AtCIPK16, a CBL-interacting protein kinase gene, confers salinity tolerance in transgenic wheat

Khadija Imtiaz; Moddassir Ahmed; Nazish Annum; Mark Tester; Nasir A Saeed

doi:10.3389/fpls.2023.1127311

AtCIPK16, a CBL-interacting protein kinase gene, confers salinity tolerance in transgenic wheat

Front Plant Sci. 2023 Mar 16:14:1127311. doi: 10.3389/fpls.2023.1127311. eCollection 2023.

Authors

Khadija Imtiaz¹, Moddassir Ahmed¹, Nazish Annum¹, Mark Tester², Nasir A Saeed¹

Affiliations

¹ Wheat Biotechnology Lab, Agriculture Biotechnology Division, National Institute for Biotechnology and Genetic Engineering, Constituent College Pakistan Institute of Engineering and Applied Sciences, Faisalabad, Pakistan.
² Center for Desert Agriculture, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.

Abstract

Globally, wheat is the major source of staple food, protein, and basic calories for most of the human population. Strategies must be adopted for sustainable wheat crop production to fill the ever-increasing food demand. Salinity is one of the major abiotic stresses involved in plant growth retardation and grain yield reduction. In plants, calcineurin-B-like proteins form a complicated network with the target kinase CBL-interacting protein kinases (CIPKs) in response to intracellular calcium signaling as a consequence of abiotic stresses. The AtCIPK16 gene has been identified in Arabidopsis thaliana and found to be significantly upregulated under salinity stress. In this study, the AtCIPK16 gene was cloned in two different plant expression vectors, i.e., pTOOL37 having a UBI1 promoter and pMDC32 having a 2XCaMV35S constitutive promoter transformed through the Agrobacterium-mediated transformation protocol, in the local wheat cultivar Faisalabad-2008. Based on their ability to tolerate different levels of salt stress (0, 50, 100, and 200 mM), the transgenic wheat lines OE1, OE2, and OE3 expressing AtCIPK16 under the UBI1 promoter and OE5, OE6, and OE7 expressing the same gene under the 2XCaMV35S promoter performed better at 100 mM of salinity stress as compared with the wild type. The AtCIPK16 overexpressing transgenic wheat lines were further investigated for their K⁺ retention ability in root tissues by utilizing the microelectrode ion flux estimation technique. It has been demonstrated that after 10 min of 100 mM NaCl application, more K⁺ ions were retained in the AtCIPK16 overexpressing transgenic wheat lines than in the wild type. Moreover, it could be concluded that AtCIPK16 functions as a positive elicitor in sequestering Na⁺ ions into the cell vacuole and retaining more cellular K⁺ under salt stress to maintain ionic homeostasis.

Keywords: CBL-CIPK; CIPK16; K+ homeostasis; MIFE; Wheat; salt tolerance.

Grants and funding

This work was supported by the Center for Desert Agriculture, King Abdullah University of Science and Technology (KAUST), Saudi Arabia, under a collaborative research project (ORS # 2375), and the International Research Support Initiative Program (IRSIP) fellowship to Khadija Imtiaz, Ph.D. scholar, funded by the Higher Education Commission (HEC), Government of Pakistan [IRSIP Fellowship No. (PIN) IRSIP 40, BMS 43].