天麻种子共生萌发中SCPL基因的克隆与分析

Cloning and Analysis of SCPL Gene in Symbiotic Germination of Gastrodia elata Seed

天麻种子细小,无胚乳,自然条件下需与内生真菌共生才能萌发。近年来,研究发现丝氨酸羧肽酶(serine carboaypeptidase,SCP)及其类蛋白(serine carboaypeptidase-like proteins,SCPL)可以参与种子萌发中储藏蛋白的水解,以及植物激素油菜素内酯和脱落酸的信号传导,在种子萌发的过程中具有重要作用。本研究以共生萌发的天麻(Gastrodia elata Bl.)种子为材料,采用RACE技术获得丝氨酸羧肽酶基因全长cDNA,命名为GeSCPL。该基因全长cDNA为1 665 bp,编码463个氨基酸。亚细胞定位显示该蛋白主要表达于胞外和液泡中,具有S10结构域,属于S10超家族,并存在4种修饰方式,可能属于羧肽酶C,且与其他科属植物的丝氨酸羧肽酶基因相似性较高。qPCR结果表明,在与真菌的共生萌发过程中,天麻原球茎中GeSCPL基因的表达量下降。本研究首次获得了天麻种子GeSCPL全长cDNA序列,为进一步研究天麻种子共生萌发的分子机制提供科学依据。

Seeds of Gastrodia elata are tiny and have no endosperm, which must depend on suitable endophytic fungi to germinate in natural conditions. In recent years, it has been found that serine carboaypeptidase（SCP） and serine carboaypeptidase-like proteins（SCPL） are involved in the hydrolysis of storage protein during seed germination and signal transduction of brassinosteroids and abscisic acid, which play an important role in the process of seed germination. In this study, the Gastrodia elata seed germinated through symbiotic germination were selected as the materials, and the full-length c DNA of SCP was obtained by RACE technology, which was named as Ge SCPL. The c DNA was 1 665 bp, encoding 463 amino acids. Sub-cellular location demonstrated that Ge SCPL protein mainly expressed outside or in the vacuole, which had S10 conserved domain and belonged to S10 superfamiliy. Ge SCPL protein had four protein modified ways, indicating that it might belong to carboaypeptidase C,and it had relatively high similarity with serine carboxypeptidase gene from other genera. The results of q PCR suggested that the expression of Ge SCPL gene from seeds of Gastrodia elata decreased during symbiotic germination with fungi. This study acquired the full length of c DNA sequence of Ge SCPL in Gastrodia elata seed, which could provide scientific reference for further study on the molecular mechanism of symbiotic germination in seeds of Gastrodia elata.