Two Likely Auto-Tetraploidization Events Shaped Kiwifruit Genome and Contributed to Establishment of the Actinidiaceae Family

First author: Jin-Peng Wang; Affiliations: North China University of Science and Technology (华北理工大学): Tangshan, China

Corresponding author: Xiyin Wang(王希胤)

The genome of kiwifruit (Actinidia chinensis; 猕猴桃) was sequenced previously, the first in the Actinidiaceae family (猕猴桃科). It was shown to have been affected by polyploidization events, the nature of which has been elusive. Here, we performed a reanalysis of the genome and found clear evidence of 2 tetraploidization events, with one occurring ~50-57 million years ago (Mya) and the other ~18-20 Mya. Two subgenomes produced by each event have been under balanced fractionation. Moreover, genes were revealed to express in a balanced way between duplicated copies of chromosomes. Besides, lowered evolutionary rates of kiwifruit genes were observed. These findings could be explained by the likely auto-tetraploidization nature of the polyploidization events. Besides, we found that polyploidy contributed to the expansion of key functional genes, e.g., vitamin C biosynthesis genes. The present work also provided an important comparative genomics resource in the Actinidiaceae and related families.

猕猴桃基因组是猕猴桃科中第一个报道基因组的物种。之前的研究显示猕猴桃基因组受到了多倍化事件的影响，但具体的细节仍然不清楚。本文对猕猴桃基因组进行了再分析，发现猕猴桃基因组经历了两次四倍化事件，一次在50~57个百万年之前，一次在18~20个百万年之前。两次全基因组复制事件所产生的亚基因组经历了平均的片段化。此外，由于染色体复制所产生的基因拷贝的表达也不存在偏性。作者还发现了猕猴桃基因的演化速率较低。这些发现可能是由于猕猴桃的多倍化事件是自发四倍化加倍所导致的。另外，作者还发现了猕猴桃多倍化事件促进了维生素C生物合成相关基因的扩张。本文同时还对猕猴桃科与邻近科的物种进行了比较基因组的研究。

通讯：王希胤（http://bio.ncst.edu.cn/col/1460771460061/2016/04/19/1461037268201.html）

个人简介：1991-1995年，吉林大学，数学学士；2000-2005年，北京大学，生物信息学博士；2006-2009年，美国乔治亚大学，博士后。

研究方向：生物信息学软件和数据库开发，染色体进化理论创新，基因组多倍化与稳定性研究，重要经济作物全基因组比对算法和应用研究，基因家族和调控网络研究。

doi: https://doi.org/10.1016/j.isci.2018.08.003

Journal: iScience

Published date: 28 September, 2018

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