Watermelon (Citrullus lanatus) and melon (Cucumis melo) are globally important cucurbit crops, with China being the largest producer and consumer. Traditional breeding methods face difficulties in significantly improving yield and quality. Smart breeding, which combines genomics, gene editing, and artificial intelligence (AI), holds great promise but fundamentally depends on understanding the molecular mechanisms controlling important agronomic traits. This review summarizes the progress made over recent decades in discovering and understanding the functions of genes that control essential traits in watermelon and melon, focusing on plant architecture, fruit quality, and disease resistance. However, major challenges remain: relatively few genes have been fully validated, the complex gene networks are not fully unraveled, and technical hurdles like low genetic transformation efficiency and difficulties in large-scale trait phenotyping limit progress. To overcome these and enable the development of superior new varieties, future research priorities should focus on the following: (1) systematic discovery of genes using comprehensive genome collections (pan-genomes) and multi-level data analysis (multi-omics); (2) deepening the study of gene functions and interactions using advanced gene editing and epigenetics; (3) faster integration of molecular knowledge into smart breeding systems; (4) solving the problems of genetic transformation and enabling efficient large-scale trait and genetic data collection (high-throughput phenotyping and genotyping).

Spines are an important trait of cucumber fruit that affects commercial quality, smoothness, transportation, storage, and pesticide residue retention. Spine Base Size1 (CsSBS1), a C2H2 zinc-finger transcription factor, has been identified as a determinant of cucumber fruit spine size, though its molecular mechanism remains unclear. Here, our study found that exogenous ethylene treatment partially restored the small spine base phenotype in the Cssbs1 near-isogenic line (NIL) S-SB and knockout lines, while the ethylene inhibitor aminoethoxyvinylglycine reduced spine base size in wild-type L-SB plants. Further investigation revealed that CsSBS1 directly bound to the promoter of the ethylene-biosynthesis gene 1-aminocyclopropane-1-carboxylate oxidase 2 (CsACO2) and activated its expression. Silencing CsACO2 through RNA interference inhibited fruit spine base expansion in wild-type plants, whereas enhanced CsACO2 expression resulted in larger spine bases in S-SB plants. Additionally, knockout of CsTTG1 led to smaller fruit spine bases and decreased ethylene release. Genetic and biochemical analyses indicated that CsTTG1 enhances CsSBS1-mediated transcriptional activation of CsACO2. Overall, our results reveal a CsSBS1-CsTTG1 regulatory module that regulates fruit spine base size via CsACO2-mediated ethylene biosynthesis in cucumber.

The early flowering and less lateral branches in watermelon hold significant agricultural value. The synergistic effects of these traits provide an ideal template for watermelon plant architecture improvement. However, the molecular regulatory networks underlying the development of lateral organs (including branches and flowers) in watermelon remain unclear. In this study, we found ClTFL1 knockout lines significantly promote flowering time and inhibit lateral branching and tendril formation, while also leading to a mild apical flower phenotype. These findings indicate that the function of ClTFL1 in watermelon is more extensive than that of its homologous genes in Arabidopsis, rice, and tomato. Through yeast two-hybrid screening, we identified the interacting proteins of ClTFL1, including members of the 14-3-3 family ClGRF8, ClGRF9, and ClGRF12. Bimolecular fluorescence complementation (BiFC) assays further demonstrated ClTFL1 could directly interact with the ClGRF8, ClGRF9, and ClGRF12 protein. The knockout of ClGRF8 and ClGRF12 leads to reduced lateral branches and early flowering. These phenotypes are highly consistent with those of ClTFL1 knockout mutants. Our findings demonstrate the important role of the ClTFL1-ClGRFs module in regulating lateral organ development and flowering time in watermelon, offering important targets for watermelon plant architectural modification and molecular breeding.

Frequent occurrences of pests and diseases in tomatoes severely restrict yield and quality improvements. Traditional detection methods are labor-intensive and prone to errors, while advancements in deep learning provide a promising solution for rapid and accurate identification. However, existing deep learning-based models often face high computational complexity and a large number of parameters, which hinder their deployment on resource-constrained edge devices. To overcome this limitation, we propose a novel lightweight detection model named YOLOv11n-KL based on the YOLOv11n framework. In this model, the feature extraction capability for small targets and the overall computational efficiency are enhanced through the integration of the Conv_KW and C3k2_KW modules, both of which incorporate the KernelWarehouse (KW) algorithm, and the Detect_LSCD detection head is employed to enable parameter sharing and adaptive multi-scale feature calibration. The results indicate that YOLOv11n-KL achieves superior performance in tomato pest and disease detection, balancing lightweight design and detection accuracy. The model achieves an mAP@0.5 of 92.5% with only 3.0 GFLOPs and 5.2 M parameters, reducing computational cost by 52.4% and improving mAP@0.5 by 0.9% over YOLOv11n. With its low complexity and high precision, YOLOv11n-KL is well-suited for resource-constrained applications. The proposed YOLOv11n-KL model offers an effective solution for detecting tomato pests and diseases, serving as a useful reference for agricultural automation.

Watermelon is an economically important horticultural crop cultivated worldwide. The ERF family is one of the largest transcription factor families in plan

Plant architecture is a critical agronomic trait in watermelon (Citrullus lanatus), with vine length directly influencing planting density, light interception, and field management efficiency. Short-vine forms have become important agronomic targets in breeding due to their advantages of high-density planting, efficient light utilization, and simplified field management. In this study, a dwarf mutant, designated PKH207, was identified from an ethyl methanesulfonate (EMS)-mutagenized population of the watermelon inbred line G42. The mutant exhibited significantly reduced plant height and shortened internodes due to decreased cell expansion in stem tissues. Genetic analysis indicated that the dwarf phenotype in PKH207 is controlled by a single recessive gene, which was named Cldw2 (Citrullus lanatus dwarf mutant 2). Using a population of 558 F₂ plants, bulked segregant analysis sequencing (BSA-seq) and linkage mapping delimited the causal locus to a 540.6 kb region on chromosome 10. Within this interval, a single-nucleotide polymorphism (SNP) mutation was identified in the gene ClG42_10g0100600, encoding an α-tubulin, and this gene was determined to be the candidate gene for the dwarf phenotype. Transcriptome analysis revealed that this mutation significantly disrupts key biological processes, including cell wall biosynthesis, microtubule cytoskeleton organization, and auxin signaling pathways, contributing to the dwarfism phenotype. This study identifies a novel dwarfing allele in cucurbits and provides a direct molecular target for breeding compact watermelon cultivars suited to high-density production.