Cheng Yajiao, Tremblay Benjamin J M, Balanzà Vicente, Larran Alvaro S, Qüesta Julia I
Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Campus UAB, Bellaterra, Barcelona 08193, Spain.
Instituto de Biología Molecular y Celular de Plantas (IBMCP), Consejo Superior de Investigaciones Científicas-Universitat Politècnica de València (CSIC-UPV), Valencia 46022, Spain.
Plant Physiol. 2025 May 30;198(2). doi: 10.1093/plphys/kiaf160.
The transition to reproductive development is a critical step in the plant lifecycle and relies on the integration of intrinsic and environmental signals. Several different pathways controlling flowering time function downstream of the perception of environmental cues such as day length (photoperiodic pathway) and seasonal temperature (vernalization and ambient temperature pathways). In addition, the phytohormone gibberellin (GA) induces the floral transition under noninductive photoperiod. In the model plant Arabidopsis (Arabidopsis thaliana), the transcriptional repressor VIVIPAROUS1/ABSCISIC ACID INSENTIVE3 (ABI3)-LIKE1 (VAL1) triggers the stable repression of the floral repressor FLOWERING LOCUS C (FLC) during vernalization. However, the involvement of VAL1 in other flowering pathways remains unclear. In this work, we combined genetic and transcriptomic approaches to investigate the requirement of VAL1 for flowering activation under different day lengths. We found that VAL1, but not its sister protein VAL2, is required to induce the floral transition both under long and short days. The delayed flowering time of val1 mutant plants was fully bypassed by exogenous GA application. We demonstrated that VAL1-mediated induction of flowering occurs partially via the direct epigenetic repression of the organ boundary genes BLADE-ON-PETIOLE1 (BOP1) and BOP2. Our work thus expands the repertoire of VAL target genes and further demonstrates the pleiotropic role of VAL factors in regulating Arabidopsis development.
向生殖发育的转变是植物生命周期中的关键一步，它依赖于内在信号和环境信号的整合。几条控制开花时间的不同途径在诸如日长（光周期途径）和季节温度（春化作用和环境温度途径）等环境线索的感知下游发挥作用。此外，植物激素赤霉素（GA）在非诱导性光周期下诱导开花转变。在模式植物拟南芥中，转录抑制因子VIVIPAROUS1/脱落酸不敏感3（ABI3）-LIKE1（VAL1）在春化作用期间触发对开花抑制因子开花位点C（FLC）的稳定抑制。然而，VAL1在其他开花途径中的作用仍不清楚。在这项工作中，我们结合遗传和转录组学方法来研究VAL1在不同日长下对开花激活的需求。我们发现，无论是在长日照还是短日照下，诱导开花转变都需要VAL1，而不是其姊妹蛋白VAL2。外源施用GA完全绕过了val1突变体植株延迟的开花时间。我们证明，VAL1介导的开花诱导部分是通过对器官边界基因叶片柄1（BOP1）和BOP2的直接表观遗传抑制来实现的。因此，我们的工作扩展了VAL靶基因的范围，并进一步证明了VAL因子在调节拟南芥发育中的多效性作用。
