A transcriptomic view of the ability of nascent hexaploid wheat to tolerate aneuploidy

Deying Zeng,Youliang Zheng,Aili Li,Laibin Zhao,Dengcai Liu,Lianquan Zhang,Long Mao,Jiantao Guan,Jiangtao Luo,Shunzong Ning,Wenshuai Chen,Yazhou Li,Zhongwei Yuan,Ming Hao

doi:10.1186/s12870-020-2309-6

Abstract

BackgroundIn contrast to most animal species, polyploid plant species are quite tolerant of aneuploidy. Here, the global transcriptome of four aneuploid derivatives of a synthetic hexaploid wheat line was acquired, with the goal of characterizing the relationship between gene copy number and transcript abundance.ResultsFor most of the genes mapped to the chromosome involved in aneuploidy, the abundance of transcripts reflected the gene copy number. Aneuploidy had a greater effect on the strength of transcription of genes mapped to the chromosome present in a noneuploid dose than on that of genes mapped elsewhere in the genome. Overall, changing the copy number of one member of a homeologous set had little effect on the abundance of transcripts generated from the set of homeologs as a whole, consistent with the tolerance of aneuploidy exhibited by allopolyploids, whether in the form of a chromosomal deficit (monosomy) or chromosomal excess (trisomy).ConclusionsOur findings shed new light on the genetic regulation of homeoallele transcription and contribute to a deeper understanding of allopolyploid genome evolution, with implications for the breeding of polyploid crops.

Highlights

In contrast to most animal species, polyploid plant species are quite tolerant of aneuploidy
The aneuploids isolated among the progeny of the hybrid AS313 x AS60 allohexaploid comprised the following (Fig. 1): a 2n = 41 plant lacking one copy of chromosome 4B (M4B), a 2n = 43 plant trisomic for chromosome 4B (Tri4B), a 2n = 42 plant harbouring four copies of a segment of chromosome arm 2AS (SegT2A)
Spike imaged at the heading stage, illustrating the nature of the samples taken for RNA extraction and a 2n = 40 plant lacking both copies of chromosome

Summary

Introduction

In contrast to most animal species, polyploid plant species are quite tolerant of aneuploidy. Aneuploidy is tolerated by many plant species; it has been almost a century since a full set of Datura stramonium trisomies was isolated [4]. Polyploid species, which are very common in the plant kingdom but rare in the animal kingdom, are tolerant of aneuploidy. Perhaps the best studied example of this phenomenon is presented by the hexaploid species Triticum aestivum (bread wheat), for which Sears [5] was able to derive an almost complete set of nullisomic, monosomic, trisomic, tetrasomic and ditelosomic variants based on the discovery of monosomic and trisomic plants among the offspring of two haploid progeny of a Chinese Spring (CS)

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