The yellow-to-green mutation in plant leaf color can be easily identified and used as a marker trait for seed purity identification, improved variety breeding, hybrid purity identification, and hybrid production. In this study, the leaves of yellow-to-green mutant ytg-1 of snap bean were selected as the experimental material, and the physiological mechanism underlying the leaf color change was studied. The mechanism was observed to belong to the lack of recovery type in the total chlorophyll stage. The decrease in chlorophyll content was due to the inhibition of the synthesis of Proto IX to Mg Proto IX. Genetic analysis revealed that a single recessive gene, pvytg-1, controlled the mutation trait. The gene was located in the 80-kb region of chromosome 10. Overall, six genes were observed within this interval, and based on gene functional annotation, Phvul.010G041700 was identified as the candidate gene. Sequencing and identification of Phvul.010G041700 revealed a single base insertion in ytg-1 compared with the wild-type, resulting in premature termination of the gene. The results of this study will facilitate the breeding and genetic improvement of snap bean in the future.

This study aimed to investigate the effects of arbuscular mycorrhizal fungi (AMF) on the growth and development of common bean (Phaseolus vulgaris L.) and on the microbial environment of the rhizosphere soil. Using the common bean inbred line ‘Jinguan’ as the experimental material, we examined the effects of AMF inoculation on seedling growth and the dynamic changes in rhizosphere microbial communities. The results showed that AMF could establish a stable symbiotic association with common bean roots. By applying seed coating technology to encapsulate AMF around the seeds, and in comparison with the blank control group (CK), the AMF-inoculated plants exhibited altered ratios of fungal to bacterial community structures in the rhizosphere soil. This alteration in root-associated communities subsequently modified plant growth performance, providing a reference for screening beneficial microbial consortia in common bean cultivation.

Cucumber (Cucumis sativus L.) is an economically important vegetable crop worldwide, but its yield and quality improvement are often constrained by drought stress. To investigate the physiological and molecular mechanisms by which exogenous allantoin enhances drought tolerance in cucumber, cucumber seedlings were sprayed with 6 mM allantoin solution once (A1), three times (A3), or five times (A5), while control plants were sprayed with distilled water (CK1, CK3, CK5). Each treatment consisted of three biological replicates. After treatment, drought stress was simulated by irrigating with 20% polyethylene glycol 6000 (PEG-6000) solution. The results showed that the protective effect of exogenous allantoin against drought stress was cumulative. After five applications (A5), the net photosynthetic rate (Pn) and water-use efficiency (WUE) of the plants were significantly higher than those of the corresponding control (CK5) (p < 0.01). The detached leaf water loss rate progressively decreased with an increasing number of allantoin applications, while the total leaf wax content increased approximately 2-fold (p < 0.01). Measurements of wax content in different plant tissues indicated that allantoin mainly induced wax accumulation in aboveground organs (leaf, stem, and fruit epidermis), and this effect was validated in three commercial varieties. Integrated transcriptomic and metabolomic analyses revealed that the cucumber CsCER1 gene (encoding a very-long-chain aldehyde decarbonylase) is a core allantoin-responsive gene. After silencing CsCER1 using virus-induced gene silencing (VIGS), the allantoin-induced wax accumulation and drought tolerance were almost completely lost: the wilting severity and detached leaf water loss rate of the silenced plants were comparable to those of the empty vector control, and no significant increase in wax content was observed. This study reveals a novel mechanism by which exogenous allantoin enhances drought tolerance in cucumber through activating CsCER1-mediated cuticular wax synthesis, providing a theoretical basis for the chemical regulation of drought tolerance in cucurbit crops.

Pod color is an essential economic trait of snap bean (Phaseolus vulgaris L.), and golden-yellow pods are more commercially popular than light-yellow varieties. Exploring the molecular regulatory mechanism underlying deep-yellow pod formation is essential for snap bean quality improvement. In this study, the wild-type cultivar Jinguan and the EMS-derived deep-yellow pod mutant pcm were used as materials. Integrative analyses of photosynthetic pigment quantification, genetic analysis, transcriptome sequencing, and targeted carotenoid metabolomics were performed to identify key genes and metabolic pathways governing pod color variation. Genetic analysis revealed that the deep-yellow pod trait of the pcm is stably inherited and controlled by a nuclear recessive gene. Transcriptome screening identified three differentially expressed key genes, PSY (Phvul.006G024100g), CCD4 (Phvul.002G120600g), and CYP707A (Phvul.002G122200g), whose expression patterns were strongly correlated with carotenoid accumulation. Metabolomic results demonstrated that the pcm presented reduced upstream β-carotene content, while the synthesis and accumulation of downstream chromogenic carotenoids, including zeaxanthin and capsorubin, were significantly enhanced, resulting in elevated total carotenoid content. Collectively, the differential expression of these genes remodels carotenoid metabolism and ultimately contributes to the deep-yellow pod phenotype. This study explores the regulatory mechanism of carotenoid metabolism in pod color formation, providing valuable theoretical support and genetic resources for quality breeding of snap beans.