Strains and culture conditions
Strain Y24
T
was isolated from a cold spring water (E
85°22′ 35″, N 43°50′ 30″) sample by dilution plating on
TYEG agar (10 g tryptone, 5 g yeast extract, 5 g glucose,
3 g K
2
HPO
and 20 g agar in 1,000 ml distilled water, pH
7.0), and incubated at 10 °C for 3 days. Strain H9
4
was
originally isolated from carrot (Daucus carota) on a TYEG
agar plate. The carrot was prepared according to the following
procedure, as described by Li et
al.
(2007).
Carrot was
washed
with tap water,
surface
sterilized with 75
%
ethanol
for
3
min
and 2.6
%
sodium hypochlorite
solution for 5
min
and
75
%
ethanol for 1
min
again,
then rinsed with sterile
double-distilled
water
(ddH
2
T
O). The isolates were routinely
maintained on TYEG agar slants at 4 °C and preserved as
suspensions of cells in glycerol (20 %, v/v) at −80 °C, as
their closely related type strain P. hunanensis FeL05
,
which was obtained from Institute of Agricultural Resources
and Regional Planning, Chinese Academy of Agricultural
Sciences. Biomass for chemotaxonomic and molecular systematic
studies
was
prepared
by
growing
the
strains
in
shake
flasks
(~150
rpm)
of TYEG
broth at 30
°C
for 3
days.
T