Chromosomes 1BS and 1RS for control of male fertility in wheats and triticales with cytoplasms of Aegilops kotschyi, Ae. mutica and Ae. uniaristata

Abstract

Engineered chromosomes 1BS and 1RS offer a new alternative in the development of hybrid systems in bread wheat and triticale. In the cytoplasmic male sterility system for hybrid wheat based on the cytoplasm of Triticum timopheevi fertility restoration is difficult, with few good restorer genes available. In the system based on the cytoplasms of Aegilops kotschyi, Ae. uniaristata and Ae. mutica, essentially all chromosomes 1B carry locus Rf that restores male fertility; male sterility manifests itself in wheats with the 1RS.1BL translocation where 1BS chromosome arm is missing. To generate male sterile wheats without the 1RS.1BL translocation, the 1BS arm was cytogenetically engineered to replace the segment with Rf with two short inserts of rye chromatin. Conversely, to enhance fertility restoration by doubling the number of restorers present for eventual use in wheat and triticale, a region of 1BS with Rf was inserted into 1RS. Alloplasmic wheats with Rf removed were completely male sterile; alloplasmic wheats with engineered 1RS carrying Rf and without normal 1B were male fertile. An exception to the ubiquitous presence of Rf is T. spelta var. duhamelianum; four accessions tested in this study gave inconsistent results but some did not restore male fertility. Engineered chromosomes 1BS and 1RS and chromosomes 1B of T. spelta offer a new alternative for practical application of a cytoplasmic male sterility system in the development of hybrid wheat and hexaploid triticale.

Chromosome-scale genome assembly provides insights into rye biology, evolution, and agronomic potential

“…mutica Bois. 58 can be efficiently restored by the wheat locus Rf multi ( Restoration-of-fertility in multiple CMS systems ) on chromosome 1BS. Replacement of the Rf multi locus by its rye ortholog produces the male-sterile phenotype 59,60 .…”

“…Thus, the absence of a TraesCS1B02G071642.1 ortholog in the non-restorer rye suggests it as an attractive Rf multi candidate. The only current implementations of a wheat- rye Rf multi CMS system involve 1RS.1BL translocations 5,58,61 , which are typically linked to reduced baking quality 40 . Breaking this linkage may now benefit from marker development and/or genome editing approaches targeting TraesCS1B02G071642.1 .…”

Chromosome manipulations for progress of triticale (×Triticosecale) breeding

“…Apart from the cytoplasm of T. timopheevi , there are several other cytoplasms that also create male sterility in wheat and triticale, mainly from Aegilops species. Lukaszewski () has reported that alloplasmic lines of triticale cv. ‘Presto’ with cytoplasms of Aegilops kotschyi , Aegilops uniaristata , and Aegilops mutica carrying 1D (1B) chromosome substitution are male sterile and that unlike the timopheevi cytoplasm (Curtis & Lukaszewski, ), rye chromosomes of cv.…”

Differential and interactive effects of cytoplasmic substitution and seed ageing on submergence stress response in wheat (Triticum aestivum L.)

“…In wheat, several studies demonstrated positive and negative effects on disease resistance [3,4], photosynthesis and respiration [5], plant height and heading date [6], yield potential [7], seed quality [8], alterations in transcriptomes and metabolomes [9] as well as abiotic stress tolerance [10,11]. However, practical utilization of cytoplasmic diversity and NC interaction in agriculture remains largely unexplored except for well-studied cytoplasmic male sterility and nuclear restoration of fertility for hybrid wheat production [12][13][14][15].…”