TY  - EJOU
AU  - Chen, Xinxin 
AU  - Li, Fuxin 
AU  - Jia, Jingyu 
AU  - Tian, Yajing 
AU  - Li, Xin 

TI  - HuLBD1 Promotes Flavonoid Biosynthesis Involved in Senescence of <i>Hylocereus undatus</i> by Negatively Regulating <i>HuCHS</i>
T2  - Phyton-International Journal of Experimental Botany

PY  - 2025
VL  - 94
IS  - 3
SN  - 1851-5657

AB  - In plants, transcription factor (TF) family LATERAL ORGAN BOUNDARIES DOMAIN (LBD) has been identified to be involved in the ripening and senescence processes of fruits. However, the function of LBD in <i>Hylocereus undatus</i> (Haw.) Britton & Rose (<i>H. undatus</i>) has not been reported yet. Through transcriptomic analysis, virus-induced gene silencing (VIGS) technology, and RT-qPCR validation, we investigated the role of the LBD TFs in the senescence of <i>H. undatus</i>. Transcriptomic analysis revealed that HuLBD1 is a key transcription factor of the LBD family regulating <i>H. undatus</i> senescence. After silencing <i>HuLBD1</i>, 5075 differentially expressed genes (DEGs) were identified. GSEA results showed that these DEGs were mainly enriched in the phenylpropanoids and flavonoid biosynthesis pathway. The leading subset of genes in these two pathways included 16 DEGs, with four upregulated genes, <i>HuCHS1-2</i>, <i>HuFLS1</i>, <i>HuCYP75B2</i>, and <i>HuCHS5-2</i> being central in the Protein-Protein Interaction (PPI) network. <i>H. undatus</i> phenotypic experiments confirmed that silencing <i>HuLBD1</i> significantly increased the flavonoid content in the fruit peel, and RT-qPCR validation showed that the gene expression trends were consistent with the RNA-seq data. The study indicated that HuLBD1 likely delays the fruit senescence process by negatively regulating the expression of four key genes, including <i>HuCHS1-2</i>, thus promoting the synthesis of phenylpropanoids such as flavonoids. In conclusion, our findings suggest that the HuLBD1 TF plays an important role in the senescence of <i>H. undatus</i> fruit, providing a theoretical basis for postharvest senescence control.
KW  - HuLBD1; <i>Hylocereus undatus</i>; flavonoid biosynthesis; VIGS; transcriptomics

DO  - 10.32604/phyton.2025.062015