The Liriodendron chinense MKK2 Gene Enhances Arabidopsis thaliana Salt Resistance

Abstract

To adapt and sense environmental perturbations, including a variety of biotic and abiotic stress conditions, plants have developed disparate regulatory pathways. Mitogen-activated protein kinase (MAPK or MPK) signaling cascades are found widespread across the eukaryotic kingdoms of life. In plants, they may regulate signaling pathways aimed at resisting the stressful effects of low temperature, salt damage, drought, touch, and mechanical damage. To date, no conclusive studies into Liriodendron chinense (Hemsl.) Sarg MPK-related stress resistance signaling have been performed. In our study, we cloned three homologous L. chinense MAP kinase kinase family genes: LcMKK2, LcMKK4, and LcMKK6. LcMKK2 and LcMKK6 have their highest expression level in the root, while LcMKK4 is highly expressed in the stem. LcMKK2 showed upregulation in response to salt and cold stress conditions in L. chinense. To further analyze its gene function, we overexpressed LcMKK2 in wild-type Arabidopsis thaliana (L.) Heynh. and obtained transgenic plants. Overexpression of LcMKK2 caused a significant reduction in plant mortality (from 96% to 70%) in response to a 7-day 200 mM NaCl treatment. Therefore, we conclude that LcMKK2 is involved in a signaling response to salt stress, and it could thus prove an effective target gene for breeding strategies to improve Liriodendron salt tolerance.

Precise exogenous insertion and sequence replacements in poplar by simultaneous HDR overexpression and NHEJ suppression using CRISPR-Cas9

“…The importance of the MKK2 gene role in plant protection has been shown against salt (Chen et al, 2020) and low temperature (Gao et al, 2017). In this study, the MKK2 gene was targeted for integrating BleoR into the poplar genome by improving HDR efficiency with Zeocin resistance (Figure 1a).…”

“…In eukaryotic kingdoms, Mitogen-activated protein kinase (MAPK or MPK) signaling is broadly crossed. In plants, they may direct signal pathways to resist the impacts of drought, cold, salt, scratch, and mechanical damage(Chen et al, 2020). Moreover, scientists have shown that MAPKs direct cellular responses against heat shock, osmotic, and other environmental stresses (Mohanta et al, 2015).…”

“…Therefore, our objective was to examine the effects of HDR cofactor overexpression ( CtIP and MRE11 15 ) and simultaneous disruption of NHEJ promoter XRCC4 20 on knock-in efficiency using the MKK2 gene as a case study. Mitogen-activated protein kinases (MAPKs or MPKs) like MKK2 are involved in several key pathways responding to stresses, including disease, drought, cold, heat shock, osmotic, and salt stresses 21,22 .…”

Salt Stress and Plant Molecular Responses

“…Modified genes can be clustered into different types. Some genes are regarded as stress marker genes, and others as ethylene, jasmonic acid, and auxin signaling [47,48].…”

Precise exogenous insertion and sequence replacements in poplar by simultaneous HDR overexpression and NHEJ suppression using CRISPR-Cas9

“…Therefore, our objective was to examine the effects of HDR cofactor overexpression ( CtIP and MRE11 ) [ 15 ] and simultaneous disruption of the NHEJ promoter XRCC4 [ 18 ] on knock-in efficiency using the MKK2 gene as a case study. Mitogen-activated protein kinases (MAPKs or MPKs) like MKK2 are involved in several key pathways responding to stresses, including disease, drought, cold, heat shock, osmotic, and salt stresses [ 23 , 24 ].…”