Saline–alkali environments restrict soybean production in China. Wild soybean genes can be used to improve the alkaline tolerance of cultivated soybean in molecular breeding. The expansin protein family promotes cell wall expansion. In this study, the relative expression levels of expansin family genes in wild soybean treated with 50 mM NaHCO₃ were measured at 0, 3, 6, and 12 h, and the relative expression of GsEXPA8 was found to be higher at 12 h. Wild soybean was treated with abscisic acid (ABA), indole-3-acetic acid (IAA), gibberellic acid (GA), and jasmonic acid (JA), and GsEXPA8 was found to respond to ABA and IAA signals. Sequence analysis shows that GsEXPA8 has DPBB_EXPA and expansin domains. Subcellular localization analysis shows that GsEXPA8 was localized in the cytoplasm in protoplasts and the cell membrane or wall in tobacco, indicating that it has nuclear membrane localization signals. GsEXPA8 overexpression reduced the malondialdehyde content in transgenic plants treated with NaHCO₃ and increased peroxidase activity before treatment. After the transformation of soybean roots from hair roots, GsEXPA8 was found to be expressed in the outer root cells and promote the development of thicker, shorter roots, thereby improving the plant’s alkaline tolerance. Stable GsEXPA8 transformation improved saline alkaline tolerance via the regulation of the alkali stress-related genes GmKIN1, GmRD22, GmDnaJA6, GmNFYC1, and GmMYB14. These findings provide support for further research on alkali-tolerance regulation pathways and molecular breeding for alkali tolerance.

Soil alkalinity severely restricts the cultivation of Lupinus angustifolius, a valuable legume. Wild soybean (Glycine soja) is a leguminous plant with extremely strong alkaline resistance (pH 8.5). Transferring the alkali-tolerant genes from wild soybeans into lupinus can effectively enhance the alkali tolerance. In this study, we combined transcriptome profiling and genetic transformation to elucidate the molecular basis of alkaline stress response in lupinus. RNA-seq analysis of root tips under acid (HCl, pH 4.0) and alkali (NaHCO₃, pH 8.5) stress revealed 104,353 annotated unigenes, with differential expression patterns highlighting enrichment in cellular component, binding, and catalytic activity categories. KEGG pathway analysis indicated that early responses involved ribosome-related pathways, while later stages activated plant hormone signaling and MAPK pathways. Notably, no homeodomain-leucine zipper (HD-Zip) family genes were identified in the lupinus genome. Therefore, we transferred GsHZ4, an alkali-resistant HD-Zip transcription factor from wild soybean into lupinus hairy roots via Agrobacterium rhizogenes-mediated transformation. Overexpression of GsHZ4 significantly enhanced antioxidant enzyme activities (CAT, POD, and SOD) and reduced malondialdehyde content under NaHCO₃ stress. Furthermore, the promoter of GsHZ4 expression was strongly induced by indole-3-acetic acid (IAA). Key alkali-responsive genes (LaKIN, LaMYB34, LaDnaJ1, LaDnaJ20, LaNAC22, and LaNAC35) were upregulated in transgenic lines, suggesting that GsHZ4 integrates into the endogenous stress-regulation network. Our findings demonstrate that heterologous expression of GsHZ4 can enhance alkaline tolerance of lupinus, providing a novel strategy for breeding stress-resistant varieties and expanding lupinus cultivation in saline–alkali soils.

Tomato (Solanum lycopersicum L.) is a globally important vegetable crop and a key model species for studying reproductive development in other Solanaceae members with edible fleshy fruits, such as eggplant, sweet and hot peppers, and Physalis spp. The morphogenesis and patterning of tomato floral organs fundamentally determine fruit yield and quality. Recent advances in high-throughput sequencing and gene editing have significantly deepened our understanding of the molecular network regulating tomato reproductive development. This process, from the transition of vegetative shoot apical meristem to the inflorescence meristem, forming floral meristems with primordia of sepals, petals, stamens, carpels, and fruits, is precisely coordinated by a genetic network involving homeobox and other types of transcription factors, along with signaling pathways. This review systematically outlines the core regulatory network, with an emphasis on the MADS-domain transcription factor family and its associated ABCDE model. Integrating insights from hormone signaling and mutant phenotypes, we summarize the maintenance of inflorescence meristem identity, the specification of floral meristems, and the morphogenetic patterns and core gene regulatory mechanisms for each floral whorl in tomato. We further extend this framework to the flower–fruit continuum, examining how carpel development, floral meristem termination, and ovule differentiation influence fruit morphology, locule number, pericarp structure, and metabolic traits. Finally, we discuss the integration of floral organ development with molecular design breeding and formulate a forward-looking research agenda that translates floral regulatory mechanisms to breeding strategies for yield, uniformity, and fruit quality. This synthesis provides a theoretical foundation and genetic resources for the genetic improvement of tomato flower architecture and its underlying regulatory mechanisms.