A WRKY-regulated TLP gene mediates the response to cold, drought, and wound stress in jojoba

Thaumatin-like proteins (TLPs) are members of the pathogenesis-related protein 5 (PR5) family and are involved in plant defense mechanisms. Jojoba is an economically important woody oil crop that is tolerant to high temperatures and drought but extremely sensitive to cold stress. To understand the role of ScTLP genes in the stress response of jojoba, we comprehensively analyzed the structure, evolutionary relationships, and functions of ScTLP genes. We identified 24 distinct ScTLP genes in the jojoba genome and organized them into 10 phylogenetic groups. The structures and conserved motifs of these genes showed significant similarities, with four pairs of tandem duplications and four pairs of segmental duplications playing pivotal roles in the expansion of the ScTLP family. Most ScTLP genes feature promoter regions rich in cis-acting elements associated with the stress response and typically exhibit increased expression when exposed to stressors such as cold, drought, and wound stress. Functional analysis of ScTLP11, a member of the stress-responsive ScTLP family, showed that ScTLP11 overexpression results in increased stress resistance in yeast, tobacco, and Arabidopsis. Y1H and luciferase activity assays indicated that ScWRKY41 promoted the expression of ScTLP11 by binding to the W-box elements in the promoter region. Exposure to cold, drought, and wound stress triggered the activation of ScWRKY41 in jojoba leaves, which in turn elevated the expression of ScTLP11. This cascade effect enhances the overall stress resilience of jojoba. Our study contributes to a more complete understanding of the ScTLP gene family and reveals the roles of TLP genes in various stress responses.