School of Bioscience & Bioengineering, South China University of Technology, Guangzhou 510006, China; State Key Laboratory of Applied Microbiology, South China (The Ministry-Province Joint Development), Guangdong Institute of Microbiology, Guangzhou 510070, China.
Gene. 2013 Dec 10;532(1):63-71. doi: 10.1016/j.gene.2013.09.014. Epub 2013 Sep 17.
Amanita exitialis is a lethal mushroom that was first discovered in Guangdong Province, China. The high content of amanitin in its basidiocarps makes it lethal to humans. To comprehensively characterize the A. exitialis transcriptome and analyze the Amanita toxins as well as their related gene family, transcriptome sequencing of A. exitialis was performed using Illumina HiSeq 2000 technology. A total of 25,563,688 clean reads were collected and assembled into 62,137 cDNA contigs with an average length of 481 bp and N50 length of 788 bp. A total of 27,826 proteins and 39,661 unigenes were identified among the assembled contigs. All of the unigenes were classified into 166 functional categories for understanding the gene functions and regulation pathways. The genes contributing to toxic peptide biosynthesis were analyzed. From this set, eleven gene sequences encoding the toxins or related cyclic peptides were discovered in the transcriptome. Three of these sequences matched the peptide toxins α-amanitin, β-amanitin, and phallacidin, while others matched amanexitide and seven matched unknown peptides. All of the genes encoding peptide toxins were confirmed by polymerase chain reaction (PCR) in A. exitialis, and the phylogenetic relationships among these proprotein sequences were discussed. The gene polymorphism and degeneracy of the toxin encoding sequences were found and analyzed. This study provides the first primary transcriptome of A. exitialis, which provided comprehensive gene expression information on the lethal amanitas at the transcriptional level, and could lay a strong foundation for functional genomics studies in those fungi.
致命鹅膏（Amanita exitialis）是一种首次在中国广东省发现的剧毒蘑菇。其担子果中含有高浓度的鹅膏肽类毒素，对人类具有致命性。为了全面描绘致命鹅膏的转录组特征，并分析鹅膏毒素及其相关基因家族，本研究采用 Illumina HiSeq 2000 技术对其进行转录组测序。共收集到 25563688 条清洁reads，组装成 62137 条 cDNA 序列，平均长度为 481 bp，N50 长度为 788 bp。在组装的序列中鉴定出 27826 个蛋白质和 39661 个 unigenes。所有的 unigenes被分为 166 个功能类别，以了解基因的功能和调控途径。分析了与有毒肽生物合成相关的基因。从这些基因中，在转录组中发现了 11 个编码毒素或相关环肽的基因序列。其中三个序列与α-鹅膏肽、β-鹅膏肽和鬼笔环肽的毒素匹配，其他序列与 amanexitide 匹配，还有七个序列与未知肽匹配。通过聚合酶链式反应（PCR）在致命鹅膏中验证了所有编码肽毒素的基因，并讨论了这些前蛋白序列的系统发育关系。发现并分析了毒素编码序列的基因多态性和简并性。本研究提供了致命鹅膏的首个初级转录组，为鹅膏属真菌在转录水平上提供了全面的基因表达信息，为这些真菌的功能基因组学研究奠定了坚实的基础。
