Incomplete genome doubling enables to consistently enhance plant growth for maximum biomass production by altering multiple transcript co-expression networks in potato.

Kanglu Zhao,Yanting Wang,Liangcai Peng,Shang-Wen Tang,Jinxuan Wang,Meysam Madadi,Nengzhou Jin,Zhiyong Xiong,Lei Wu,Youmei Wang,Zhijun Xu,Jing Dong

doi:10.1007/s00122-021-03976-y

Abstract

Cytochimera potato plants, which mixed with diploid and tetraploid cells, could cause the highest and significantly increased biomass yield than the polyploid and diploid potato plants. Polyploidization is an important approach in crop breeding for agronomic trait improvement, especially for biomass production. Cytochimera contains two or more mixed cells with different levels of ploidy, which is considered a failure in whole genome duplication. Using colchicine treatment with diploid (Dip) potato (Solanum chacoense) plantlets, this study generated tetraploid (Tet) and cytochimera (Cyt) lines, which, respectively, contained complete and partial cells with genome duplication. Compared to the Dip potato, we observed remarkably enhanced plant growth and biomass yields in Tet and Cyt lines. Notably, the Cyt potato straw, which was generated from incomplete genome doubling, was of significantly higher biomass yield than that of the Tet with a distinctively altered cell wall composition. Meanwhile, we observed that one layer of the tetraploid cells (about 30%) in Cyt plants was sufficient to trigger a gene expression pattern similar to that of Tet, suggesting that the biomass dominance of Cyt may be related to the proportion of different ploidy cells. Further genome-wide analyses of co-expression networks indicated that down-regulation (against Dip) of spliceosomal-related transcripts might lead to differential alternative splicing for specifically improved agronomic traits such as plant growth, biomass yield, and lignocellulose composition in Tet and Cyt plants. In addition, this work examined that the genome of Cyt line was relatively stable after years of asexual reproduction. Hence, this study has demonstrated that incomplete genome doubling is a promising strategy to maximize biomass production in potatoes and beyond.

Highlights

Polyploidization is a basic feature of plant evolution and diversification via genome duplication (Wendel 2000), and polyploid plants often exhibit increment of organs, buffering of deleterious mutations, increased heterozygosity, and growth vigor (Cai et al 2007; Corneillie et al 2019; Shelley et al 2018)
Further genome-wide analyses of co-expression networks indicated that down-regulation of spliceosomal-related transcripts might lead to differential alternative splicing for improved agronomic traits such as plant growth, biomass yield and lignocellulose composition in Tet and Cyt plants
We found that the Tet-1 plant had a complete 48 chromosomes including two pairs of chromosomes 1, 2, and 3 each, while the Cyt-1 plant contained both diploid cells with parental Dip karyotype and tetraploid cells with Tet-1 like karyotype (Fig. 1a)

Summary

Introduction

Polyploidization is a basic feature of plant evolution and diversification via genome duplication (Wendel 2000), and polyploid plants often exhibit increment of organs, buffering of deleterious mutations, increased heterozygosity, and growth vigor (Cai et al 2007; Corneillie et al 2019; Shelley et al 2018). Regarding such features, polyploidization provides an effective non-transgenic breeding approach to increase grain and biomass yields in crops (Cai et al 2007; Corneillie et al 2019; Shelley et al 2018).

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Results

Conclusion