Flowering is crucial to plant reproduction and controlled by multiple factors. However, the mechanisms underlying the regulation of flowering in perennial plants are still largely unknown. Here, we first report a super long blooming 1 (slb1) mutant of the relict tree Liriodendron chinense possessing a prolonged blooming period of more than 5 months, in contrast to the 1 month blooming period in the wild type (WT). Phenotypic characterization showed that earlier maturation of lateral shoots was caused by accelerated axillary bud fate, leading to the phenotype of continuous flowering in slb1 mutants. The transcriptional activity of genes related to hormone signaling (auxin, cytokinin, and strigolactone), nutrient availability, and oxidative stress relief further indicated active outgrowth of lateral buds in slb1 mutants. Interestingly, we discovered a unique FT splicing variant with intron retention specific to slb1 mutants, representing a potential causal mutation in the slb1 mutants. Surprisingly, most slb1 inbred offspring flowered precociously with shorter juvenility (~4 months) than that (usually 8–10 years) required in WT plants, indicating heritable variation underlying continuous flowering in slb1 mutants. This study reports an example of a perennial tree mutant that flowers continuously, providing a rare resource for both breeding and genetic research.

中文翻译：

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形态学、物候学和转录分析提供了对遗存木本植物鹅掌楸突变体多样化开花性状的深入了解

开花对植物繁殖至关重要，受多种因素控制。然而，多年生植物开花调控的机制仍然很大程度上未知。在这里，我们首先报告一个超长开花1(slb1) 孑遗树的突变体鹅掌楸与野生型（WT）的1个月开花期相比，具有超过5个月的延长开花期。表型表征表明，侧枝较早成熟是由加速的腋芽命运引起的，导致连续开花的表型。slb1突变体。与激素信号（生长素、细胞分裂素和独脚金内酯）、营养可用性和氧化应激缓解相关的基因的转录活性进一步表明侧芽的活跃生长slb1突变体。有趣的是，我们发现了一个独特的英尺具有特定于内含子保留的剪接变体slb1突变体，代表潜在的因果突变slb1突变体。令人惊讶的是，大多数slb1近交后代早熟开花，幼龄期（约 4 个月）比 WT 植物所需的幼龄期（通常 8-10 年）短，表明在 WT 植物中持续开花的遗传变异slb1突变体。这项研究报告了一个多年生树木突变体的例子，它不断开花，为育种和遗传研究提供了稀有资源。