The bacterial potassium transporter gene MbtrkH improves K+ uptake in yeast and tobacco

Abstract

K + is an essential nutrient for plant growth and is responsible for many important physiological processes. K + deficiency leads to crop yield losses, and overexpression of K + transporter genes has been proven to be an effective way to resolve this problem. However, current research on the overexpression of K + transporter genes is limited to plant sources. TrkH is a bacterial K + transporter whose function generally depends on the regulation of TrkA. To date, whether TrkH can improve K + uptake in eukaryotic organisms is still unknown. In this study, a novel MbtrkH gene was cloned from marine microbial metagenomic DNA. Functional complementation and K +-depletion analyses revealed that MbTrkH functions in K + uptake in the K +-deficient yeast strain CY162. Moreover, K +-depletion assays revealed that MbtrkH overexpression improves plant K + uptake. K + hydroponic culture experiments showed that, compared with WT tobacco lines, MbtrkH transgenic tobacco lines had significantly greater fresh weights, dry weights and K + contents. These results indicate that MbTrkH promotes K + uptake independently of TrkA in eukaryotes and provide a new strategy for improving K +-use efficiency in plants.

A Novel High-Affinity Potassium Transporter IbHKT-like Gene Enhances Low–Potassium Tolerance in Transgenic Roots of Sweet Potato (Ipomoea batatas (L.) Lam.)

“…This confirmed that overexpression of the IbHKT-like gene in sweet potato roots increased K + uptake in K + deficiency conditions. MbtrkH transgenic tobacco lines had significantly greater fresh weights, dry weights, and K + contents compared with WT tobacco lines [ 40 ]. Potassium helps sorghum plants resist drought stress and improves the content of chlorophyll and carotenoids and the activities of SOD, CAT, APX, and nitrogen metabolic enzymes.…”