Maize Genic Male-Sterility Genes and Their Applications in Hybrid Breeding: Progress and Perspectives

Abstract

As one of the most important crops, maize not only has been a source of the food, feed, and industrial feedstock for biofuel and bioproducts, but also became a model plant system for addressing fundamental questions in genetics. Male sterility is a very useful trait for hybrid vigor utilization and hybrid seed production. The identification and characterization of genic male-sterility (GMS) genes in maize and other plants have deepened our understanding of the molecular mechanisms controlling anther and pollen development, and enabled the development and efficient use of many biotechnology-based male-sterility (BMS) systems for crop hybrid breeding. In this review, we summarize main advances on the identification and characterization of GMS genes in maize, and construct a putative regulatory network controlling maize anther and pollen development by comparative genomic analysis of GMS genes in maize, Arabidopsis, and rice. Furthermore, we discuss and appraise the features of more than a dozen BMS systems for propagating male-sterile lines and producing hybrid seeds in maize and other plants. Finally, we provide our perspectives on the studies of GMS genes and the development of novel BMS systems in maize and other plants. The continuous exploration of GMS genes and BMS systems will enhance our understanding of molecular regulatory networks controlling male fertility and greatly facilitate hybrid vigor utilization in breeding and field production of maize and other crops.

Identification of genes involved in male sterility in wheat (Triticum aestivum L.) which could be used in a genic hybrid breeding system

“…Scheme to produce a maintainer line using a genic male sterility gene to force outcrossing. Figure adapted from Wan et al, . The system would also use other marker genes to prevent the release of the functional copy of the male sterility gene, and the selection for a heterozygote maintainer…”

“…However, its use in a commercial wheat hybrid system is of limited interest due to it having a "dominance" effect: This is why, when it became available, CRISPR-mediated mutation was used in the second phase of our work. A workable model has been proposed by Wan et al (2019) and has been slightly modified for this work highlighting the role of a genic male-sterile system in wheat ( Figure 5).…”

“…Scheme to produce a maintainer line using a genic male sterility gene to force outcrossing. Figure adapted fromWan et al, 2019. The system would also use other marker genes to prevent the release of the functional copy of the male sterility gene, and the selection for a heterozygote maintainerProducing a maintainer-line mf/mf Male-sterile line Mf:PD:SCG:HT Male-fertility (CalS or RPG1), pollen death gene (PD), Seed Coat Gene (SCG), and herbicide tolerance (HT) genes (in one transgene construct) transformed into a male-sterile plant mf/mf Mf:PD:SCG:HT/_:_:_:_ Male-fertility recovered in the previously male-sterile line.…”

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

“…Cross‐pollination of a hemizygous maintainer (ms/ms, Maintainer/−) to the male‐sterile line (ms/ms, −/−) would generate either a pure male‐sterile line (pollen‐lethality maintainer) or 50% of male‐sterile seeds and 50% of maintainer seeds (seed‐colour maintainers). Such transgenic maintainers have been recently constructed for utilizing nuclear male sterility to produce hybrids in maize and rice (Chang et al , ; Wu et al , ; Kim and Zhang, ; Zhang et al , ; Wan et al , ). Based on these ideas, we devised a tomato seedling‐colour maintainer by transforming the fertility‐restoration gene linked with the tomato ANT1 gene into the male‐sterile plant (Mathews et al , ).…”

Risks of Pollen-Mediated Gene Flow From Genetically Modified Maize During Co-Cultivation With Usual Maize Varieties

“…Несмотря на то, что трехгенная гибридная система на основе ЦМС использовалась в коммерческом производстве гибридных семян ГМ-кукурузы, ее широкому применению помешали серьезные проблемы (84). Большинство разработанных стратегий ЦМС не были успешно применены из-за отсутствия рентабельной, экологичной и генетически стабильной стратегии крупномасштабного размножения родительских линий с ЦМС (84). Мы не обнаружили в доступной литературе данных о широкомасштабной продаже и выращивании семян ГМ-кукурузы с ЦМС, хотя в 2017 году вышло сообщение о коммерческом выращивании ГМ-рапса с ЦМС (2).…”