A biotechnology‐based male‐sterility system for hybrid seed production in tomato

Abstract

Incorporating male sterility into hybrid seed production reduces its cost and ensures high varietal purity. Despite these advantages, male-sterile lines have not been widely used to produce tomato (Solanum lycopersicum) hybrid seeds. We describe the development of a biotechnology-based breeding platform that utilized genic male sterility to produce hybrid seeds. In this platform, we generated a novel male-sterile tomato line by clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9)-mediated mutagenesis of a stamen-specific gene SlSTR1 and devised a transgenic maintainer by transforming male-sterile plants with a fertility-restoration gene linked to a seedling-colour gene. Offspring of crosses between a hemizygous maintainer and the homozygous male-sterile plant segregated into 50% non-transgenic male-sterile plants and 50% male-fertile maintainer plants, which could be easily distinguished by seedling colour. This system has great practical potential for hybrid seed breeding and production as it overcomes the problems intrinsic to other male-sterility systems and can be easily adapted for a range of tomato cultivars and diverse vegetable crops.

Induction of Male Sterility: A Boon for Plant Breeding

“…This, technique has been widely used to develop male sterile lines in different crops. A novel male-sterile line was developed by targeting stamen-specific gene SlSTR1 by CRISPR-Cas9 and developed a transgenic maintainer by transforming male-sterile plants with a fertility-restoration gene linked to a seedlingcolour gene in tomato (Du et al, 2020). Artificially synthesized Cas9 gene with biased codons targeted MS8 gene (Chen et al, 2018), and MS26 gene (Djukanovic et al, 2013) in maize to develop male sterile lines.…”

A Single Nucleotide Polymorphism in an R2R3 MYB Transcription Factor Triggers ms6 (Ames1) Male Sterility in Soybean

“…The 2nd one is a male gametophyte-killer gene, for killing the microspores carrying the transgenic component, so that only nontransgenic ms pollens are viable for hybrid production (Chang et al 2016;Song et al 2020). The 3rd one is a phenotypic reporter gene for monitoring the purity of obtained ms seeds, such as uorescence gene expressed in aleurone layer for monocots rice and maize (Chang et al 2016;Zhang et al 2018b) or anthocyanin synthesis gene expressed in early seedling stage for dicots tomato (Du et al 2020).…”

A novel strategy for creating a new system of third‐generation hybrid rice technology using a cytoplasmic sterility gene and a genic male‐sterile gene

“…Technological advances in the agricultural sector, especially plant breeding techniques, contributed to an increase in agricultural productivity (Du et al ., 2020; Gils et al ., 2008; Khan et al ., 2019; Ray et al ., 2007). In the last 50 years, remarkable growth in agricultural production has largely depended on cereal crops, especially rice, in China (Fan et al ., 2012).…”