Novel family of terpene synthases evolved from trans-isoprenyl diphosphate synthases in a flea beetle
Novel family of terpene synthases evolved from trans-isoprenyl diphosphate synthases in a flea beetle
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DOI：
10.1073/pnas.1523468113
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发表时间：
2016-03-15
影响因子：
11.1
通讯作者：
Koellner, Tobias G.
中科院分区：
文献类型：
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作者：
Beran, Franziska;Rahfeld, Peter;Koellner, Tobias G.
倍半萜在昆虫的交流中起着重要的作用，例如作为信息素。然而，迄今为止，还没有在昆虫中发现参与构建基本碳骨架的倍半萜合成酶。本文研究了十字花科跳甲（Phyllotreta striolata）中倍半萜(6R,7S)-himachala-9,11-二烯的生物合成，该化合物先前被认为是几种跳甲中雄性产生的聚集信息素。在甲虫粗蛋白提取物中检测到A (6R, 7S)-himachala-9,11-二烯产倍半萜合成酶活性，但仅当（Z，E）-法尼酯二磷酸[(Z，E)-FPP]作为底物时。在P. striolata转录组中没有发现类似于植物、真菌或细菌的倍半萜合成酶序列，但我们鉴定了9个不同的推定反式异戊二烯二磷酸合成酶（trans-IDS）转录本。其中四种推测的反式idss在异种表达时表现出萜烯合成酶（TPS）活性。重组PsTPS1将（Z，E）-FPP转化为(6R,7S)-himachala-9,11-二烯和其他在甲虫提取物中观察到的倍半萜。rnai介导的ppstps1 mRNA敲低导致雄性黄斑鱼聚集信息素的释放减少，证实了ppstps1在信息素生物合成中的重要作用。两个表达的酶显示出真正的IDS活性，PsIDS1合成（E，E）-FPP，而PsIDS3产生neryl二磷酸，（Z，Z）-FPP和（Z，E）-FPP。在系统发育分析中，pps酶和PsIDS3从已知的鞘翅目反式ids酶（包括PsIDS1和PsIDS2）分支中分离出来。然而，黄曲藻的IDS和TPS基因的外显子-内含子结构是保守的，这表明该TPS基因家族是从跨IDS祖先进化而来的。
Sesquiterpenes play important roles in insect communication, for example as pheromones. However, no sesquiterpene synthases, the enzymes involved in construction of the basic carbon skeleton, have been identified in insects to date. We investigated the biosynthesis of the sesquiterpene (6R,7S)-himachala-9,11-diene in the crucifer flea beetle Phyllotreta striolata, a compound previously identified as a male-produced aggregation pheromone in several Phyllotreta species. A (6R, 7S)-himachala-9,11-diene-producing sesquiterpene synthase activity was detected in crude beetle protein extracts, but only when (Z,E)-farnesyl diphosphate [(Z,E)-FPP] was offered as a substrate. No sequences resembling sesquiterpene synthases from plants, fungi, or bacteria were found in the P. striolata transcriptome, but we identified nine divergent putative trans-isoprenyl diphosphate synthase (trans-IDS) transcripts. Four of these putative trans-IDSs exhibited terpene synthase (TPS) activity when heterologously expressed. Recombinant PsTPS1 converted (Z,E)-FPP to (6R,7S)-himachala-9,11-diene and other sesquiterpenes observed in beetle extracts. RNAi-mediated knockdown of PsTPS1 mRNA in P. striolata males led to reduced emission of aggregation pheromone, confirming a significant role of PsTPS1 in pheromone biosynthesis. Two expressed enzymes showed genuine IDS activity, with PsIDS1 synthesizing (E,E)-FPP, whereas PsIDS3 produced neryl diphosphate, (Z,Z)-FPP, and (Z,E)-FPP. In a phylogenetic analysis, the PsTPS enzymes and PsIDS3 were clearly separated from a clade of known coleopteran trans-IDS enzymes including PsIDS1 and PsIDS2. However, the exon-intron structures of IDS and TPS genes in P. striolata are conserved, suggesting that this TPS gene family evolved from trans-IDS ancestors.