Heat shock transcription factors (HSFs) have long been recognized for their essential role in mediating thermotolerance via the activation of heat shock proteins (HSPs). Recent studies, however, have significantly broadened this view, revealing that HSFs function as versatile transcriptional regulators orchestrating plant adaptation to a wide range of abiotic and biotic stresses. This review synthesizes current knowledge of HSF structure, activation, and canonical roles in the heat shock response, while emphasizing emerging insights into their diverse functions beyond heat stress. Evidence from both model and crop species demonstrates that many HSFs confer tolerance to a broad range of stresses, including drought, cold, salinity, oxidative stress, and pathogen attack, through intricate crosstalk with hormonal (e.g., ABA, SA, JA) and redox signaling pathways, as well as MAPK-mediated phosphorylation. We also discuss biotechnological strategies such as CRISPR/Cas-mediated genome editing, stress-inducible promoter engineering, and synthetic transcriptional circuits that offer promising avenues for fine-tuning HSF expression and enhancing multi-stress resilience in crops. A deeper understanding of HSF multifunctionality not only advances our comprehension of plant stress biology but also provides a foundation for engineering resilient crops in the context of global climate change.

Cold stress adversely impacts tomato (Solanum lycopersicum) production, particularly in temperate regions, by impairing growth, development, and yield. Abscisic acid (ABA), a key phytohormone, plays a central role in mediating tomato’s response to cold stress through a complex crosstalk network with other hormones and signaling molecules. This review examines ABA’s interactions with hormones such as ethylene, jasmonates, auxin, gibberellins, salicylic acid, brassinosteroids, and strigolactones, as well as signaling molecules like hydrogen peroxide, nitric oxide, hydrogen sulfide, and calcium. These interactions regulate various physiological processes, including osmolyte accumulation, membrane stability, and oxidative stress mitigation, and influence the expression of cold-responsive genes, such as CBFs, COR, and LEA. Critical knowledge gaps remain, particularly in understanding ABA’s context-specific interactions with other hormones and the integration of calcium signaling with ABA pathways under cold stress. By synthesizing current research, this review enhances our understanding of tomato’s cold stress response and provides insights for genetically improving cold tolerance, supporting sustainable tomato production amid climate challenges.

Tomato (Solanum lycopersicum) is highly susceptible to both high and low temperatures, which threaten its growth, yield, and quality. Ascorbate peroxidase (APX) plays a pivotal role in plant responses to abiotic stresses. In this study, we unveil the positive involvement of heat- and cold-induced SlAPX2 in bolstering tomato resilience to temperature extremes. Knockout of SlAPX2 using the CRISPR/Cas9 technique exacerbated oxidative stress under heat and cold conditions, as evidenced by reduced Fv/Fm and increased electrolyte leakage (REL), malondialdehyde (MDA) content, and hydrogen peroxide (H₂O₂) levels. Furthermore, SlAPX2 expression was modulated by abscisic acid (ABA), and the transcription factor ABF4 in the ABA signaling pathway positively regulated SlAPX2 transcription. Using yeast one-hybrid (Y1H) and dual luciferase (LUC) assays, we found that ABF4 directly bound to the SlAPX2 promoter, thereby activating its transcription. Additionally, silencing of SlABF4 compromised tomato’s tolerance to heat or cold. Collectively, these findings reveal a regulatory module, SlABF4–SlAPX2, that enhances tomato tolerance to temperature extremes by detoxifying excessive reactive oxygen species (ROS). This study advances our understanding of ABA-mediated stress responses and highlights the SlABF4–SlAPX2 module as a promising target for breeding temperature-resilient tomato cultivars.

Biogenic volatile organic compounds (BVOCs) significantly impact air quality and climate. Mechanical injury is a common stressor affecting plants in both natural and urban environments, and it has potentially large influences on BVOC emissions. However, the interspecific variability in wounding-induced BVOC emissions remains poorly understood, particularly for subtropical trees and shrubs. In this study, we investigated the effects of controlled mechanical injury on isoprenoid and aromatic compound emissions in a taxonomically diverse set of 45 subtropical broad-leaved woody species, 26 species without and in 19 species with BVOC storage structures (oil glands, resin ducts and glandular trichomes for volatile compound storage). Emissions of light-weight non-stored isoprene and monoterpenes and aromatic compounds in non-storage species showed moderate and variable emission increases after mechanical injury, likely reflecting the wounding impacts on leaf physiology. In storage species, mechanical injury triggered a substantial release of monoterpenes and aromatic compounds due to the rupture of storage structures. Across species, the proportion of monoterpenes in total emissions increased from 40.9% to 85.4% after mechanical injury, with 32.2% of this increase attributed to newly released compounds not detected in emissions from intact leaves. Sesquiterpene emissions, in contrast, were generally low and decreased after mechanical injury. Furthermore, wounding responses varied among plant functional groups, with evergreen species and those adapted to high temperatures and shade exhibiting stronger damage-induced BVOC emissions than deciduous species and those adapted to dry or cold environments. These findings suggest that mechanical disturbances such as pruning can significantly enhance BVOC emissions in subtropical urban forests and should be considered when modeling BVOC fluxes in both natural and managed ecosystems. Further research is needed to elucidate the relationship between storage structure characteristics and BVOC emissions, as well as their broader ecological and atmospheric implications.

Flavonoids are essential secondary metabolites in plants, predominantly found in flowers, leaves, and fruits. They mainly include anthocyanins, proanthocyanidins, and flavonols. Transcription factors are a crucial family of proteins in plants, playing a significant role in regulating the biosynthesis of secondary metabolites. This review introduces flavonoids and explores the characteristics and biological functions of MYB transcription factors. It establishes a phylogenetic tree using Arabidopsis thaliana MYB transcription factors as an example, which includes 17 subgroups (S1–S17). The subgroups related to flavonoids are primarily concentrated in S17, further classified into A, C, D, E, and F. The review also discusses the different regulatory roles of MYB transcription factors in flavonoid synthesis in monocotyledonous and dicotyledonous plants. This knowledge provides a theoretical foundation for further studies on the diverse regulatory functions of MYB transcription factors in flavonoid biosynthesis across the plant kingdom.

Biogenic volatile organic compound (BVOC) emissions are pivotal in plant–environment interactions, yet their intrinsic linkages with photosynthesis and leaf economics across diverse tree species remain poorly integrated. This study investigated seven subtropical broadleaf species spanning distinct lineages to unravel how BVOC chemotypes (isoprene- vs. monoterpene-dominance) align with photosynthetic energy use and leaf structural traits. Using controlled measurements on excised branches to isolate physiological relationships, we combined TD-GC-MS, gas-exchange, and leaf trait analyses. The results revealed strong divergence in BVOC chemotypes that was broadly coherent with species phylogeny and ecological strategy. Isoprene-dominant (ISO) species exhibited higher photosynthetic rates (A), greater electron transport capacity (J_max), and elevated J_max/V_cmax ratios, consistent with the hypothesis that isoprene synthesis functions as a photosynthetic overflow mechanism for energy dissipation. In contrast, monoterpene-dominant (MTS) species displayed higher specific leaf weight (SLW) and relied on stored and induced emissions, reflecting a conservative, defense-oriented strategy. BVOC profiles were strongly correlated with SLW and photosynthetic capacity, highlighting a coordinated 'structure–function–volatile' adaptive syndrome. These findings suggest that BVOC emissions may be embedded within leaf economic strategies and photosynthetic networks, providing a basis to help refine next-generation BVOC models by integrating leaf structural traits (e.g., SLW) and photosynthetic electron transport capacity (J_max) into model parameterization.