Developmental expression of the cucumber Cs-XTH1 and Cs-XTH3 genes, encoding xyloglucan endotransglucosylase/hydrolases, can be influenced by mechanical stimuli

Abstract

The expression of two genes encoding xyloglucan endotransglucosylase/hydrolases (XTHs), Cs-XTH1 and Cs-XTH3, was upregulated during the onset of cucumber somatic embryogenesis. As a means of characterising the developmental regulation of these genes, the activity of the respective upstream regulatory regions was investigated in seedlings and somatic embryos of Arabidopsis thaliana and Cucumis sativus. GUS assays revealed that both genes are under developmental control. In addition, elevated promoter activity was found in the tension-bearing regions of the plant and in response to touch and wounding, which is consistent with the existence of numerous stress-related cis elements in the 5′-regulatory regions. In vivo xyloglucan endotransglucosylase (XET) action assays were performed to gain an overview on the role of XTHs during somatic embryogenesis. The highest XET action was observed in the external cell layers of somatic embryos in the cotyledonary region and in the presumptive region of peg formation. Based on the results, we propose a dual mechanism (one developmental and the second adaptive) for the regulation of Cs-XTH1 and Cs-XTH3 activity wherein the developmental pattern can be modified by mechanical stimuli.

The XTH Gene Family in Schima superba: Genome-Wide Identification, Expression Profiles, and Functional Interaction Network Analysis

“…AtXTH19 also enhances freeze tolerance after cold and subzero acclimation in A. thaliana ( Takahashi et al, 2021 ). The promoter activities and expression of CsXTH1 and CsXTH3 induced by wounding in Cucumis sativus reveal that external mechanical factors play an important role in the regulation of the expression of these genes ( Malinowski et al, 2018 ).…”