Overexpression of a Novel Component Induces HAK5 and Enhances Growth in Arabidopsis

Eri Adams,Ryoung Shin,Celine Diaz,Minami Matsui

doi:10.1155/2014/490252

Abstract

Plants have developed mechanisms to adapt to the potassium deficient conditions over the years. In Arabidopsis thaliana, expression of a potassium transporter HAK5 is induced in low potassium conditions as an adaptive response to nutrient deficiency. In order to understand the mechanism in which HAK5 is regulated, the full-length cDNA overexpressor gene hunting system was employed as a screening method. Of 40 genes recovered, At4g18280 was found to be dramatically induced in response to potassium-deficiency and salt stress. Plants overexpressing this gene showed higher HAK5 expression and enhanced growth. These plants were also less sensitive to potassium-deficiency in terms of primary root growth. Taken together, these data suggest that this novel component, At4g18280, contributes to regulation of HAK5 and, consequently, tolerance to potassium-deficiency in plants.

Highlights

Potassium (K+) is an essential plant macronutrient and the most abundant inorganic cation in higher plants
In order to seek out the components involved in regulation of HIGH-AFFINITY K+ TRANSPORTER5 (HAK5) expression, Arabidopsis plants carrying the HAK5pro::LUC reporter constructs were transformed with Agrobacterium library containing Arabidopsis FOX [13]
An approach combining promoter reporter constructs and the FOX hunting system successfully revealed a list of genes that might be capable of regulating HAK5 expression

Summary

Introduction

Potassium (K+) is an essential plant macronutrient and the most abundant inorganic cation in higher plants. K+deficiency is observed as growth arrest due to a variety of physiological retardations including reduced photosynthesis and impaired phloem transport of sucrose, reviewed in [1,2,3]. In response to K+-deficiency, expression of high-affinity K+ transporters, members of the K+ uptake permease (KUP) family, is induced such as HIGH-AFFINITY K+ TRANSPORTER5 (HAK5) and KUP3 [6, 7] such that the ability to absorb K+ is increased under the limited conditions. Of these transporters, HAK5 is probably the most well-studied high-affinity K+ transporter in Arabidopsis. Molecular mechanisms of plant response to K+deficiency are not well known

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Discussion

Conclusion