Phalaenopsis aphrodite can be induced to initiate spike growth and flowering by exposure to low ambient temperatures. However, the factors and mechanisms responsible for spike initiation in P. aphrodite remain largely unknown. In this study, we show that a repressor FLOWERING LOCUS T-like gene, FTL, can act as a negative regulator of spike initiation in P. aphrodite. The mRNA transcripts of PaFTL are consistently high during high ambient temperature, thereby preventing premature spike initiation. However, during low ambient temperature, PaFTL expression falls while FLOWERING LOCUS T (FT) expression increases, allowing for spike initiation. Knock-down of PaFTL expression through virus-inducing gene silencing (VIGS) promoted spike initiation at 30/28°C. Moreover, PaFTL interacts with FLOWERING LOCUS D (FD) in a similar manner to FT, to regulate downstream flowering initiation genes. Transgenic P. aphrodite plants exhibiting high expression of PaFTL do not undergo spike initiation, even when exposed to low ambient temperatures. These findings shed light on the flowering mechanisms in Phalaenopsis and provide new insights into how perennial plants govern spike initiation in response to temperature cues.

中文翻译：

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温度调节开花位点 T Like 基因协调蝴蝶兰花穗起始

通过暴露在低环境温度下，可以诱导蝴蝶兰开始穗生长和开花。然而，导致 P. aphrodite 中尖峰启动的因素和机制仍然很大程度上未知。在这项研究中，我们证明了 FLOWERING LOCUS T 样阻遏基因 FTL 可以作为 P. aphrodite 中尖峰起始的负调节因子。PaFTL 的 mRNA 转录本在高环境温度下始终保持较高水平，从而防止过早启动尖峰。然而，在低环境温度下，PaFTL 表达下降，而 FLOWERING LOCUS T (FT) 表达增加，从而允许尖峰启动。通过病毒诱导基因沉默 (VIGS) 敲低 PaFTL 表达可促进 30/28°C 下的尖峰起始。此外，PaFTL 以与 FT 类似的方式与 FLOWERING LOCUS D (FD) 相互作用，以调节下游的开花起始基因。即使暴露在低环境温度下，表现出高PaFTL表达的转基因阿芙罗狄蒂植物也不会经历穗起始。这些发现揭示了蝴蝶兰的开花机制，并为多年生植物如何响应温度信号控制穗的启动提供了新的见解。