Fig. 4: Rim15-controlled glutaminolysis is required for host rice colonization.
a Plate tests showing growth of strains on minimal media containing the indicated carbon and nitrogen sources. Carbon sources were added at a rate of 1% (w/v). Nitrogen sources were at 10 mM final concentration. Images were taken at 10 days and are representative of at least three independent plates per treatment. For ease of viewing, red arrows indicate morphologically distinct, growth reduced, or absent colonies compared to WT on Gln or Glu media without glucose. b Schematics of glutamine metabolism during the utilization of glutamine as a carbon source via glutaminolysis and anaplerosis in the TCA cycle, during nitrogen assimilation, and during amino acid homeostasis. Proteins identified in the proteomics data and functionally characterized are shown in red. c Glutaminolysis but not nitrogen assimilation is required for rice infection. Rice blast disease symptoms of leaves infected with the indicated strains are shown. GDH2S24A encodes a phospho-null version of Gdh2. GDH2S24D encodes a phospho-mimicking version of Gdh2. For spray assays, spores were applied to 3-week-old rice seedlings of the susceptible cultivar CO-39 at a rate of 1 × 105 spores ml−1. Images were taken at 5 days post inoculation (dpi). For wounded leaf infection assays, equal sized blocks of mycelia were placed on leaves of 3-week-old rice seedlings of the susceptible cultivar CO-39 that had been abraded with a fine needle. Images were taken at 7 dpi. Live-cell imaging of Δglt1 occurred at 44 hpi; white arrowheads indicate appressorial penetration sites, stars indicate movement of IH into neighboring cells, scale bars are 10 µm. Representative images and values are derived from observing 50 infected rice cells per leaf sheath per strain. n = 3 biological replicates. Values are means ± SD. d Plate test images of the indicated strains were taken at 10 days. Gln is minimal media with 1% (w/v) glutamine as the sole carbon and nitrogen source. Glt is minimal media with 1% (w/v) glutamate as the sole carbon and nitrogen source. e Rim15 modulates glutaminolysis via (direct or indirect) Gdh2 phosphorylation to promote host colonization. a, c Source data (including colony diameter statistics) are provided as a Source Data file.
