The Interaction between DELLA and ARF/IAA Mediates Crosstalk between Gibberellin and Auxin Signaling to Control Fruit Initiation in Tomato
The Interaction between DELLA and ARF/IAA Mediates Crosstalk between Gibberellin and Auxin Signaling to Control Fruit Initiation in Tomato
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DOI：
10.1105/tpc.18.00363
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发表时间：
2018-08-01
期刊：
影响因子：
11.6
通讯作者：
Sun, Tai-ping
中科院分区：
文献类型：
--
作者：
Hu, Jianhong;Israeli, Alon;Sun, Tai-ping
被子植物受精后的果实形成受植物激素的严格调控。在番茄（Solanum lycopersicum）中，生长素和赤霉素（gibberellin， GA）在促进果实形成中起着核心作用。在没有受精的情况下，升高的GA或生长素信号可以诱导孤雌核（无籽果实生产）。ga信号抑制因子SlDELLA和生长素信号组件SlIAA9和SlARF7抑制孤雌生殖，但潜在的机制尚不清楚。在这里，我们发现SlDELLA和SlARF7/SlIAA9复合物介导GA和生长素途径之间的串扰，以调节果实形成。酵母双杂交和共免疫沉淀实验表明，SlARF7和额外的激活剂SlARFs通过不同的结构域与SlDELLA和SlIAA9相互作用。SlARF7/SlIAA9和SlDELLA拮抗GA和生长素代谢相关反馈调控基因的表达，而SlARF7/SlIAA9和SlDELLA共同调控果实生长相关基因的表达。对procera （della）、SlARF7 RNAi（下调多个激活因子slarf的表达）和整个（iaa9）单、双突变体的分析表明，这些基因加在一起影响孤雌结实，支持SlARFs/SlIAA9和SlDELLA互作在调节果实形成过程中发挥重要作用的观点。对GA缺乏突变体gib1的分析表明，生长素诱导的果实形成需要活跃的GA生物合成和信号传导。我们的研究揭示了生长素和ga信号组分之间的直接串扰对番茄果实形成至关重要。
Fruit initiation following fertilization in angiosperms is strictly regulated by phytohormones. In tomato (Solanum lycopersicum), auxin and gibberellin (GA) play central roles in promoting fruit initiation. Without fertilization, elevated GA or auxin signaling can induce parthenocarpy (seedless fruit production). The GA-signaling repressor SlDELLA and auxin-signaling components SlIAA9 and SlARF7 repress parthenocarpy, but the underlying mechanism is unknown. Here, we show that SlDELLA and the SlARF7/SlIAA9 complex mediate crosstalk between GA and auxin pathways to regulate fruit initiation. Yeast-two-hybrid and coimmunoprecipitation assays showed that SlARF7 and additional activator SlARFs interact with SlDELLA and SlIAA9 through distinct domains. SlARF7/SlIAA9 and SlDELLA antagonistically modulate the expression of feedback-regulated genes involved in GA and auxin metabolism, whereas SlARF7/SlIAA9 and SlDELLA coregulate the expression of fruit growth-related genes. Analysis of procera (della), SlARF7 RNAi (with downregulated expression of multiple activator SlARFs), and entire (iaa9) single and double mutants indicated that these genes additively affect parthenocarpy, supporting the notion that the SlARFs/SlIAA9 and SlDELLA interaction plays an important role in regulating fruit initiation. Analysis of the GA-deficient mutant gib1 showed that active GA biosynthesis and signaling are required for auxin-induced fruit initiation. Our study reveals how direct crosstalk between auxin- and GA-signaling components is critical for tomato fruit initiation.