Recent studies have witnessed that chemical modification can improve the physicochemical and functional properties of plants' polysaccharides. Herein, we modified the natural Lycium barbarum seed dreg polysaccharides (LBSDPs) by sulfation (S-LBSDPs), phosphorylation (P-LBSDPs), and carboxymethylation (C-LBSDPs), and evaluated the chemical composition and antioxidant activity of their derivatives. Natural polysaccharides and their derivatives exhibited typical polysaccharide absorption peaks and characteristic group absorption peaks in FT-IR spectra along with maximum UV absorption. After modification, the total sugar and protein contents of the derivatives were decreased, whereas the uronic acid content was increased. Among the three derivatives, sulfated polysaccharides displayed excellent thermal stability. S-LBSDP and P-LBSDP showed the highest ABTS radical scavenging and reducing power while S-LBSDPs and C-LBSDPs showed better DPPH radical scavenging effect, and P-LBSDPs showed considerable Fe²⁺ chelating ability. Our data indicate that chemical modifications can impart a positive effect on the antioxidant potential of plant-derived polysaccharides.

Programmed cell death (PCD) in tapetum provides nutrients for pollen development. Once this process becomes abnormal, the pollen will be aborted, and sterile lines will be formed. Lycium barbarum L. is a well-known medicinal and edible plant, and male sterile lines play an important role in the cultivation of its new varieties by utilizing hybrid vigor. However, the male sterility mechanism of L. barbarum is poorly understood. In this study, the main characteristic changes during the pollen development of L. barbarum sterile line (Ningqi No. 5) and fertile line (Ningqi No. 1) were compared through anatomical observation, physiological detection and gene expression analysis. Anatomical observation showed that compared with that of the fertile line, the tapetum of the sterile line persisted during pollen development, the organelle morphology and number of tapetal cells changed remarkably, and the PCD was remarkably delayed. Membranous peroxidation caused by reactive oxygen species (ROS) in the sterile line occurred from the late tetrad to the pollen grain stage, and that in Ningqi No. 1 transpired in the tetrad stage. This difference in the dynamic changes of ROS affected the redox balance of microspore development. qPCR detection of DYT1 and MS1 genes regulating tapetum development showed that compared with those in the fertile line, the expression levels of both genes in the sterile line changed significantly from pollen mother cell stage to pollen grain stage. This finding may be associated with the start-up delay of tapetal PCD. All these results suggested that abnormal tapetal PCD is an important mechanism leading to male sterility in L. barbarum.

Pollen fertility is a critical factor in seed development and crop breeding. Extensive studies have explored the mechanisms of pollen fertility in model plants and economic crops. However, the mechanisms of pollen abortion in medicinal and edible plants, including Lycium barbarum, remain elusive. This study utilized transcriptome analysis to identify key genes and regulatory networks implicated in pollen fertility in L. barbarum. The results demonstrated differential expression of 12,185 genes (DEGs) between the sterile and fertile lines, encompassing 489 genes that exhibited variation across the five stages of pollen development. Additionally, GO and KEGG enrichment analyses indicated that the DEGs were predominantly associated with energy metabolism, carbohydrate metabolism, and notably, hydrolase activity. Co-expression network analysis unveiled two modules intimately associated with fertility, each comprising 908 and 756 hub genes, incorporating β-1,3-glucanase genes (Glu) and co-expressed transcription factors (TFs). Phylogenetic analysis implied that LbGlu1 was a potential candidate gene implicated in regulating pollen abortion in L. barbarum. This work advances a novel understanding of pollen abortion in L. barbarum and offers theoretical support for the utilization of sterility genes to enhance crop improvement.

The recognition of pollen and pistil in the self-incompatibility process is generally determined by the interaction between the pollen S gene and pistil S gene located at the S locus. However, the regulatory mechanism of self-incompatibility in goji remains unknown. In this study, we used the self-compatible strain ‘13–19’ and self-incompatible strain ‘xin9’ from Ningxia as parents to create an F1 hybrid population. Reciprocal cross-pollination was performed within the same plant to evaluate the self-compatibility of the parents and F1 progeny. The parents and progeny were subjected to whole-genome resequencing, and mixed pools of DNA were constructed using 30 self-compatible and 30 self-incompatible individuals. Association analysis using the SNP-index method and Euclidean distance was employed to identify the key candidate region of the S locus. The candidate region was further annotated using the Swiss-Prot database to identify genes within the region. Additionally, transcriptome sequencing data from different organs/tissues, as well as from pistils of self-compatible and self-incompatible strains at control (0 h), short (0.5 h), medium (8 h), and long (48 h) time points after self-pollination and cross-pollination, were analyzed to assess differential gene expression and screen for self-compatibility-related loci. Specific primers were designed for PCR amplification to determine the S-RNase genotypes of the extreme parents. The results revealed that the S locus in goji is located within a 32.2 Mb region on chromosome 2 that contains a total of 108 annotated genes. Differential expression analysis showed that ten genes, including Lba02g01064, were specifically expressed in stamens, with four of them annotated as F-box genes, potentially serving as determinants of self-compatibility in stamens. Lba02g01102 was exclusively expressed in pistils and annotated as an S-RNase gene, likely involved in self-compatibility. The expression of Lba02g01102 in pistils decreased after self-pollination and cross-pollination. Six candidate genes exhibited significant changes after self-pollination and cross-pollination. Both parents and progeny carried two S-RNase alleles, and the S-RNase genotypes showed a significant correlation with self-compatibility, with the self-compatible progeny containing the S8-RNase allele. The identification of the S locus in goji provides molecular markers for future marker-assisted breeding and offers genetic resources for studying the mechanism of self-incompatibility in goji, thus contributing to the improvement of goji varieties.

Self-incompatibility is a widespread genetic mechanism found in flowering plants. It plays a crucial role in preventing inbreeding and promoting outcrossing. The genes that control self-incompatibility in plants are typically determined by the S-locus female determinant factor and the S-locus male determinant factor. In the Solanaceae family, the male determinant factor is often the SLF gene. In this research, we cloned and analyzed 13 S₂-LbSLF genes from the L. barbarum genome, which are located on chromosome 2 and close to the physical location of the S-locus female determinant factor S-RNase, covering a region of approximately 90.4 Mb. The amino acid sequence identity of the 13 S₂-LbSLFs is 58.46%, and they all possess relatively conserved motifs and typical F-box domains, without introns. A co-linearity analysis revealed that there are no tandemly repeated genes in the S₂-LbSLF genes, and that there are two pairs of co-linear genes between S₂-LbSLF and the tomato, which also belongs to the Solanaceae family. A phylogenetic analysis indicates that the S₂-LbSLF members can be divided into six groups, and it was found that the 13 S₂-LbSLFs are clustered with the SLF genes of tobacco and Petunia inflata to varying degrees, potentially serving as pollen determinant factors regulating self-incompatibility in L. barbarum. The results for the gene expression patterns suggest that S₂-LbSLF is only expressed in pollen tissue. The results of the yeast two-hybrid assay showed that the C-terminal region of S₂-LbSLFs lacking the F-box domain can interact with S-RNase. This study provides theoretical data for further investigation into the functions of S₂-LbSLF members, particularly for the identification of pollen determinant factors regulating self-incompatibility in L. barbarum.

Abscisic acid (ABA), a pivotal phytohormone regulating plant growth and stress adaptation, orchestrates abiotic stress responses through the ABA-responsive element-binding factors ABF/AREB/ABI5. Nevertheless, the functional characterization of ABF/AREB/ABI5 homologs in Z. jujuba cv. Dongzao remains unexplored. In this study, we identified seven ZjABF genes distributed across five chromosomes. Domain analyses revealed high structural conservation, particularly within the basic leucine zipper (bZIP) DNA-binding domain. Subcellular localization confirmed nuclear targeting of all seven ZjABF proteins. Phylogenetic classification resolved these factors into three clades (A–C). Cis-regulatory element profiling implicated the involvement of the ZjABFs in hormone signaling, abiotic stress transduction, and photoregulatory pathways. Synteny analyses identified three segmental duplication events within the gene family. Tissue-specific expression patterns indicated critical roles for ZjABF2 and ZjABF3 in fruit maturation, and most of the ABF/AREB/ABI5 genes were highly expressed in the root. Under drought stress, four ZjABF genes exhibited differential expression, with ZjABF2 demonstrating pronounced sensitivity. These findings establish a molecular framework for understanding ZjABF-mediated abiotic stress responses in non-model woody perennials.