Growth medium and conditions for seedlings and fungi
Seeds of wild-type A. thaliana (ecotype Columbia-0), and slim1(Maruyama-Nakashitaet al. , 2006) mutant
were
surface-sterilized for 8 mins in sterilization solution containing lauryl
sarcosine (1%) and Clorix cleaner (23%). Surface-sterilized seeds were
washed with sterilized water 8 times and placed on Petri dishes with MS
medium supplemented with 0.3% gelrite
(Murashige
and Skoog,
1962).
The MS medium contains 1.5 mM MgSO4. After cold
treatment at 4 °C for 48 - 72 hours, plates were incubated at 22 °C
under long day conditions (16 hours light/ 8 hours dark; 80 μmol
m−2 s−1).
Sulfur deficiency assays were performed with MGRL medium
(Fujiwaraet al. , 1992). 1 L of MGRL medium contains 1.75 mM
NaH2PO4, 1.75 mM
Na2HPO4, 2 mM
Ca(NO3)2, 1.5 mM MgSO4,
3 mM KNO3, 67 µM Na2EDTA, 30 µM
H3BO3, 10.3 µM MnSO4,
8.6 µM FeSO4, 1 µM ZnSO4, 1.0 µM
CuSO4, 130 nM CoCl2, 24 nM
(NH4)6Mo7O24,
1% sucrose, 0.3% Gelrite, pH 5.6. For MGRL medium with reduced
sulfate, MgSO4 was replaced by MgCl2.
The total sulfate concentration in high (HS) and low (LS) sulfate MGRL
medium is 1520.9 µM and 20.9 µM, respectively.
Mortierella strains (M. hyalina , FSU-509; M.
alpina , SF002698; M. turficola , SF009851; M. vinacea ,
SF002701; M. longicollis , SF009830) were obtained from Jena
Microbial Resource Center (Jena, Germany). They were grown on
Potato-Dextrose-Agar (PDA), pH 6.5, and at 23 °C in the dark
(Bains
and Tewari, 1987) for fresh subcultures and desiccator assays.
For the sulfur labeling assays, M. hyalina was grown on KM medium
modified from
Hill
and Käfer (2001): 1 L of the medium contains 7.06 mM
NaNO3, 6.98 mM KCl, 11.17 mM
KH2PO4, 177.9 μM
H3BO3, 6.4 μM CuCl2,
76.5 μM ZnCl2, 7.28 μM CoCl2, 0.89 μM
(NH4)6Mo7O24,
29.6 μM MnCl2, 20 μM Na2EDTA, 20 μM
FeCl2, 2% glucose, 0.2% peptone/trypton, 0.1% yeast
extract, 0.1% casein hydrolysate, 1% agar. Finally, 2.11 mM ammonium
sulfate
((NH4)232SO4or
(NH4)234SO4)
was added to make the unlabeled
(32S)/
labeled (34S) medium, respectively.
Tris(methylthio)methane and 34S ammonium sulfate were
purchased from Sigma-Aldrich (Germany).