are means ± s.d. from three biological replicates. Statistical analysis was performed by two-way ANOVA followed by Tukey’s test, and the adjusted p values were shown in source data. Data in b and c are representatives of three independent experiments with similar results, and data in d and e are representatives of two independent experiments with similar results.