Transcriptomics, chromosome engineering and mapping identify a restorer-of-fertility region in the CMS wheat system msH1
An original RNA-seq mapping strategy, validated with chromosome engineering and physical mapping, identifies candidate genes for fertility restoration in the 6HchS chromosome of Hordeum chilense in the wheat msH1 system.
Cytoplasmic male sterility (CMS) is a valuable trait for hybrid seed production. The msH1 CMS system in common wheat results from the incompatibility between the nuclear genome of wheat and the cytoplasm of the wild barley Hordeum chilense. This work aims to identify H. chilense candidate genes for fertility restoration in the msH1 system with a multidisciplinary strategy based on chromosome engineering, differential expression analysis and genome mapping. Alloplasmic isogenic wheat lines differing for fertility, associated with the presence of an acrocentric chromosome Hchac resulting from the rearrangement of the short arms of H. chilense chromosomes 1Hch and 6Hch, were used for transcriptome sequencing. Two novel RNA-seq mapping approaches were designed and compared to identify differentially expressed genes of H. chilense associated with male fertility restoration. Minichromosomes (Hchmi), new smaller reorganizations of the Hchac also restoring fertility, were obtained and used to validate the candidate genes. This strategy was successful identifying a putative restorer-of-fertility region on 6HchS, with six candidate genes, including the ortholog of the barley restorer gene Rfm1. Additionally, transcriptomics gave preliminary insights on sterility and restoration networks showing the importance of energy supply, stress, protein metabolism and RNA processing.
KeywordsCytoplasmic male sterility Common wheat Hordeum chilense Minichromosomes Restorer-of-fertility RNA-seq
This research was funded by Grants AGL2013-43329-R and SOLAUT_00025062, from Ministerio de Economía y Competitividad, Spain (MINECO).
Author Contribution statement
AC, AM, CR-S and FP conceived and planned the experiments. AC and CR collected the plant material. PB performed the bioinformatic analysis. CR-S and PB analyzed RNA-seq results. CR-S performed primer design, mapping and results interpretation. ACM, AM, CR and CR-S participated in minichromosomes obtaining. ACR performed GISH. CR-S wrote the manuscript in consultation with ACM, LC, PB and SGA. All authors gave critical feedback.
Compliance with ethical standards
Conflict of interest
On behalf of all authors, the corresponding author states that there is no conflict of interest.
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