Dirigent proteins (DIR) play important roles in the biosynthesis of lignins and lignans, defensive responses, secondary metabolism, and disease resistance in plants. The DIR gene family has been identified and studied in many plants. However, the identification of DIR gene family in eggplant has not been conducted yet. Therefore, in this study, based on the available genome information of eggplant, the DIR family genes in eggplant were identified with bioinformatics methods. The expression pattern analyses of eggplant DIR family genes in different organs and stresses were also conducted to understand their biological functions. The results showed that a total of 24 DIR genes were identified in the eggplant, which were divided into three subfamilies (DIR-a, DIR-b/d, and DIR-e). Synteny analysis of DIR genes among eggplant, Arabidopsis, and rice showed that 15 eggplant DIR genes were colinear with 18 Arabidopsis DIR genes, and 16 eggplant DIR genes were colinear with 15 rice DIR genes. Phylogenetic tree analysis showed that 19 pairs of orthologous genes were identified between eggplant and pepper. The cis-acting elements analysis implied that the eggplant DIR genes contained a lot of cis-elements associated with stress and hormone response. The organ-specific expression analysis of eggplant DIR family genes revealed that only the SmDIR3 gene was highly expressed in all the 19 organs of eggplant. Some SmDIR genes, including SmDIR7, SmDIR8, SmDIR11, SmDIR14, SmDIR18, SmDIR19, SmDIR20, and SmDIR23, were not or were lowly expressed in the eggplant organs, while the other eggplant DIR family genes showed an organ-specific expression pattern. Furthermore, 19 of 24 SmDIR genes were differentially expressed in response to abiotic and biotic stresses. 5 SmDIR genes, including SmDIR3, SmDIR5, SmDIR6, SmDIR12, and SmDIR22, were differentially expressed under multiple types of abiotic and biotic stresses. Especially notable, the SmDIR22 gene was differentially expressed under three types of abiotic stresses and two types of biotic stresses, which indicated that the SmDIR22 gene plays an important role in the response to abiotic and biotic stresses. These results provide valuable evidence for a better understanding of the biological role of DIR genes in eggplant.

Pigments in plants not only determine their visual characteristics but also play crucial roles in photosynthesis, pollinator attraction, and disease resistance. The diverse colors of chili peppers arise from various pigments. However, detailed reports on the genetic and metabolic changes of these pigments in the developmental stages of colorful chili peppers are limited. In this study, we analyzed the content of anthocyanins and carotenoids in the fruits of the cultivated pepper variety H18 at different growth and development stages. Our findings revealed that, as the fruits mature, the anthocyanin content gradually decreases while the carotenoid content increases. Using the transcriptomic and metabolomic sequencing of pepper fruits at various developmental stages, we identified four types of anthocyanins: pelargonidin, cyanidin, delphinidin, and peonidin, as well as a small amount of proanthocyanidins. The concentrations of these anthocyanins generally showed a decreasing trend, and the expression patterns of anthocyanin biosynthesis genes were consistent with the metabolic data. In the analysis of carotenoids, we found that, apart from Lutein, the concentrations of all other detected carotenoids increased during fruit development. Most carotenoids began to accumulate significantly at the orange fruit stage (H18-O) and peaked at the red fruit stage (H18-R). Transcriptomic and RT-qPCR data indicated that the expression of carotenoid biosynthesis genes also increased progressively. Furthermore, we investigated the degradation of anthocyanins and identified potential degradation genes, including BGLU, POD, and PPO. This study provides deep insights into the mechanisms underlying pigment changes in colorful peppers, which may contribute to the improvement of pepper varieties and future research on pigment regulatory mechanisms.

Aiming at the problem of inaccurate fruit recognition and fruit diameter detection in the persimmon inspection process, this research proposes a novel persimmon accurate recognition and fruit diameter detection algorithm based on the Region-based Convolutional Neural Network (RCNN) Mask and instance segmentation algorithm. The algorithm strategically targets the object of interest by integrating cropping, morphological processing, and concave point segmentation modules into the fully connected layer following the Region of Interest (RoI) feature. Initially, the algorithm separates the front and back background of the cropped target object using morphological processing to obtain a binarized image. Subsequently, concave point segmentation is applied to address sticking issues arising from overlapping or occlusion between fruits, while a template matching algorithm helps in image recognition. The improved instance segmentation algorithm enhances the segmentation accuracy of the target fruit and reduces the relative error in the fruit diameter measurement caused by sticking problems during occlusion and overlap. Notably, compared with the original algorithm, the improved Mask RCNN instance segmentation algorithm achieves a mean Average Precision (mAP) of 94.25%, representing an improvement of 8.05%, with the Mean Intersection-over-Union (MIoU) value increasing by 18.5%. The maximum relative error in fruit diameter measurement is reduced to 1.3%, while the maximum relative error in fruit thickness measurement is 1.98%, meeting the stringent requirements of orchard inspection. Overall, the proposed method enhances the precision and accuracy of fruit diameter detection, offering valuable theoretical and technical insights for intelligent inspection, yield estimation, fruit detection, and mechanized picking in the agricultural domain.

The growth-regulating factor ( GRF ) and GRF -interacting factor ( GIF ) gene families play crucial roles in enhancing plant genetic transformation efficiency. However, the functional contributions of pepper GRF and GIF genes in improving transformation efficiency remain unexplored. In this study, we identified 31 GRF genes and 9 GIF genes across pepper, tomato, and tobacco. A systematic analysis was conducted to characterize their phylogenetic relationships, gene structures, collinearity, and expression patterns. Collinearity analysis revealed large-scale duplication events among these three Solanaceae species. Furthermore, qRT-PCR analysis demonstrated significantly elevated ex-pression levels of pepper GRF and GIF genes in regenerative tissues, indicating their critical functional roles during pepper regeneration processes. Our findings provide novel insights into the evolution of GRF and GIF gene families in Solanaceous plants and identify several key candidate genes for future functional studies aimed at enhancing pepper regeneration efficiency and genetic transformation.

Golden2-like (GLK) genes positively regulate chloroplast development, increase crop yields, and improve fruit quality. However, there has been no comprehensive identification and characterization of GLKs in watermelon. In this study, a total of 48 ClGLKs were identified in the watermelon genome. Based on phylogenetic analysis, they were divided into five groups. ClGLKs within the same group showed a similar gene structure and conserved motif compositions. Promoter analysis indicated that cis-elements responsive to light were the most abundant, though cis-elements associated with hormones, stress, and developmental regulation were also identified in ClGLKs promoters. Expression analysis indicated significant responses of some ClGLKs to drought and CGMMV stress, suggesting that these genes may participate in responses to biotic and abiotic stresses. Phenotypic analyses revealed enhanced chloroplast development and increased thylakoid density and chlorophyll content in the pericarp of a “dark green” watermelon cultivar. ClGLK8 was identified as the homolog of GLK1-2, the genes that promote chloroplast development and chlorophyll biosynthesis in fruits, and showed significantly increased expression in accordance with chloroplast development and chlorophyll accumulation. Our results provide detailed knowledge of the ClGLKs, which will enhance efforts to further improve the fruit quality of watermelon.

Tomato fruit rot severely impacts yield and quality, causing economic losses. This study aimed to identify the pathogenic fungi associated with post-harvest tomato fruit rot and characterize the transcriptomic responses of tomatoes. Pathogens were isolated from diseased tomato fruit tissues and identified using morphology, phylogenetic analysis, and in vitro pathogenicity tests. The genome of Cladosporium oxysporum Co-1 was assembled and annotated. RNA-seq analysis was used to profile transcriptional changes in tomatoes infected with C. oxysporum Co-1, with RT-qPCR validating the RNA-seq data and spectrophotometric assays analyzing the host physiological responses. Three pathogenic fungi were isolated. Colonies of C. oxysporum exhibited a near-circular shape, with colonies transitioning from an olive-green center to gray-green at the edges, and based on ITS, β-tubulin, and EF-1α gene sequences, this isolate exhibited 99% identity with C. oxysporum. The other two fungal isolates were identified as Alternaria alternata and Fusarium incarnatum, respectively, based on morphological and multi-locus sequence analysis. All three strains induced fruit rot and browning in tomatoes, confirming their pathogenicity. The genome size of C. oxysporum Co-1 was 34,515,558 bp, comprising 52 scaffolds with a GC content of 52.82%, and encoding 10,081 protein-coding genes. RNA-seq analysis showed dynamic gene expression changes in tomatoes infected with strain A, with differentially expressed genes enriched in pathogenicity-related pathways. Spectrophotometric assays revealed that peroxidase and superoxide dismutase activities decreased initially followed by an increase post-inoculation with C. oxysporum, indicating that tomatoes defend against pathogen infection through the antioxidant enzyme system. These findings revealed the pathogenic fungi were associated with post-harvest tomato rot disease, provided genomic resources for C. oxysporum, and provided insight into the host’s response to this strain.