  Spin susceptibility of stabilized \delta phase in the Pu-Ga alloy is studied
by measuring {69,71}^Ga NMR spectra and nuclear spin-lattice relaxation rate
{69}T_{1}^{-1} in the temperature range 5 - 350 K. The shift ({69}^K) of the
{69,71}^Ga NMR line and {69}^T_{1}^{-1} are controlled correspondingly by the
static and the fluctuating in time parts of local magnetic field arisen at
nonmagnetic gallium due to transferred hyperfine coupling with the nearest f
electron environment of the more magnetic Pu. The nonmonotonic with a maximum
around 150 K behavior of {69}^K(T) \chi_{s,5f}(T) is attributed to the
peculiarities in temperature dependence of the f electron spin susceptibility
\chi_{s,5f}(T) in \delta phase of plutonium. The temperature reversibility
being observed in {69}^K(T) data provides strong evidence for an electronic
instability developed with T in f electron bands near the Fermi energy and
accompanied with a pseudogap-like decrease of \chi_{s,5f}(T) at T<150 K. The
NMR data at high temperature are in favor of the mainly localized character of
5f electrons in \delta phase of the alloy with characteristic spin-fluctuation
energy \Gamma(T) T^{0.35(5)}, which is close to $\Gamma(T) T^{0.5} predicted by
Cox et al. [J. Appl. Phys. 57, 3166 (1985)] for 3D Kondo-system above T_Kondo}.
The dynamic spin correlations of 5f electrons become essential to consider for
{69}^T_{1}^{-1}(T) only at T<100 K. However, no NMR evidences favoring
formation of the static magnetic order in \delta-Pu were revealed down to 5K .
