Two Rye Genes Responsible for Abnormal Development of Wheat⁻Rye Hybrids Are Linked in the Vicinity of an Evolutionary Translocation on Chromosome 6R.

Natalia Tsvetkova,Anatoly Voylokov,Bernd Hackauf,Natalia Tikhenko

doi:10.3390/plants7030055

Abstract

The post-zygotic reproductive isolation (RI) in plants is frequently based on the negative interaction of the parental genes involved in plant development. Of special interest is the study of such types of interactions in crop plants, because of the importance of distant hybridization in plant breeding. This study is devoted to map rye genes that are incompatible with wheat, determining the development of the shoot apical meristem in wheat–rye hybrids. Linkage analysis of microsatellite loci, as well as genes of embryo lethality (Eml-R1) and hybrid dwarfness (Hdw-R1) was carried out in hybrids of Chinese Spring wheat with recombinant inbred lines as well as interline rye hybrids. Eml-R1 and Hdw-R1 could be mapped proximal and distal of two closely linked EST-SSR markers, Xgrm902 and Xgrm959, on rye chromosome 6R. Both rye genes are located on a segment of chromosome 6R that contains a breakpoint of evolutionary translocation between the ancestral chromosomes of homeologous groups 6 and 3. The obtained results are discussed in relation to genes interacting in developmental pathways as a class of causal genes of RI.

Highlights

Post-zygotic incompatibility in plants is often expressed in an autoimmune reaction and disturbances of plant development, leading to a decrease in the viability or death of hybrids
The loci Xgrm173 and Xgrm959–Xgrm902 carry different alleles in lines L6 and V1. This enabled testing the linkage of Hdw-R1 with these markers in a Chinese Spring (CS) × F1 (L6 × V1) cross
We describe for the first time that Eml-R1 is linked to another gene controlling post-zygotic reproductive isolation between wheat and rye, Hdw-R1

Summary

Introduction

Post-zygotic incompatibility in plants is often expressed in an autoimmune reaction (tissue necrosis) and disturbances of plant development, leading to a decrease in the viability or death of hybrids. Immunity and ontogenesis are controlled by many interacting genes. The interaction of genes is the basis of the canonical scheme (Bateson–Dobzhansky–Muller model), explaining the emergence and functioning of post-zygotic incompatibility. In cultivated and wild plants, a large number of genes controlling hybrid incompatibility in accordance with the classic two-locus scheme have been described [1]. The complementary interaction of incompatible alleles is established in interspecific and intraspecific hybrids. Phenotypes associated with hybrid necrosis resemble those elicited in response to various abiotic and biotic stresses [2]. While substantial progress has been achieved to uncover the molecular mechanisms by which disease resistance is achieved [2], the Plants 2018, 7, 55; doi:10.3390/plants7030055 www.mdpi.com/journal/plants

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