Quantitative trait loci and candidate genes associated with freezing tolerance of winter triticale (× Triticosecale Wittmack)

Abstract

Freezing tolerance of triticale is a major trait contributing to its winter hardiness. The identification of genomic regions — quantitative trait loci (QTL) and molecular markers associated with freezing tolerance in winter hexaploid triticale — was the aim of this study. For that purpose, a new genetic linkage map was developed for the population of 92 doubled haploid lines derived from ‘Hewo’ × ‘Magnat’ F1 hybrid. Those lines, together with parents were subjected to freezing tolerance test three times during two winter seasons. Plants were grown and cold-hardened under natural fall/winter conditions and then subjected to freezing in controlled conditions. Freezing tolerance was assessed as the plants recovery (REC), the electrolyte leakage (EL) from leaves and chlorophyll fluorescence parameters (JIP) after freezing. Three consistent QTL for several fluorescence parameters, electrolyte leakage, and the percentage of the survived plants were identified with composite interval mapping (CIM) and single marker analysis (SMA). The first locus Qfr.hm-7A.1 explained 9% of variation of both electrolyte leakage and plants recovery after freezing. Two QTL explaining up to 12% of variation in plants recovery and shared by selected chlorophyll fluorescence parameters were found on 4R and 5R chromosomes. Finally, main locus Qchl.hm-5A.1 was detected for chlorophyll fluorescence parameters that explained up to 19.6% of phenotypic variation. The co-located QTL on chromosomes 7A.1, 4R and 5R, clearly indicated physiological and genetic relationship of the plant survival after freezing with the ability to maintain optimal photochemical activity of the photosystem II and preservation of the cell membranes integrity. The genes located in silico within the identified QTL include those encoding BTR1-like protein, transmembrane helix proteins like potassium channel, and phosphoric ester hydrolase involved in response to osmotic stress as well as proteins involved in the regulation of the gene expression, chloroplast RNA processing, and pyrimidine salvage pathway. Additionally, our results confirm that the JIP test is a valuable tool to evaluate freezing tolerance of triticale under unstable winter environments.

To Be or Not to Be? Are Reactive Oxygen Species, Antioxidants, and Stress Signalling Universal Determinants of Life or Death?

“…Stress is (6) multilevel. It has an impact at each level of the organism’s complexity: from molecular and physiological, through inter-organellar, intercellular, or inter-organs, to interactions between organisms (in the community) [ 8 , 9 ]. Considering the interaction between environmental factors and organisms, stress is (7) synchronous.…”

The Genome Regions Associated with Abiotic and Biotic Stress Tolerance, as Well as Other Important Breeding Traits in Triticale

“…The main advantage of a genetic map is that it can provide a useful resource for comparative genomics, the mapping of quantitative trait loci (QTL) associated with multiple important traits as well as linking physical and genetic maps, and consequently, detecting candidate genes associated with multiple proteins. High-density genetic maps have been described for many plants including crops such as wheat, rye, and barley but also, for triticale [ 15 , 16 , 18 , 19 , 20 , 21 , 22 , 23 ]. Most of those maps were developed using DArT (diversity arrays technology), DArT-seq (diversity arrays technology sequencing) and SNP (single-nucleotide polymorphism) marker systems, which are widely used in genetic map construction for multiple crop species.…”

“…This map was composed of 911 markers and assigned to 21 linkage groups with a total map length of 2837.3 cM. Subsequently, Wąsek et al [ 23 ] described a modified genetic map for the ‘Hewo’ × ‘Magnat’ DH population. This map was 1367.7 cM long and composed of 41 SSR and 680 DArT markers ordered into 22 linkage groups (the 7A, 2B, and 3B chromosomes were represented by double linkage groups).…”

“…The highest number of markers assigned to the A and B linkage group was found in the DH ‘Hewo’ × ‘Magnat’ line mapping population [ 21 ] while for the R group in the DH ‘Saka’ × ‘Modus’ line mapping population [ 20 ]. Additionally, the A group was previously described by Tyrka et al [ 20 , 21 ], Karbarz et al [ 22 ], Wąsek et al [ 23 ], and Dyda et al [ 16 ] as the one with the lowest number of markers assigned, regardless of the marker type used in the map construction.…”

Candidate Genes Underlying QTL for Powdery Mildew Resistance in Triticale (x Triticosecale Wittm.)

“…The percentage of phenotypic variation was calculated using a single-factor regression (R 2 ) and favorable allele was selected based on additive effects (Add) at LOD peaks obtained by Windows QTLCartographer 2.5. The candidate genes were in silico located within all identi ed QTL regions according to method described by Wąsek et al (2021).…”