园艺研究(英文)最新文献

[This corrects the article DOI: 10.1093/hr/uhae367.].

The GOLDEN2-LIKE (GLK) gene family, known for its role in chloroplast development, has recently been implicated in involvement of anthocyanin biosynthesis in kiwifruit (Actinidia spp.), but the underlying regulatory mechanism remains unclear. Here we report the characterization of a kiwifruit GLK homolog AcGLK2 in regulating anthocyanin accumulation. We found that expression of AcGLK2 is much higher exclusively in the red pigment-accumulated fruit tissue. Overexpression of AcGLK2 in Arabidopsis and kiwifruit significantly enhanced anthocyanin content, whereas its RNAi-mediated silencing compromised anthocyanin accumulation. RNA-Seq analysis revealed significant upregulation of many structural genes and transcription factors (TFs) associated with the flavonoid pathway in AcGLK2-overexpressing kiwifruit. ChIP-Seq analysis indicated that AcGLK2 directly binds to AcMYB5 and AcTRY. We showed AcMYB5, an R2R3-MYB TF, promotes anthocyanin accumulation by interacting with the bHLH protein AcbHLH42, while AcTRY, an R3-MYB protein, competitively inhibits the interaction between key MYBs and AcbHLH42, thereby repressing anthocyanin biosynthesis. Transgenic and molecular assays in tobacco, tomato, and kiwifruit demonstrated that AcGLK2 positively participates into regulation of anthocyanin accumulation through transcriptionally activating AcMYB5 expression and concomitantly suppressing AcTRY expression. This study reveals the dual regulatory mechanism of AcGLK2 in anthocyanin biosynthesis, broadening the understanding of GLK gene functions and providing a valuable genetic resource for molecular breeding of nutritional quality in kiwifruit and other crops.

Chlorophyll, the pigment in plant leaves, is crucial for capturing light during photosynthesis. Mutations that disrupt chlorophyll production or chloroplast development frequently lead to changes in leaf color. Here, we report the identification and characterization of a chlorotic mutant in cucumber (Cucumis sativus L.), named tnyl3, which exhibits chlorotic cotyledons and seedling lethality. Map-based cloning revealed that the tnyl3 mutation results from a Tnt1 retrotransposon insertion in a gene encoding nuclear factor Y subunit B3 (NF-YB3), a transcription factor subunit. Compared with the wild type, the mutant exhibited dramatic decreases in chlorophyll a and b levels and a significantly lower net photosynthetic rate. Ultrastructural analysis revealed that the chloroplasts in the tnyl3 mutants are structurally abnormal and characterized by underdeveloped thylakoid membranes. Gene expression analyses revealed that CsNF-YB3 is highly expressed in young seedling tissues and is upregulated by light. CRISPR/Cas9 analyses subsequently confirmed that the tnyl3 phenotype is caused by the loss of CsNF-YB3. Yeast two-hybrid and split-LUC assays demonstrated that CsNF-YB3 interacts directly with the cucumber NF-YC2 protein and promotes CsTIC21 transcription, suggesting that it functions as part of an NF-Y transcriptional complex. Transcriptome profiling of the mutant revealed extensive downregulation of photosynthesis-related genes, which is consistent with its impaired chloroplast function. Our findings establish CsNF-YB3 as a crucial genetic factor for chloroplast development and pigment synthesis in cucumber. This work provides new insight into the NF-Y-mediated regulatory network controlling chloroplast biogenesis and offers a potential genetic target for improving plant photosynthetic performance and vigor.

Tomatoes are highly nutritious and represent one of the important vegetable fruits worldwide. Both historically and moving forward, genetic decoding and precision breeding remain fundamental to tomato improvement. Here, we summarize pivotal advances in decoding tomato genomes across domestication, improvement and evolution processes and provide a perspective on future breeding through precision design. In-depth population genetic studies have revealed how artificial selection systematically prioritized yield-related alleles at the cost of narrowing genetic diversity, especially at flavor-related loci-highlighting the urgent need to reconcile these trade-offs. Comparative genomics across species, viewed through an evolutionary lens, has uncovered critical insights into functional genes, deepening our understanding of the genetic architecture and regulatory mechanisms underlying key traits. Collectively, these advances have enabled precise identification and functional characterization of key genetic elements, paving the way for systematic redomestication of tomato through precision genomic design. Looking ahead, more efficient and precise breeding strategies will be required to accelerate genetic gains in tomato in the coming decades. The integration of recent genomic advances, coupled with genomic selection and artificial intelligence, into genomic design breeding offers a transformative framework, unlocking unprecedented opportunities for developing highly flavorful and consumer-customized tomato varieties.

The apical bud-break is an important stage in the regulation of lotus (Nelumbo nucifera Gaertn.) flowering. Phytohormones play a key role in the development of plant buds, but the molecular mechanisms underlying the crosstalk between different phytohormone signals, especially abscisic acid (ABA) and jasmonic acid (JA), in lotus bud-break remain unclear. In this study, we found that the exogenous application of ABA inhibited the lotus apical bud-break. In addition, the expression of the gene encoding ABSCISIC ACID INSENSITIVE 5 (NnABI5), a crucial regulator of ABA signaling, was gradually downregulated during lotus apical bud-break. The transient overexpression of NnABI5 in lotus and heterologous expression in Arabidopsis thaliana (L.) Heynh. demonstrated that NnABI5 negatively regulates apical bud-break and seed germination. NnABI5 interacted with the JA pathway inhibitors NnTIF[F/Y] XG 10A/B (NnTIFY10A/B), reducing the binding ability of NnABI5 to response genes EARLY METHIONINE-LABELED 1 (NnEM1) and NnEM6. In contrast, NnTIFY10A/B positively regulates apical bud break and seed germination. Notably, exogenous application of the JA biosynthesis inhibitor DIECA alleviated the inhibitory effect of ABA. In vitro protein degradation assays revealed that ABA could accelerate the degradation of NnTIFY10A/B. In summary, our data reveal the crosstalk of the JA and ABA signaling pathways in lotus apical bud-break, laying a theoretical foundation for understanding the regulation of flowering in this species.

Enzymatic browning significantly affects the processing and quality maintenance of a wide range of horticultural produce. Identifying key regulators of browning is essential for elucidating its underlying mechanisms and developing effective mitigation strategies. In this study, transcriptomic comparison between potato cultivars with contrasting browning sensitivities identified a small auxin-up RNA, StSAUR31, as a potential regulator of auxin-mediated browning inhibition in potato. Functional analyses showed that overexpression of StSAUR31 markedly reduced browning intensity and PPO activity, whereas knockout of StSAUR31 produced the opposite phenotype. Correspondingly, StuPPO1 protein abundance decreased in StSAUR31 overexpression lines and increased in knockout lines. Mechanistically, StSAUR31 physically interacted with StuPPO1 in an auxin-enhanced manner, partially altering its subcellular localization and reducing its accumulation in plastids. Additionally, StSAUR31 downregulated StuPPO1 expression, reduced endogenous free tyrosine levels, and enhanced antioxidant capacity. Collectively, these findings indicated that StSAUR31 coordinately regulated PPO activity, substrate availability, and antioxidant capacity, thereby integrating multiple mechanisms to suppress enzymatic browning in potatoes. These results advance our understanding of the crosstalk between auxin signaling and enzymatic browning, providing new insights into the role of hormone signaling in postharvest quality regulation.