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Journal of Integrative Agriculture  2026, Vol. 25 Issue (3): 977-988    DOI: 10.1016/j.jia.2025.02.043
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Genome-wide identification of the peach LOB/LBD genes and the positive role of the PpNAP4–PpLOB1 module in peach fruit softening

Jieyu Dai1, Ze Xu1, 2, Qianjin Zhan1, Jingwen Zhu1, Lijun Cao3, 4, Zhanling Lu1, Yuting Xu1, Tongyang Kang1, Yanan Hu1#, Caiping Zhao1

1 College of Horticulture, Northwest A&F University, Yangling 712100, China

2 Institute of Fruit Tree Research, Guangdong Academy of Agricultural Sciences/Key Laboratory of South Subtropical Fruit Biology and Genetic Resource Utilization, Ministry of Agriculture and Rural Affairs/Guangdong Provincial Key Laboratory of Tropical and Subtropical Fruit Tree Research, Guangzhou 510640, China

3 Howard Hughes Medical Institute, Duke University, Durham, NC 27708, USA

4 Department of Biology, Duke University, Durham, NC 27708, USA

 Highlights 
● PpLOB1 positively regulates peach softening.
● PpNAP4 activates PpLOB1 expression.

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摘要  

软化是肉质果实成熟阶段的必然过程,极大地影响着果实的品质和贮藏时间。桃是温带地区重要的经济果树之一;然而,桃果实软化速度快,贮藏时间短,由此在生产和运输上产生了较大损失。同时,对于桃果实软化的相关研究报道仍较少。LOB/LBD 蛋白是植物生长发育的重要调控因子,至今已有多个家族成员被报道参与调控果实的软化过程。本文中鉴定得到了42个桃LOB/LBD家族成员,表达分析显示PpLOB1在成熟桃果实中大量表达。进化分析表明PpLOB1属于Class II 亚家族,并且与多个软化相关LOB/LBD蛋白表现出高同源性。PpLOB1的瞬时表达试验说明其正向调控桃果实的软化,进一步的分子生物学试验显示其能靶向激活PpPL1和PpPL15的表达,从而调控果实的软化进程。此外,PpNAP4能作为PpLOB1的上游调控因子影响其表达,且与PpNAP6协同调控此过程。综上,本文揭示了PpNAP4和PpLOB1组成的模块共同调控桃果实软化的分子机制。



Abstract  

Softening of fleshy fruits during ripening and postharvest is a programmed physiological process that substantially impacts fruit quality and shelf life.  However, the molecular mechanism underlying peach softening remains largely unknown.  Lateral organ boundary (LOB) domain (LBD) proteins are pivotal regulators of plant growth and development.  To date, certain LOB/LBD transcription factors are seemingly implicated in fruit softening.  In this study, we identified 42 LOB/LBD genes in the peach genome.  Expression analysis showed a significant upregulation of PpLOB1 transcripts toward peach fruit ripening.  PpLOB1 was classified into Class II subgroup, and showed high sequence similarity to several softening-related LOB/LBD transcription factors.  Transient transformation assays showed that PpLOB1 positively modulates peach softening.  Further experiments demonstrated that PpLOB1 directly targets and activates the promoters of pectate lyase 1 (PpPL1) and PpPL15, thereby contributing to the regulation of fruit softening.  Additionally, PpNAP4 up-regulates PpLOB1 expression by binding to its promoter.  Meanwhile, our findings revealed that PpNAP4 and PpNAP6 cooperatively modulate the expression of PpLOB1.  Taken together, our findings revealed a novel regulatory module involving PpNAP4 and PpLOB1 that modulates peach fruit softening.  

Keywords:  LOB/LBD       PpLOB1        PpNAP4        peach        softening  
Received: 08 November 2024   Accepted: 26 January 2025 Online: 20 February 2025  
Fund: 

This work was supported by grants from the China Postdoctoral Science Foundation (2023M742867), the High-level Innovation and Entrepreneurship Talents Program of QinChuangYuan, Shaanxi Province, China (QCYRCXM-2022-234) and the National Key R&D Program of China (2019YFD1000203). 

About author:  #Correspondence Yanan Hu, E-mail: huyn@nwafu.edu.cn

Cite this article: 

Jieyu Dai, Ze Xu, Qianjin Zhan, Jingwen Zhu, Lijun Cao, Zhanling Lu, Yuting Xu, Tongyang Kang, Yanan Hu, Caiping Zhao. 2026. Genome-wide identification of the peach LOB/LBD genes and the positive role of the PpNAP4–PpLOB1 module in peach fruit softening. Journal of Integrative Agriculture, 25(3): 977-988.

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