The cotton high-affinity Ksup(+) transporter, GhHAK5a, is essential for shoot regulation of Ksup(+) uptake in root under potassium deficiency
2019
Wang, Y. (China Agricultural University, Beijing (China). College of Agronomy and Biotechnology, Department of Crop Physiology and Cultivation, State Key Laboratory of Plant Physiology and Biochemistry) | Wang, Y. | Li, B. | Xiong, C. | Eneji, A.E. | Zhang, M. | Li, F. | Tian, X. | Li, Z.
Potassium (K) deficiency is a key limiting factor in cotton (Gossypium hirsutum) production. By grafting two contrasting cotton cultivars, CCRI41 (more susceptible to Ksup(+) deficiency) and SCRC22 (more tolerant of Ksup(+) deficiency), we established that cotton shoot plays a vital role in the regulation of root Ksup(+) uptake. To identify the genetic basis of this finding, we performed RNA sequencing (RNA-seq) of roots of CCRI41 self-grafts (CCRI41/CCRI41, scion/rootstock) and SCRC22/CCRI41 reciprocal-grafts exposed to Ksup(+) deficiency. We found that GhHAK5a, an orthologous of Arabidopsis thaliana high-affinity Ksup(+) transporter, AtHAK5, was significantly induced in the CCRI41 rootstock by the SCRC22 scion. This gene was mainly expressed in roots and was more highly induced by Ksup(+) deficiency in roots of SCRC22 than those of CCRI41. Agrobacterium-mediated virus-induced gene silencing and yeast complementary assay showed that GhHAK5a is a high-affinity Ksup(+) uptake transporter. Importantly, silencing of GhHAK5a in the CCRI41 rootstock almost completely inhibited the Ksup(+) uptake induced by SCRC22 scion in CCRI41 rootstock. We identified a key high-affinity Ksup(+) transporter, GhHAK5a in cotton, which is the essential target for shoot regulation of root Ksup(+) uptake under Ksup(+) deficiency.
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