Molecular Characterization of a Date Palm Vascular Highway 1-Interacting Kinase (PdVIK) Under Abiotic Stresses.

Ibtisam Al-Harrasi,Pannaga Krishnamurthy,Mahmoud W Yaish,Prakash P Kumar,Rashid Al-Yahyai,Ramanjulu Sunkar,Himanshu V Patankar

doi:10.3390/genes11050568

Ibtisam Al-Harrasi, Pannaga Krishnamurthy + Show 5 more

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https://doi.org/10.3390/genes11050568

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Abstract

The date palm (Khalas) is an extremophile plant that can adapt to various abiotic stresses including drought and salinity. Salinity tolerance is a complex trait controlled by numerous genes. Identification and functional characterization of salt-responsive genes from the date palm is fundamental to understand salinity tolerance at the molecular level in this plant species. In this study, a salt-inducible vascular highway 1-interacting kinase (PdVIK) that is a MAP kinase kinase kinase (MAPKKK) gene from the date palm, was functionally characterized using in vitro and in vivo strategies. PdVIK, one of the 597 kinases encoded by the date palm genome possesses an ankyrin repeat domain and a kinase domain. The recombinant PdVIK protein exhibited phosphotyrosine activity against myelin basic protein (MBP) substrate. Overexpression of PdVIK in yeast significantly improved its tolerance to salinity, LiCl, and oxidative stresses. Transgenic Arabidopsis seedlings overexpressing PdVIK displayed improved tolerance to salinity, osmotic, and oxidative stresses as assessed by root growth assay. The transgenic lines grown in the soil also displayed modulated salt response, compared to wild-type controls as evaluated by the overall plant growth and proline levels. Likewise, the transgenic lines exhibited drought tolerance by maintaining better relative water content (RWC) compared to non-transgenic control plants. Collectively, these results implicate the involvement of PdVIK in modulating the abiotic stress response of the date palm.

Highlights

Plant growth and development are directly affected by environmental stresses such as salinity, drought and extreme temperature [1]
The kinases associated with abiotic stress responses in date palm were filtered based on their similarities to the stress-associated kinases of different plant species [48]
Phylogenetic analysis grouped these kinases into ten different classes (Figure 1): the receptor-type protein kinases (RK), including Chitin elicitor receptor protein kinases (CERK) and cysteine-rich receptor-like protein kinases (CRK); the serine/threonine-protein kinases, BSK and PK; the vascular highway 1-interacting kinases (VIK) (MAPK group, 2002); the SNF1-related protein kinases (SnRK); the CBL-interacting serine/threonine-protein kinases (CIPK); the shaggy-related protein kinases (SK); the mitogen-activated protein kinases (MAPK); the endoribonuclease (IRE1a); and the calcineurin

Summary

Introduction

Plant growth and development are directly affected by environmental stresses such as salinity, drought and extreme temperature [1]. Protein kinases are part of the numerous signal transduction pathways participating in the phosphorylation of specific target proteins [11]. STK and HK are the most common types of protein kinases found in plants [14]. In addition to their involvement in various growth and developmental processes, protein kinases play a key role in regulating biotic and abiotic stress responses [11,15].

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