The miR156/SPL module regulates apple salt stress tolerance by activating MdWRKY100 expression

Abstract

Summary Salt stress dramatically impedes plant growth and development as well as crop yield. The apple production regions are reduced every year, because of the secondary salt damage by improper fertilization and irrigation. To expand the cultivation area of apple (Malus domestica) and select salt‐resistant varieties, the mechanism of salt tolerance in apple is necessary to be clarified. The miR156/SPL regulatory module plays key roles in embryogenesis, morphogenesis, life cycle stage transformation, flower formation and other processes. However, its roles in the mechanisms of salt tolerance are unknown. In order to elucidate the mechanism of 156/SPL regulating salt stress in apple, we performed RLM‐5’ RACE and stable genetic transformation technology to verify that both mdm‐MIR156a and MdSPL13 responded to salt stress in apple and that the latter was the target of the former. MIR156a overexpression weakened salt resistance in apple whereas MdSPL13 overexpression strengthened it. A total of 6094 differentially expressed genes relative to nontransgenic apple plants were found by RNA‐Seq analysis of MdSPL13OE. Further verification indicated that MdSPL13 targeted the MdWRKY100 gene promoter. Moreover, MdWRKY100 overexpression enhanced salt tolerance in apple. Our results revealed that the miR156/SPL module regulates salt tolerance by up‐regulating MdWRKY100 in apple. This study is the first to elucidate the mechanism underlying the miRNA network response to salt stress in apple and provides theoretical and empirical bases and genetic resources for the molecular breeding of salt tolerance in apple.

Comprehensive Analysis of the SBP Family in Blueberry and Their Regulatory Mechanism Controlling Chlorophyll Accumulation

“…These observations indicated that a subset of VcSBP s might be involved in the regulation of chlorophyll accumulation. Previous studies have revealed that SBP family proteins can directly interact with their clients (for example, AtFUL , AtSOC1 , AtDFR , AtAP1 , MdWRKY100 , MaLCYB1.1 , and MaLCYB1.2 , MADS5 , and MADS32 ), thereby regulating diverse biological processes in plants such as flowering, inflorescence formation, biosynthesis of secondary metabolites, root regeneration, and response to stress ( Yamaguchi et al, 2009 ; Gou et al, 2019 ; Ma et al, 2020 ; Zhu et al, 2020 ). However, the targets of SBP proteins associated with chlorophyll accumulation have remained to be found.…”

Response Mechanisms of Plants Under Saline-Alkali Stress

“…Overexpression of the MsWRKY11 gene enhanced salt tolerance in soybean by increasing soluble protein and proline contents and reducing ROS levels, but the detailed regulatory mechanisms remain to be further investigated . MdWRKY100 overexpression enhanced salt tolerance in M. domestica, which was upregulated by the miR156/SPL regulatory module (Ma et al, 2021). MxWRKY64, which is a new WRKY transcription factor gene from Malus xiaojinensis, was induced to express by salt stress in M. xiaojinensis seedlings.…”

Function and Mechanism of WRKY Transcription Factors in Abiotic Stress Responses of Plants

“…The IbWRKY47 gene positively regulates stress resistance-related genes and significantly improves the salt tolerance of Ipomoea batatas [68]. MiR156/SPL modulates salt tolerance by upregulation of Malus domestica salt tolerance gene MdWRKY100 [71]. In Sorghum bicolor, SbWRKY50 could directly bind to the upstream promoter of SOS1 and HKT1 and participate in plant salt response by controlling ion homeostasis [67].…”