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. 2020 Sep 21;3(12):e202000878. doi: 10.26508/lsa.202000878

Figure S6. The growth defect of ΔthiA is recovered by co-culture with non-motile mutants.

Figure S6.

(A) We co-cultured an A. nidulans ΔthiA strain with three non-motile B. subtilis strains as follows. MotB; H+-coupled MotA-MotB flagellar stator. FliG; flagellar motor switch protein, physically transduces force from MotA to the rotation of FliF. FliM; flagellar motor switch protein, part of the basal body C-ring. The ΔthiA fungal colony shows a severe growth defect on the plate without thiamine, which is recovered by adding thiamine. The growth defect of ΔthiA is not recovered by co-culture with the non-motile mutants as co-culture with wild-type B. subtilis. Fungal colonies of A. nidulans (ΔthiA) monoculture or co-cultivated with B. subtilis (ΔmotB, ΔfliG, or ΔfliM) on minimal medium with/without thiamine grown for 2 d at 30°C. Each deletion strain expressing ZsGreen. Because flagella are required for bacterial dispersal on the hyphae, the non-motile mutants grow at the center of the fungal colony but do not reach the periphery of the fungal ΔthiA colony (a, right). (B) The area of fungal colonies is measured by ImageJ software. Error bar: SD, n = 3, ***P ≤ 0.001, *P ≤ 0.05. (C) The amount of thiamine in supernatant in the monoculture of B. subtilis non-motile mutants by LC-MS-MRM analysis. OD600 are indicated. B. subtilis non-motile mutants synthesize and secrete thiamine in the medium. (B, C) The growth effect on the fungal ΔthiA colony depends on the secretion amount in the four non-motile B. subtilis strains (B, C). (D) CFU on LB (dilution 10−6) in B. subtilis Δthi monoculture, B. subtilis Δthi + A. nidulans wild-type co-culture, B. subtilis Δthi + A. nidulans ΔthiA co-culture in 200 ml minimal medium with 0.4g shaking at 30°C for 2 and 3 d. CFU in B. subtilis Δthi + A. nidulans wild-type is higher than B. subtilis Δthi monoculture, whereas that in B. subtilis Δthi + A. nidulans ΔthiA co-culture is comparable with B. subtilis Δthi monoculture, suggesting a bi-directional thiamine transfer between B. subtilis and A. nidulans.