Northeast Forestry University

Soil contamination with Cadmium (Cd) is one of the major environmental issues facing the world, which poses a tremendous threat to plant growth. Heavy-metal ATPase (HMA), essential to regulate plants' metal homeostasis, has been extensively identified in abundant plant species. However, the HMA gene family members in Chrysanthemum indicum have not been identified.

In this study, we identified 10 CiHMAs and classified them into three subfamilies: I, II, and III. Transcriptome and qRT-PCR analyses demonstrated significant induction of CiHMA5 expression under Cd stress. CiHMA5 is situated in the chloroplast and cell membrane. Heterologous expression of CiHMA5 in Arabidopsis thaliana exhibits a Cd-tolerant phenotype with diminished Cd accumulation as well as enhanced antioxidant enzyme activity. Furthermore, CiHMA5 transgenic C. indicum plants also conferred a Cd-tolerant phenotype and lower Cd content, accompanied by higher transfer coefficients in shoots and leaves than wild-type (WT).

These findings established a theoretical groundwork for further delve into the role and regulatory mechanism of CiHMAs in Chrysanthemum under Cd stress.

Woody plants, foundational to terrestrial ecosystems, have evolved sophisticated molecular mechanisms to cope with recurrent drought stress. Post-translational modifications are critical for rapid, dynamic cellular responses, with ubiquitination and SUMOylation serving as key pathways that modulate protein properties to fine-tune drought signaling and adaptation. This review synthesizes recent advances in the ubiquitin and SUMO systems in woody plants under drought. We outline the core components of these two post-translational modification pathways, detail how ubiquitination regulates key transcription factors and abscisic acid (ABA) signaling, and explore the multi-level effects of SUMOylation, from substrate modification to chromatin remodeling, as well as the crosstalk between ubiquitin and SUMO. Furthermore, we specifically discuss and emphasize the distinctive functional roles of ubiquitination and SUMOylation, their evolutionary basis in the context of woody plants' long lifespans and complex developmental processes, and their contributions to adaptation and acclimation mechanisms. By integrating genetic, genomic, and proteomic evidence, this review provides theoretical insights and molecular targets for improving drought resistance in forest trees, thereby supporting research on sustainable forestry and climate change resilience.