Complete Chloroplast Genome Sequence and Comparative and Phylogenetic Analyses of the Cultivated Cyperus esculentus

Yongguo Zhao,Yuanyu Zhang,Qianqian Zhao,Dongquan Guo,Xiaofang Zhong,Jing Yang,Guojie Xing,Chunming Yang,Wei Ren,Lu Niu,Yang Cui,Xiangdong Yang

doi:10.3390/d13090405

Abstract

Cyperus esculentus produces large amounts of oil as one of the main oil storage reserves in underground tubers, making this crop species not only a promising resource for edible oil and biofuel in food and chemical industry, but also a model system for studying oil accumulation in non-seed tissues. In this study, we determined the chloroplast genome sequence of the cultivated C. esculentus (var. sativus Boeckeler). The results showed that the complete chloroplast genome of C. esculentus was 186,255 bp in size, and possessed a typical quadripartite structure containing one large single copy (100,940 bp) region, one small single copy (10,439 bp) region, and a pair of inverted repeat regions of 37,438 bp in size. Sequence analyses indicated that the chloroplast genome encodes 141 genes, including 93 protein-coding genes, 40 transfer RNA genes, and 8 ribosomal RNA genes. We also identified 396 simple-sequence repeats and 49 long repeats, including 15 forward repeats and 34 palindromes within the chloroplast genome of C. esculentus. Most of these repeats were distributed in the noncoding regions. Whole chloroplast genome comparison with those of the other four Cyperus species indicated that both the large single copy and inverted repeat regions were more divergent than the small single copy region, with the highest variation found in the inverted repeat regions. In the phylogenetic trees based on the complete chloroplast genomes of 13 species, all five Cyperus species within the Cyperaceae formed a clade, and C. esculentus was evolutionarily more related to C. rotundus than to the other three Cyperus species. In summary, the chloroplast genome sequence of the cultivated C. esculentus provides a valuable genomic resource for species identification, evolution, and comparative genomic research on this crop species and other Cyperus species in the Cyperaceae family.

Highlights

Cyperus esculentus L., known as yellow tigernut, yellow nutsedge, or chufa, is a perennial C4 plant in the sedge family (Cyperaceae), which is comprised of approximately species worldwide
We found that C. esculentus and C. rotundus contained the same genes in JLB and in JLA, whereas at similar locations, the duplicated rps19 was detected in C. fuscus, C. glomeratus, and C. difformis
Three genes, ndhG, ndhE, and ndhF, showed the same distance to JSB and JSA in C. fuscus, C. glomeratus, and C. difformis, which differed from those of C. esculentus and C. rotundus. These results indicated that C. esculentus and C. rotundus are more similar in genomic structure, whereas C. fuscus, C. glomeratus, and C. difformis are closely related

Summary

Introduction

Cyperus esculentus L., known as yellow tigernut, yellow nutsedge, or chufa, is a perennial C4 plant in the sedge family (Cyperaceae), which is comprised of approximately species worldwide. It occurs as wild or cultivated varieties and exhibits ecological plasticity and a wide global distribution [1]. In contrast to oil-bearing crops that mainly produce oil in seeds as well as the mesocarp of certain fruits, C. esculentus might be the only plant known that accumulates a large amount of oil as one of the main storage reserves in its underground tubers [2]. The unique characteristics of the species make it a promising resource for producing edible oil and biofuel in the food and chemical industries, and provide a novel model system for studying oil accumulation in non-seed tissues [3]

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Results

Conclusion