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

摘要

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.