Genomic background selection to reduce the mutation load after random mutagenesis

Nirosha L Karunarathna,Niharika Sashidhar,Christian Jung,Dilan S R Patiranage,Hans-Joachim Harloff

doi:10.1038/s41598-021-98934-5

Nirosha L Karunarathna, Niharika Sashidhar + Show 3 more

Open Access

https://doi.org/10.1038/s41598-021-98934-5

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Abstract

Random mutagenesis is a standard procedure to increase allelic variation in a crop species, especially in countries where the use of genetically modified crops is limited due to legal constraints. The chemical mutagen EMS is used in many species to induce random mutations throughout the genome with high mutation density. The major drawback for functional analysis is a high background mutation load in a single plant that must be eliminated by subsequent backcrossing, a time and resource-intensive activity. Here, we demonstrate that genomic background selection combined with marker-assisted selection is an efficient way to select individuals with reduced background mutations within a short period. We identified BC1 plants with a significantly higher share of the recurrent parent genome, thus saving one backcross generation. Furthermore, spring rapeseed as the recurrent parent in a backcrossing program could accelerate breeding by reducing the generation cycle. Our study depicts the potential for reducing the background mutation load while accelerating the generation cycle in EMS-induced winter oilseed rape populations by integrating genomic background selection.

Highlights

To accelerate breeding, breeders use different methods like single seed descent (SSD) in pedigree breeding and doubled haploid (DH) technology[15]
This study demonstrates that plants with substantially lower mutation load can be selected from the first backcross generation
This study demonstrates the potential of genomic background selection for introducing EMS-induced alleles into oilseed rape breeding lines with a fast reduction of background mutation load

Summary

Introduction

Breeders use different methods like single seed descent (SSD) in pedigree breeding and doubled haploid (DH) technology[15]. A recent study claimed to accelerate crop research and breeding by "speed breeding"[2] Among other species, they grew canola (B. napus) under prolonged photoperiods with a day length of 22 h in a temperature-controlled glasshouse fitted with high-pressure sodium lamps. They grew canola (B. napus) under prolonged photoperiods with a day length of 22 h in a temperature-controlled glasshouse fitted with high-pressure sodium lamps Under these controlled-environmental conditions, they reduced generation cycles for spring canola to 73 ± 9 days[2]. Genomic background selection retains the original characters of the recurrent parent, reducing the number of generation cycles needed to obtain an improved elite line[16,17]. This study demonstrates that plants with substantially lower mutation load can be selected from the first backcross generation. The application for breeding with EMS mutagenized plants is discussed

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