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

Abstract

The high-affinity potassium transporters (HKT) mediate K+-Na+ homeostasis in plants. However, the function of enhancing low-potassium tolerance in sweet potato [Ipomoea batatas (L.) Lam.] remains unrevealed. In this study, a novel HKT transporter homolog IbHKT-like gene was cloned from sweet potato, which was significantly induced by potassium deficiency stress. IbHKT-like overexpressing transgenic roots were obtained from a sweet potato cultivar Xuzishu8 using an Agrobacterium rhizogenes-mediated root transgenic system in vivo. Compared with the CK, whose root cells did not overexpress the IbHKT-like gene, overexpression of the IbHKT-like gene protected cell ultrastructure from damage, and transgenic root meristem cells had intact mitochondria, endoplasmic reticulum, and Golgi dictyosomes. The steady-state K+ influx increased by 2.2 times in transgenic root meristem cells. Overexpression of the IbHKT-like gene also improved potassium content in the whole plant, which increased by 63.8% compared with the CK plants. These results could imply that the IbHKT-like gene, as a high-affinity potassium transporter gene, may play an important role in potassium deficiency stress responses.

Comparative physiological and transcriptome analysis between potassium-deficiency tolerant and sensitive sweetpotato genotypes in response to potassium-deficiency stress

“…K + transporters and K + channels are important factors that contribute to K + uptake and translocation. Our previous studies identified and analyzed the K + transporter and channel gene families in sweetpotato and verified that IbAKT1 and IbHKT1 function in K + absorption [ 8 , 28 ]. HAK5, belonging to the high-affinity uptake system, is the only one capable of supplying K + to the plant under very low external K + conditions [ 29 ].…”

The Role of IAA in Regulating Root Architecture of Sweetpotato (Ipomoea batatas [L.] Lam) in Response to Potassium Deficiency Stress

“…In addition to root morphology, research on the mechanism of low K + tolerance in plants mainly focuses on K + channel proteins (Shaker K + channel family) and K + transporters (KUP/HAK/KT potassium transporter family) in roots. In sweetpotato, it has been reported that IbAKT1 [33] and IbHKT-like [34] may play important roles in the regulation of K + deficiency tolerance in sweetpotato. Whether they have different roles in the two varieties in this experiment, regarding their interaction with root morphology and IAA, is worth further investigation.…”

Transcriptome Characterization and Gene Changes Induced by Fusarium solani in Sweetpotato Roots

“…Studies have also been conducted to identify the key genes induced by other pathogens or abiotic stress tolerance in sweetpotatoes [19][20][21][22][23]. IbBAM1.1, one of the β-amylase genes, acts as a positive regulator to enhance drought and salt stress resistance by regulating the level of osmoprotectants to balance osmotic pressure and activate the scavenging system to maintain reactive oxygen species (ROS) homeostasis in plants [22].…”