Dong Xiangxiang, Li Yanjun, Guan Yuhan, Wang Shaoxi, Luo He, Li Xiaoming, Li He, Zhang Zhihong
Liaoning Key Laboratory of Strawberry Breeding and Cultivation, College of Horticulture, Shenyang Agricultural University, Shenyang, 110866, China.
Analytical and Testing Center, Shenyang Agricultural University, Shenyang, 110866, China.
Hortic Res. 2021 May 1;8(1):115. doi: 10.1038/s41438-021-00550-x.
Flowering time is known to be regulated by numerous pathways, such as the autonomous, gibberellin, aging, photoperiod-mediated, and vernalization pathways. These regulatory mechanisms involve both environmental triggers and endogenous hormonal cues. Additional flowering control mechanisms mediated by other phytohormones, such as auxin, are less well understood. We found that in cultivated strawberry (Fragaria × ananassa), the expression of auxin response factor4 (FaARF4) was higher in the flowering stage than in the vegetative stage. Overexpression of FaARF4 in Arabidopsis thaliana and woodland strawberry (Fragaria vesca) resulted in transgenic plants flowering earlier than control plants. In addition, FveARF4-silenced strawberry plants showed delayed flowering compared to control plants, indicating that FaARF4 and FveARF4 function similarly in regulating flowering. Further studies showed that ARF4 can bind to the promoters of the floral meristem identity genes APETALA1 (AP1) and FRUITFULL (FUL), inducing their expression and, consequently, flowering in woodland strawberry. Our studies reveal an auxin-mediated flowering pathway in strawberry involving the induction of ARF4 expression.
众所周知，开花时间受多种途径调控，如自主途径、赤霉素途径、衰老途径、光周期介导途径和春化途径。这些调控机制涉及环境触发因素和内源性激素信号。由其他植物激素（如生长素）介导的额外开花控制机制则了解较少。我们发现，在栽培草莓（Fragaria × ananassa）中，生长素响应因子4（FaARF4）在开花期的表达高于营养生长期。在拟南芥和森林草莓（Fragaria vesca）中过表达FaARF4导致转基因植物比对照植物开花更早。此外，与对照植物相比，FveARF4沉默的草莓植株开花延迟，这表明FaARF4和FveARF4在调控开花方面功能相似。进一步研究表明，ARF4可以与花分生组织特征基因APETALA1（AP1）和FRUITFULL（FUL）的启动子结合，诱导它们的表达，从而使森林草莓开花。我们的研究揭示了草莓中一条由生长素介导的开花途径，该途径涉及ARF4表达的诱导。
