A Divergent Clade KAI2 Protein in the Root Parasitic Plant Orobanche minor Is a Highly Sensitive Strigolactone Receptor and Is Involved in the Perception of Sesquiterpene Lactones.
A Divergent Clade KAI2 Protein in the Root Parasitic Plant Orobanche minor Is a Highly Sensitive Strigolactone Receptor and Is Involved in the Perception of Sesquiterpene Lactones.
复制标题
根寄生植物小列当中的分化分支 KAI2 蛋白是一种高度敏感的独脚金内酯受体，参与倍半萜内酯的感知。
DOI：
10.1093/pcp/pcad026
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发表时间：
2023
影响因子：
4.9
通讯作者：
Seto,Yoshiya
中科院分区：
文献类型：
--
作者：
Takei,Saori;Uchiyama,Yuta;Bürger,Marco;Suzuki,Taiki;Okabe,Shoma;Chory,Joanne;Seto,Yoshiya
独脚金内酯（SL）最初被发现作为根寄生植物的萌发诱导剂。2015年，三个研究小组独立报告了根寄生植物Striga hermonthica中SL受体的特征，该植物对作物生产造成重大损害，特别是在撒哈拉以南非洲。表征的受体属于对光低敏感/Karrikin不敏感2（HTL/KAI 2），其是α/β-水解酶蛋白超家族的成员。在非寄生植物中，HTL/KAI 2感知烟雾衍生的萌发诱导剂karrikin和尚未鉴定的内源性配体。然而，根寄生植物进化出一个特定的HTL/KAI 2分支，该分支已从非寄生植物的KAI 2分支中分化出来。帖前HermonthicaSL受体包括在这个特定的分支中，其被称为KAI 2分歧（KAI 2d）。小列当是专性根全寄生植物，由于缺乏光合能力，其生长完全依赖于宿主的水和营养。以前的系统发育分析KAI 2蛋白在O. minor已经证明存在至少五个KAI 2dclade基因。在此，我们报告KAI 2d 3和KAI 2d 4在O中。小分子具有作为SL受体的能力。它们在体外直接与SL相互作用，并且当在拟南芥中表达时，它们响应于合成的SL类似物GR 24而拯救热抑制的萌发。特别是，KAI 2d 3在拟南芥中表达时对GR 24表现出高敏感性，这表明该受体能够在O中高度敏感地识别SL。此外，我们提供的证据表明，这些KAI 2d受体参与感知倍半萜内酯，非独脚金内酯型发芽诱导剂。
Strigolactones (SLs) were initially discovered as germination inducers for root parasitic plants. In 2015, three groups independently reported the characterization of the SL receptor in the root parasitic plantStriga hermonthica, which causes significant damage to crop production, particularly in sub-Saharan Africa. The characterized receptors belong to HYPOSENSITIVE TO LIGHT/KARRIKIN INSENSITIVE2 (HTL/KAI2), which is a member of the α/β-hydrolase protein superfamily. In non-parasitic plants, HTL/KAI2 perceives the smoke-derived germination inducer karrikin and a yet-unidentified endogenous ligand. However, root parasitic plants evolved a specific clade of HTL/KAI2 that has diverged from the KAI2 clade of non-parasitic plants. TheS. hermonthicaSL receptors are included in this specific clade, which is called KAI2 divergent (KAI2d).Orobanche minoris an obligate root holoparasitic plant that grows completely dependent on the host for water and nutrients because of a lack of photosynthetic ability. Previous phylogenetic analysis of KAI2 proteins inO. minorhas demonstrated the presence of at least fiveKAI2dclade genes. Here, we report that KAI2d3 and KAI2d4 inO. minorhave the ability to act as the SL receptors. They directly interact with SLs in vitro, and when expressed inArabidopsis, they rescue thermo-inhibited germination in response to the synthetic SL analog GR24. In particular, KAI2d3 showed high sensitivity to GR24 when expressed inArabidopsis, suggesting that this receptor enables highly sensitive SL recognition inO. minor.Furthermore, we provide evidence that these KAI2d receptors are involved in the perception of sesquiterpene lactones, non-strigolactone-type germination inducers.