Evaluation of Genome Size, Chromosome Number and Karyotype in &amp;lt;i&amp;gt;Zygophyllum xanthoxylon&amp;lt;/i&amp;gt;

Yanbo Wu,Shengdan Wu,Linjing Zhang,Cui Liu,Yue Wang

doi:10.11648/j.eeb.20210602.11

Evaluation of Genome Size, Chromosome Number and Karyotype in &lt;i&gt;Zygophyllum xanthoxylon&lt;/i&gt;

Yanbo Wu, Shengdan Wu + Show 3 more

Open Access

https://doi.org/10.11648/j.eeb.20210602.11

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Abstract

Zygophyllum xanthoxylon, a super-xerophytic shrub in drylands, is widely used for afforestation in the arid and barren mountains of central Asia. Understanding the karyotype and genome size could provide basic information for genome sequencing of species. To date, few data on the DNA content and chromosomal characterization of Z. xanthoxylon have been reported. Here, we present both the karyotype analysis and genome size determination of Z. xanthoxylon based on the traditional pressing and flow cytometry methods. Chromosome counting showed that Z. xanthoxylon is diploid with a chromosome number of 22. Karyotype analysis revealed that the length of chromosomes ranges from 0.88 ± 0.08 μm to 2.36 ± 0.19 μm, the chromosomes are metacentric or submetacentric, and the karyotype formula is 2n = 2x = 22 = 18m + 4sm. Flow cytometry analysis estimated that the nuclear genome size of Z. xanthoxylon is 460 ± 7.05 Mbp. Interestingly, our results indicated the seedlings of Z. xanthoxylon exhibit endopolyploidy, which may confer better ecological adaptation. Collectively, the present study will provide an important cytological basis for the study of the origin, evolution and utilization of Z. xanthoxylon.

Highlights

Zygophyllum xanthoxylon is a super-xerophytic shrub with strong drought tolerance that occurs in deserts and steppe deserts
Z. xanthoxylon is one of the pioneer tree species used in barren mountain afforestation in arid areas and can play an important role in soil and water conservation
The results suggest that root tip cells of Z. xanthoxylon exhibit endopolyploidy (Figure 1)

Summary

Introduction

Zygophyllum xanthoxylon is a super-xerophytic shrub with strong drought tolerance that occurs in deserts and steppe deserts. Z. xanthoxylon is of great practical value in terms of environmental recovery and has economic benefits. Endopolyploidy is defined as the occurrence of different ploidy levels within an organism generated either by endoreduplication, which is predominant in plants, or by endomitosis, which mainly occurs in animals. Endoreduplication is attributed to the activities of topoisomerase II and topoisomerase VI during the mitotic cycle in plants [2]. This specific strategy of endoreduplication may be adopted to combat internal and/or external stresses, the increase in ploidy levels can influence gene expression, increases the content of secondary metabolites and enzymes, thereby increasing the adaptability of allopolyploidy [3]

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Conclusion