Featured Research

from universities, journals, and other organizations

Large-scale deep re-sequencing reveals cucumber's evolutionary enigma

Date:
October 20, 2013
Source:
BGI Shenzhen
Summary:
Scientists have created a cucumber genomic variation map that includes about 3.6 million variants revealed by deep resequencing of 115 cucumbers worldwide. This work provides new insights for understanding the genetic basis of domestication and diversity of this important crop, and provides guidance for breeders to harness genetic variation for crop improvement.

The cucumber is a major vegetable crop consumed worldwide Gurken Pflanze.
Credit: © Swetlana Wall / Fotolia

In a collaborative study published online today in Nature Genetics, researchers from the Genome Centre of Chinese Academy of Agricultural Sciences (CAAS), BGI, and other institutes present a cucumber genomic variation map that includes about 3.6 million variants revealed by deep resequencing of 115 cucumbers worldwide. This work provides new insights for understanding the genetic basis of domestication and diversity of this important crop, and provides guidance for breeders to harness genetic variation for crop improvement.

Cucumber is a major vegetable crop consumed worldwide as well as a model system for sex determination and plant vascular biology. In 2009, cucumber became the seventh plant to have its genome sequence published, following the well-studied model plant Arabidopsis thaliana, the poplar tree, grapevine, papaya, and the crops rice and sorghum. More efforts have been put into cucumber genomics research since then.

As a part of these efforts, researchers from CAAS and BGI re-sequenced 115 cucumber lines sampled from 3,342 accessions worldwide, and also conducted de novo sequencing on a wild cucumber. In total, they detected more than 3.3 million SNPs, over 0.33 million small insertion and deletions (indels), and 594 presence-absence variations (PAVs), and then constructed a comprehensive variation map of cucumber.

Furthermore, researchers did a suite of model-based analyses of population structure and phylogenetic reconstruction. The results indicated that the three cultivated groups (Eurasian, East Asian, and Xishuangbanna) each are monophyletic and genetically quite homogeneous, but the Indian group shows clear evidence of substructure and genetic heterogeneity. Their further analysis also provide evidence on the ancestral status of the Indian group, which holds great potential for introducing new alleles into the cultivated gene pool.

To understand the population bottlenecks during domestication, researchers made a comparison analysis between vegetable and grain food crops. The comparison result indicated that the three vegetable crops (cucumber, watermelon, and tomato) probably underwent narrower bottleneck events during domestication than the grain food crops (rice, maize, and soybean). In addition, they also identified 112 putative domestication sweeps in the cucumber genome. These findings provide additional impetus for the use of wild germplasm in future vegetable breeding.

Wild cucumber is an extremely bitter fruit. An essential step in the domestication of the wild cucumber into a eatable vegetable must have degenerated its bitter taste. Two genetic loci, Bi and Bt, are known to confer bitterness in cucumber. In this study, researchers found that the Bt locus was delimited to a 442-kb region on chromosome 5 that harbors 67 predicted genes.

They further investigated the genomic basis of divergence among the cultivated populations for identifying genes controlling important traits. The most obvious trait is the orange endocarp, which distinguishes the Xishuangbanna group from the other groups. This trait is caused by the accumulation of large amounts of β-carotene that was reported to be controlled by a single recessive gene ore. In this study, researchers discovered a key natural variation in a β-carotene hydroxylase gene that could be used to breed cucumber with enhanced nutritional value.

Xin Liu, Project Manager from BGI, said "This study not only generates valuable genomic resource including additional wild reference genome, genome-wide variations for further studies and breeding applications on cucumber, but also gave us a better picture about how the cucumber genome evolved during domestication. It is also a good example for studies on vegetable or other economic crops. Large scale sequencing approach and genome wide analysis can be applied on different economic crops for better understanding their evolutionary process and specific traits, providing unique opportunities for further applications."


Story Source:

The above story is based on materials provided by BGI Shenzhen. Note: Materials may be edited for content and length.


Journal Reference:

  1. Jianjian Qi, Xin Liu, Di Shen, Han Miao, Bingyan Xie, Xixiang Li, Peng Zeng, Shenhao Wang, Yi Shang, Xingfang Gu, Yongchen Du, Ying Li, Tao Lin, Jinhong Yuan, Xueyong Yang, Jinfeng Chen, Huiming Chen, Xingyao Xiong, Ke Huang, Zhangjun Fei, Linyong Mao, Li Tian, Thomas Stδdler, Susanne S Renner, Sophien Kamoun, William J Lucas, Zhonghua Zhang, Sanwen Huang. A genomic variation map provides insights into the genetic basis of cucumber domestication and diversity. Nature Genetics, 2013; DOI: 10.1038/ng.2801

Cite This Page:

BGI Shenzhen. "Large-scale deep re-sequencing reveals cucumber's evolutionary enigma." ScienceDaily. ScienceDaily, 20 October 2013. <www.sciencedaily.com/releases/2013/10/131020160735.htm>.
BGI Shenzhen. (2013, October 20). Large-scale deep re-sequencing reveals cucumber's evolutionary enigma. ScienceDaily. Retrieved October 20, 2014 from www.sciencedaily.com/releases/2013/10/131020160735.htm
BGI Shenzhen. "Large-scale deep re-sequencing reveals cucumber's evolutionary enigma." ScienceDaily. www.sciencedaily.com/releases/2013/10/131020160735.htm (accessed October 20, 2014).

Share This



More Plants & Animals News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

White Lion Cubs Born in Belgrade Zoo

White Lion Cubs Born in Belgrade Zoo

AFP (Oct. 20, 2014) — Two white lion cubs, an extremely rare subspecies of the African lion, were recently born at Belgrade Zoo. They are being bottle fed by zoo keepers after they were rejected by their mother after birth. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com
Traditional Farming Methods Gaining Ground in Mali

Traditional Farming Methods Gaining Ground in Mali

AFP (Oct. 20, 2014) — He is leading a one man agricultural revolution in Mali - Oumar Diatabe uses traditional farming methods to get the most out of his land and is teaching others across the country how to do the same. Duration: 01:44 Video provided by AFP
Powered by NewsLook.com
Goliath Spider Will Give You Nightmares

Goliath Spider Will Give You Nightmares

Buzz60 (Oct. 20, 2014) — An entomologist stumbled upon a South American Goliath Birdeater. With a name like that, you know it's a terrifying creepy crawler. Sean Dowling (@SeanDowlingTV) has the details. Video provided by Buzz60
Powered by NewsLook.com
Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

3BL Media (Oct. 20, 2014) — Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-fuel Impala Video provided by 3BL
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins