Arbuscular mycorrhizal (AM) fungi can establish a mutualistic relationship with the roots of most terrestrial plants to increase plant nutrient uptake. The effects of potassium uptake and transport by AM symbiosis are much less reported compared to other nutrients. In this research, a heterologous yeast system was used to verify that the LbHAK has capacity for potassium uptake. The split-roots system implemented using seedlings of
Lycium barbarum confirmed that
R. irregularis locally induced
LbHAK expression, which means that
LbHAK is only expressed in mycorrhizal roots. Furthermore, the impacts of overexpression of
LbHAK on the growth, nutrients and water uptake, and transport of mycorrhizal tobacco (inoculation with
Rhizophagus irregularis) at 0.2 mM and 2 mM K conditions were assessed. The mycorrhizal tobacco growth and potassium accumulation were significantly enhanced through
LbHAK overexpression in tobacco. In addition, overexpression of
LbHAK substantially enhanced phosphorus content, while stimulating the expression of
NtPT4,
Rir-AQP1, and
Rir-AQP2 in mycorrhizal tobacco. Moreover,
LbHAK overexpression greatly promoted AM colonization.
LbHAK has a potential role in facilitating potassium absorption through the mycorrhizal pathway, and overexpression of
LbHAK in tobacco may promote the transport of potassium, phosphorus, and water from AM fungi to tobacco. These data imply the important roles played by the
LbHAK in AM-fungi-induced potassium uptake in
L. barbarum and in improving plant nutrients and AM colonization.
Full article