南湖新闻网讯（通讯员 张蒙玲）作物产量主要取决于收获器官的大小，揭示其调控机制是提升作物产量的关键。近日，油菜团队联合崖州湾国家实验室在Journal of Integrative Plant Biology发表了题为“12-hydroxylauric acid, a novel growth regulator, promotes plant organ development”的研究论文，该研究首次揭示12-羟基月桂酸作为BnaA09.CYP78A9的催化产物，是一种潜在的新型植物内源生长调节物质，可显著促进油菜、大豆、番茄和黄瓜等多种作物的果实和种子发育，展现出广阔的应用前景。

团队前期研究表明，CACTA-like转座子插入可显著上调BnaA09.CYP78A9基因表达，促进油菜角果伸长和籽粒增大。本研究进一步揭示，BnaA09.CYP78A9可将月桂酸（LA）转化为12-羟基月桂酸（12-HOLA），在长角果油菜品种中，12-HOLA的含量是短角果品种的5倍以上，表明12-HOLA与器官增大密切相关（图1）。

图1 BnaA09.CYP78A9酶活鉴定及12-羟基月桂酸含量检测

基于这一发现，研究团队假设并验证了12-HOLA具有促进器官生长的功能。在2022至2025年间，研究团队在湖北武汉、荆州以及海南三亚等多个试验点，对油菜、大豆、黄瓜和番茄开展了系统的田间喷施试验。结果显示，喷施60 ppm 12-HOLA后：油菜产量在不同品种和地点增产7.91%至30.82%；大豆增产30.14%；黄瓜增产24.37%，果实鲜重增加20.64%；番茄果实鲜重增加11.92%。以上结果表明，12-羟基月桂酸具有广谱促进生长的活性，在多种作物的增产增效中具有重要应用潜力（图2）。

图2 12-HOLA田间喷施处理促进多种作物产量提高

为了探究12-HOLA提高产量的分子机制，研究团队通过转录组学和生理生化分析发现，12-HOLA能迅速激活植物体内的生长素响应网络，上调YUC、PIN、EXPA等生长素合成、运输及信号传导相关基因的表达，促进细胞伸长。同时，12-HOLA还显著增强了油菜角果的碳代谢活性，为种子发育提供了更充足的物质和能量（图3）。

图3 12-HOLA促进油菜角果伸长的机制

综上，该研究不仅揭示了BnaA09.CYP78A9催化合成12-HOLA调控器官发育的分子机制，还首次发现12-HOLA作为一种天然、绿色植物生长调节物质的应用前景。同时为作物高产育种和精准调控提供了新策略，也为开发新型植物生长调节剂奠定了重要基础。

崖州湾国家实验室博士后彭妍和华中农业大学/崖州湾国家实验室联合培养博士研究生张蒙玲为本文共同第一作者，华中农业大学刘克徳教授和郭亮教授为共同通讯作者。该研究得到国家自然科学基金、国家杰出青年科学基金、武汉知识创新工程-基础研究、崖州湾国家实验室基础研究项目和中央高校基础研究基金的资助。

论文链接：https://onlinelibrary.wiley.com/doi/10.1111/jipb.70243

英文摘要：Crop yield is largely determined by the size of harvestable organs and understanding the mechanisms that govern organ size is therefore crucial for improving crop productivity. CYP78As are plant-specific subfamily of cytochrome P450 enzymes that have been identified as organ size regulators and are expressed in various plant organs. We previously identified BnaA09.CYP78A9, whose expression is markedly upregulated in long-silique cultivars by a CACTA-like transposable element (CTE) insertion in the regulatory region, acts as a pleiotropic regulator of yield-related traits in long-silique rapeseed varieties. Here, we show that BnaA09.CYP78A9+CTE is expressed predominantly in the siliques and seeds of rapeseed cultivar ZS11. cyp78a9-CRISPR knockout mutants exhibited reductions in silique length, seed size and seed number per silique. Enzyme assays revealed that BnaA09.CYP78A9 converts lauric acid (LA) to 12-hydroxylauric acid (12-HOLA) and endogenous metabolite quantification revealed 12-HOLA levels were 5.01-fold greater in long-silique materials versus short-silique materials. Application of exogenous 12-HOLA significantly increased silique/pod elongation and seed weight, enhancing yield per plant by 32.77% in Arabidopsis and yield per unit area by 7.91%–30.82% in rapeseed and 30.14% in soybean compared with controls, respectively. 12-HOLA application also stimulated fruit expansion in horticultural crops, increasing fresh fruit weight by 20.64%–22.96% in cucumber and 11.92%–24.13% in tomato. Transcriptome analyses revealed that 12-HOLA treatment upregulated the expression of genes involved in auxin biosynthesis, transport and signaling. 12-HOLA treatment not only rapidly activated numerous transcription factors but also thereby significantly promoted carbon metabolism within rapeseed siliques. Our study provides strong evidence that 12-HOLA produced by BnaA09.CYP78A9 activates the auxin pathway, promotes cell elongation and increases fruit size and seed weight. These findings highlight the potential use of 12-HOLA as a natural plant growth regulator and CYP78A9 as a target for gene editing and molecular breeding.

审核人：郭亮