Key message

The cytokinin pathway promotes the initiation of bulbil formation, and iPA may an important type of cytokinin during bulbil formation in Lilium lancifolium.

Abstract

Bulbils are important vegetative reproductive organs in triploid Lilium lancifolium. We previously showed that cytokinins are involved in bulbil formation, but how cytokinins participate in bulbil formation is not clear. In this study, bulbil formation was divided into three stages on the basis of anatomical and histological observations: the bulbil initiation stage, bulbil primordium-formation stage and bulbil structure-formation stage. The results indicated that iPA was the most critical cytokinin during the bulbil initiation. qRT-PCR revealed that increased iPA content during bulbil initiation was mainly due to increased expression of cytokinin synthesis genes (IPT1/5) and cytokinin activation genes (LOG1/3/5/7) and significantly decreased expression of the cytokinin degradation gene CKX4. Exogenous 6-BA and lovastatin affected the cytokinin pathway and promoted or inhibited bulbil initiation by increasing or decreasing the content of endogenous iPA, respectively. In summary, we demonstrate that cytokinins positively regulate bulbil formation and provide preliminary insight into the regulatory mechanisms by which the cytokinin pathway promotes bulbil initiation.

中文翻译：

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外源性细胞分裂素在体外诱导长叶百合球茎形成的机制。

关键信息

细胞分裂素途径促进球茎形成的起始，iPA可能是兰花百合球茎形成过程中重要的细胞分裂素类型。

抽象的

鳞茎是三倍体长叶百合中重要的营养生殖器官。我们之前表明细胞分裂素参与球茎形成，但细胞分裂素如何参与球茎形成尚不清楚。本研究根据解剖学和组织学观察将鳞茎形成分为三个阶段：鳞茎起始阶段、鳞茎原基形成阶段和鳞茎结构形成阶段。结果表明，iPA是珠芽萌发过程中最关键的细胞分裂素。qRT-PCR 显示，在球茎起始期间 iPA 含量增加主要是由于细胞分裂素合成基因 ( IPT1 / 5 ) 和细胞分裂素激活基因 ( LOG1 / 3 ) 的表达增加。/ 5 / 7 ) 并显着降低细胞分裂素降解基因CKX4的表达。外源性 6-BA 和洛伐他汀影响细胞分裂素途径，并分别通过增加或减少内源性 iPA 的含量来促进或抑制珠芽的起始。总之，我们证明细胞分裂素正向调节珠芽形成，并初步了解细胞分裂素途径促进珠芽起始的调节机制。