High-Resolution Melting-Based Marker Development for Wheat Leaf Rust Resistance Gene Lr34

Abstract

Deploying adult plant resistance (APR) against rust diseases is an important breeding objective of most wheat breeding programs. The gene Lr34 is an effective and widely deployed broad spectrum APR gene in wheat against leaf rust fungus Puccinia triticina. Various molecular markers have been developed for Lr34 but, either they require post-PCR handling processes or are not economical. Herein, we developed a high resolution melting (HRM) based diagnostic assay for Lr34 based on a three bp ‘TTC’ deletion in exon 11 of the resistant allele. The susceptible cv. Thatcher (Tc) and the near-isogenic Thatcher line (RL6058) with Lr34, yielded distinct melting profiles and were differentiated with high reproducibility. For further validation, all three copies of Lr34 were cloned in plasmid vectors and HRM analysis using individual and combination (equimolar mixture of three copies) of homoeologs yielded distinguishing melting profiles. An additional layer of genotyping was provided by a LunaProbe assay. The allele-specific probes successfully distinguished the homoeologs but not Tc and RL6058. Further, the practical deployment of the HRM assay was tested by running the marker on a set of breeding lines. When compared with a kompetitive allele-specific PCR (KASP) Lr34 assay, the HRM assay had similar genotyping results and was able to accurately differentiate the resistant and susceptible breeding lines. However, our HRM assay was unable to detect the heterozygote. To our knowledge, this is the first report of an HRM assay for genotyping a wheat rust resistance gene.

Identification and Analysis of Candidate Genes Associated with Yield Structure Traits and Maize Yield Using Next-Generation Sequencing Technology

“…The fifth significant SNP (29294) was located on chromosome 5 within the hydroxyproline o-galactosyltransferase galt6 gene. According to our analyses and data in the literature, this gene may be related to the yield of maize because, according to Kaur et al (2023), hydroxyproline o-galactosyltransferase galt6 plays an important role in various stages of plant growth and development [73]. Moreira et al (2023) have reported that arabinogalactan proteins (AGPs) are hydroxyproline-rich, sugar-rich glycoproteins widely distributed in the plant kingdom [74].…”

Quantitative Trait Loci Mapping for Adult-Plant Stripe Rust Resistance in Chinese Wheat Cultivar Weimai 8

“…Because of frequent changes in pathogen populations, cultivars conferring all-stage resistance genes lose stripe-rust resistance within a short period of time [13]. As a consequence, APR with apparent durability is increasingly being deployed in wheat-breeding and production programs [14][15][16][17].…”

Expression Profiling of the Slow Rusting Resistance Genes Lr34/Yr18 and Lr67/Yr46 in Common Wheat (Triticum aestivum L.) and Associated miRNAs Patterns

“…The gene has been cloned and two allelic variants have been distinguished in it: susceptible (Lr34sus) and resistant (Lr34res) [18,19]. These alleles differ in by 3-nucleotide indel resulting in a deletion of phenylalanine (Phe) at position 546 (exon 11) and a single nucleotide polymorphism (SNP) resulting in a tyrosine (Tyr) to histidine (His) substitution at position 634 (exon 12) in the Lr34Res protein [20,21]. Moreover, additional A/T SNP polymorphisms were discovered in intron 4 and a 1-nucleotide indel in exon 10 that causes a frameshift [18].…”