AUTHOR=Zhang Haoqiang , Wei Suzhen , Hu Wentao , Xiao Longmin , Tang Ming 

TITLE=Arbuscular Mycorrhizal Fungus Rhizophagus irregularis Increased Potassium Content and Expression of Genes Encoding Potassium Channels in Lycium barbarum

JOURNAL=Frontiers in Plant Science

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2017.00440

DOI=10.3389/fpls.2017.00440

ISSN=1664-462X

ABSTRACT=<p>Potassium in plants accounts for up to 10% dry weight, and participates in different physiological processes. Under drought stress, plant requires more potassium but potassium availability in soil solutes is lowered by decreased soil water content. Forming symbiosis with arbuscular mycorrhizal (AM) fungi not only enlarges exploration range of plant for mineral nutrients and water in soil, but also improves plant drought tolerance. However, the regulation of AM fungi on plant root potassium uptake and translocation from root to shoot was less reported. In current study, the effect of an AM fungus (<italic>Rhizophagus irregularis</italic>), potassium application (0, 2, and 8 mM), and drought stress (30% field capacity) on <italic>Lycium barbarum</italic> growth and potassium status was analyzed. Ten weeks after inoculation, <italic>R. irregularis</italic> colonized more than 58% roots of <italic>L. barbarum</italic> seedlings, and increased plant growth as well as potassium content. Potassium application increased colonization rate of <italic>R. irregularis</italic>, plant growth, potassium content, and decreased root/shoot ratio. Drought stress increased colonization rate of <italic>R. irregularis</italic> and potassium content. Expression of two putative potassium channel genes in root, <italic>LbKT1</italic> and <italic>LbSKOR</italic>, was positively correlated with potassium content in root and leaves, as well as the colonization rate of <italic>R. irregularis</italic>. The increased <italic>L. barbarum</italic> growth, potassium content and genes expression, especially under drought stress, suggested that <italic>R. irregularis</italic> could improve potassium uptake of <italic>L. barbarum</italic> root and translocation from root to shoot. Whether AM fungi could form a specific mycorrhizal pathway for plant potassium uptake deserves further studies.</p>