Dual functions of thermospermine in plant growth and stress responses.

Ectopic expression of a Penicillium oxalicum cyclophilin gene in Arabidopsis thaliana imparts tolerance to cold stress

Molecular Dissection of the SlBAG9 Promoter from Tomato and Its Thermo-Regulatory Activity

The Bcl-2-associated athanogene (BAG) gene family plays vital roles in plant growth, development, and biotic and abiotic stress responses. Previous work has demonstrated that tomato SlBAG9, a group II BAG member, negatively regulates plant thermotolerance. However, the regulatory mechanisms governing SlBAG9 expression remain poorly understood. In this study, we isolated and characterized the authentic 1486 bp full-length promoter (P1) of SlBAG9 from the tomato genome. Building upon our previous transcript-level observations, we provide here a detailed functional characterization of this promoter at the cellular and tissue level. In silico analysis identified several key cis-acting regulatory elements, including abscisic acid-responsive elements (ABRE), anaerobic response elements (ARE), and a heat shock element (HSE1). We used stable transgenic tomato plants carrying SlBAG9pro::GUS to verify that the full-length promoter was capable of driving the expression of β-glucuronidase reporter gene (GUS) in transgenic tomato plants, showing GUS staining was detectable in the roots, stems, leaves, flowers, fruits, and seeds, with the highest activity in red-ripe fruits. Notably, GUS activity was significantly upregulated by high temperature (HT) but not by PEG, NaCl, ABA, or cold treatments. To further dissect the HT-responsive regulatory module, we generated three 5′-terminal deletion fragments (−386 bp, P2; −239 bp, P3; and −113 bp, P4) and fused them to GUS. Under HT stress, the smallest deletion P4 showed negligible GUS activity, whereas P1, P2, and P3 retained significant activity. Furthermore, site-directed deletion of the HSE1 element in the full-length context (MU-P1) abolished HT inducibility, confirming that HSE1 serves as a critical positive HT-responsive element. Collectively, these findings confirm and extend our observations that SlBAG9 is a stress-responsive gene, and the characterized HSE1-dependent promoter module represents a promising candidate for genetic engineering aimed at enhancing thermotolerance in crops.

Heterologous Expression of CsAlaDC Enhances Thermotolerance through a Functional Ethylamine-Theanine-GABA Metabolic Network in Tomato.

Genome-wide analysis of the pectin acetylesterase (PAE) gene family in tomato and SlPAE16 functional characterization associated with pedicel abscission.

Pectin acetylesterase (PAE) regulates pectin acetylation, which affects plant growth, development, and stress tolerance. While their functions are well-defined in models like Arabidopsis, we still know surprisingly little about how they operate in tomatoes (Solanum lycopersicum). We identified 17 SlPAE genes using tomato genome-wide analysis. These genes were classified phylogenetically into three conserved subfamilies, with branch members sharing domain architectures, motifs, and genomic structure. Promoter cis-element analysis identified multiple motifs related to hormone signaling, light response, and stress response. Spatiotemporal expression patterns obtained via qRT-PCR revealed the functional roles of SlPAE genes. Notably, silencing SlPAE16 effectively retarded pedicel abscission, a process mediated by the inhibition of TAPG1/2/4 expression. These findings clarify the functional diversity within the PAE gene family, providing a much-needed framework for future research into their specific biological roles in tomatoes.

Identification of LsPROG gene in Leymus secalinus and validation of its function in Arabidopsis thaliana.

BACKGROUND Leymus secalinus, a perennial grass in the Poaceae family, exhibits multiple stress resistances including drought, salt-alkali, and trampling tolerance, with developed rhizomes enabling adaptation to harsh environments such as sand dunes, thus holding significant value for grassland improvement and forage breeding. RESULTS This study functionally characterized the stress-related LsPROG gene of L. secalinus, revealing that it encoded a 184-amino acid protein. Subcellular localization showed that it was localized to the cell membrane, and contained a conserved zinc-finger domain indicative of potential transcriptional regulatory functions. Using Arabidopsis as a heterologous system, we generated 35S:LsPROG overexpressing Arabidopsis lines. In Arabidopsis transgenic lines, we confirmed that LsPROG significantly promoted lateral root development (about 2-fold) and significantly increased leaf number (by about 1.5-fold at the seedling stage) in transgenic lines compared to the Col-0. Notably, under drought, salt (NaCl), and ABA stresses, the 35S:LsPROG transgenic lines exhibited significantly even more pronounced phenotypic advantages over the Col-0 including improved root system development in seedlings (specifically higher lateral root numbers under drought and enhanced primary root growth under salt/ABA) and better overall plant growth, accompanied by significantly enhanced activities of antioxidant enzymes (SOD increased by 35%, POD increased by 40%). CONCLUSION Through heterologous expression in Arabidopsis, this study systematically unveiled for the first time the pivotal role of LsPROG in plant growth, development, and stress responses, with its functional characteristics elucidated via cross-validation with multiple experimental approaches. These findings lay a critical theoretical foundation for the future breeding of high-quality forage varieties.

A comprehensive exploration of molecular aspects of rice-Ustilaginoidea virens interactions