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

Abstract

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 (Rhizophagus irregularis), potassium application (0, 2, and 8 mM), and drought stress (30% field capacity) on Lycium barbarum growth and potassium status was analyzed. Ten weeks after inoculation, R. irregularis colonized more than 58% roots of L. barbarum seedlings, and increased plant growth as well as potassium content. Potassium application increased colonization rate of R. irregularis, plant growth, potassium content, and decreased root/shoot ratio. Drought stress increased colonization rate of R. irregularis and potassium content. Expression of two putative potassium channel genes in root, LbKT1 and LbSKOR, was positively correlated with potassium content in root and leaves, as well as the colonization rate of R. irregularis. The increased L. barbarum growth, potassium content and genes expression, especially under drought stress, suggested that R. irregularis could improve potassium uptake of L. barbarum root and translocation from root to shoot. Whether AM fungi could form a specific mycorrhizal pathway for plant potassium uptake deserves further studies.

Arbuscular Mycorrhizal Symbiosis Alleviates Salt Stress in Black Locust through Improved Photosynthesis, Water Status, and K+/Na+ Homeostasis

“…Plant biomass production is the most obvious trait reflecting plant performance under abiotic stress and the symbiosis efficiency of AM fungi ( Evelin et al, 2009 ; Ruiz-Lozano et al, 2012 ; Porcel et al, 2016 ; Zhang et al, 2017 ). In the present study, although the dry masses of the shoots and roots of both NM and AM plants were reduced by salt stress, AM plants grew better than NM plants at all salinity levels, which suggests that the AM symbiosis mitigated salt stress in black locust and indicates a high symbiosis efficiency of R .…”

“…They are two major mechanisms that maintain low Na + accumulation in the cytosol ( Deinlein et al, 2014 ). Moreover, class I HKT transporters are involved in removing Na + from the xylem in order to prevent Na + from transport to the leaves ( Sunarpi et al, 2005 ; Davenport et al, 2007 ), while the outward-rectifying K + channel SKOR controls K + loading into the xylem and K + transport to shoots ( Zhang et al, 2017 ).…”

Bioestimulantes via tratamento de sementes na promoção de crescimento de raizes de feijão (Phaseolus vulgaris)

“…A relação entre parte aérea é um atributo importante para plantas superar condições de estresse, como a falta de água. Plantas que com menor relação entre parte aérea e raiz geralmente são mais tolerantes ao estresse por falta de água (XUE et al, 2017;ZHANG et al, 2017 -----------------------------------g vaso -1 ------------------------- Apesar de seu uso difundido nos últimos anos, o efeito de produtos bioestimulantes precisa ser melhor compreendido. Na literatura há resultados divergentes sobre a resposta dos bioestimulantes.…”

The Future Prospects of Arbuscular Mycorrhizal Fungi in Slope Ecological Restoration

“…The promotion of plant nutrient uptake by AMF has received considerable attention over several decades, and the regulation and control mechanisms have been partially determined [46,66,67]. Evidence has shown that AMF could improve the uptake of P [4,32], nitrogen [66], potassium [66], calcium, magnesium, and trace elements, and could contribute to about 70-80% of the P absorbed by hosts.…”