The regulation of downstream responsive genes by transcription factors (TFs) is a critical step in the stress response system of plants. While bZIP transcription factors are known to play important roles in stress reactions, their functional characterization in soybeans remains limited. Here, we identified a soybean bZIP gene, GmbZIP60, which encodes a protein containing a typical bZIP domain with a basic region and a leucine zipper region. Subcellular localization studies confirmed that GmbZIP60 is localized in the nucleus. Expression analysis demonstrated that GmbZIP60 is induced by salt stress, drought stress, and various plant hormone treatments, including abscisic acid (ABA), ethylene (ETH), and methyl jasmonate acid (MeJA). Overexpressing GmbZIP60 (OE-GmbZIP60) in transgenic soybean and rice enhanced tolerance to both salt and drought stresses. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis indicated that the expression levels of abiotic stress-responsive genes were significantly higher in transgenic plants than in wild-type (WT) plants under stress conditions. Chromatin immunoprecipitation-qPCR (ChIP-qPCR) analysis further confirmed that GmbZIP60 directly binds to the promoters of abiotic stress-related genes induced by ABA, ETH, JA, and salicylic acid (SA). Overall, these findings revealed GmbZIP60 as a positive regulator of salt and drought stress tolerance.

The OsTHION family represents a class of cysteine-rich signal peptides widely recognized for their significant roles in plant disease resistance and immunity. While members of this family are known to be induced under various biotic and abiotic stresses, their responses to environmental stressors beyond disease resistance remain underexplored. This study investigates the evolution, expression patterns, and functional roles of the OsTHION gene family in rice (Oryza sativa) under diverse stress conditions. Using sequence data from the Phytozome database, we identified 44 OsTHION family members and classified them into four groups based on phylogenetic analysis. Cis-acting element analysis revealed that the promoter regions of OsTHION genes are enriched with regulatory elements associated with light response, hormone signaling, plant growth, and stress responses. The OsTHION genes exhibit complex organ-specific expression patterns, with OsTHION30 and OsTHION36 showing ubiquitous expression, while other members are highly expressed in specific tissues or developmental stages. Under drought, salt, and low-temperature stress, OsTHION genes undergo significant expression changes, underscoring their critical role in plant adaptation to environmental challenges. Notably, OsTHION15 was markedly upregulated under drought stress, and the Osthion15 mutant displayed heightened sensitivity to drought and ABA stress, confirming its pivotal role in stress resistance. RNA sequencing analysis identified many differentially expressed genes (DEGs), primarily enriched in pathways related to ribosomal function and plant hormone signaling, suggesting that OsTHION15 may regulate stress responses through multiple mechanisms. In summary, this study advances our understanding of the OsTHION gene family and highlights its intricate involvement in regulating rice growth, development, and environmental stress responses. These findings offer valuable insights and technical support for crop improvement, with potential applications in enhancing environmental adaptability and yield stability in crops.

Soybean (Glycine max) is a vital oilseed and economic crop in China, often constrained by drought, salinity, and biotic stresses. In this study, we identified a soybean bZIP transcription factor, GmbZIP59, whose expression is upregulated by salt, drought, ethylene (ETH), methyl jasmonate (MeJA), and abscisic acid (ABA). Overexpression of GmbZIP59 in Arabidopsis (OE-13 and OE-20, two independent Arabidopsis transgenic lines) exhibited enhanced resistance to Sclerotinia sclerotiorum (S. sclerotiorum), improved tolerance to salt stress, and increased sensitivity to phytohormones. Overexpression of GmbZIP59 in rice (OE-1 and OE-2, two independent rice transgenic lines) improved tolerance to salt and drought stresses. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis revealed that elevated expression of stress-related genes occurred in transgenic lines under adverse conditions. Furthermore, chromatin immunoprecipitation-qPCR (ChIP-qPCR) assays confirmed that GmbZIP59 directly binds to the promoters of ETH, MeJA, and ABA, responsive genes associated with stress responses. These findings demonstrate that GmbZIP59 acts as a positive regulator of biotic and abiotic stress tolerance in soybean.

Self-incompatibility (SI) is an important plant mechanism that prevents inbreeding depression by recognizing and rejecting self-pollen, thereby promoting outcrossing. However, SI can also act as a barrier in breeding programs, presenting significant challenges to breeders. Passion fruit (Passiflora edulis), a tropical fruit species of substantial economic importance, also serves as a valuable system for investigating SI mechanisms within the Passifloraceae. Nevertheless, the molecular basis of SI in passion fruit has not yet been elucidated. In this study, we investigated the SI system in yellow passion fruit (P. edulis f. flavicarpa) and employed transcriptomic analysis to examine the time-course transcriptional responses following different pollination treatments. Transcriptomic analysis revealed distinct gene expression dynamics under different pollination treatments: self-pollinated samples exhibited stronger and earlier transcriptional changes, whereas the number of differentially expressed genes (DEGs) in cross-pollinated samples was relatively lower. Numerous pathways previously associated with sporophytic self-incompatibility (SSI) were enriched in the stigma samples after self-pollination. Reactive oxygen species (ROS) are crucial signaling molecules involved in pollen germination and pollen tube growth during SI responses. Our results showed that ROS-related pathways were enriched in stigma tissues after self-pollination. In addition, oxidative stress-related responses were detected in the style shortly after self-pollination, suggesting that plastid-associated or general oxidative stress processes may also be involved, although the precise source of ROS requires further validation. FERONIA, ROP9, and ARC1 are key genes related to the SI system in Brassica. In the passion fruit SI response, the expression levels of these genes increased in the style, indicating a spatial expression pattern different from that reported in classical Brassicaceae SSI systems. Together with cytological observations showing that self-pollen rejection occurs at the stigma surface, our results suggest that yellow passion fruit may employ an SSI-like regulatory framework while exhibiting a lineage-specific spatial deployment of SI-related regulators. Overall, this study provides new transcriptomic insights into the SI mechanism of yellow passion fruit, establishes a molecular framework for understanding SI in P. edulis f. flavicarpa, and offers novel insights into the diversity of plant SI systems.

The ubiquitin–proteasome system (UPS) is a highly conserved protein degradation pathway in eukaryotic cells. Through precisely controlled proteolysis of key regulatory proteins, the UPS plays a particularly critical role in plant sexual reproduction, where precise spatiotemporal regulation is essential. The UPS governs multiple aspects of plant sexual reproduction, including male and female gametophyte development, pollen–pistil interactions, double fertilization, and post-fertilization embryogenesis and endosperm development. Among UPS components, E3 ubiquitin ligases play a central role by mediating the spatiotemporal degradation of key proteins, while E2 conjugating enzymes and deubiquitinating enzymes also make essential contributions. Through cross-species and cross-stage comparisons, we find that the UPS exhibits conserved regulatory logic—including cell-cycle gating, spatial control of protein accumulation, and signal integration—while also having evolved lineage-specific functional diversification. In this review, we systematically synthesize UPS functions across the reproductive cycle and highlight persistent knowledge gaps, aiming to provide an integrated framework and a reference for future studies investigating the regulatory roles of the UPS in plant sexual reproduction.