Rapid gene cloning in cereals

Abstract

The past two decades were characterized by a genomics revolution that entailed profound changes to crop research, plant breeding, and agriculture. Today, high-quality reference sequences are available for all major cereal crop species. Large re-sequencing and pan-genome projects start to reveal a more comprehensive picture of the genetic makeup and the diversity among domesticated cereals and their wild relatives. These technological advancements will have a dramatic effect on dissecting genotype-phenotype associations and on gene cloning. In this review, we will highlight the status of the genomic resources available for various cereal crops and we will discuss their implications for gene cloning. A particular focus will be given to the cereal species barley and wheat, which are characterized by very large and complex genomes that have been inaccessible to rapid gene cloning until recently. With the advancements in genomics and the development of several rapid gene cloning methods, it has now become feasible to tackle the cloning of most agriculturally important genes, even in wheat and barley. Key message The large and complex genomes of many cereals hindered cloning efforts in the past. Advances in genomics now allow the rapid cloning of genes from humanity's most valuable crops.

Breeding for Fusarium head blight resistance in wheat—Progress and challenges

“…From the perspective of the scientists, cloning and functional characterization of the underlying causal gene(s) is of utmost interest. Although substantial progress has been made in cloning genes, particularly major genes (Bettgenhaeuser & Krattinger, ) the complexity of the wheat genome in combination with the complexity of FHB resistance makes cloning of FHB resistance genes extremely challenging, as experienced by isolating Fhb1 (see above). Gene cloning will definitely profit from the fast progress in wheat genome sequencing with the first wheat reference sequence released in 2017, the resequencing project (He, Pasam, et al, ) and the establishment of a wheat pan‐genome (http://www.10wheatgenomes.com/).…”

High Resolution Genetic and Physical Mapping of a Major Powdery Mildew Resistance Locus in Barley

“…The structural analysis in both Rpm1 and Rpp5 clearly showed this variation was directly associated with the phenotype. To obtain the complete DNA sequence of the MlLa-H interval from the resistant parent, either developing high-quality de novo assembly from the flow-sorted barley mutant chromosome 2H or performing Targeted Locus Amplification (TLA) approach is highly recommended (de Vree et al, 2014; Thind et al, 2017; Bettgenhaeuser and Krattinger, 2018).…”

Wheat heat tolerance is impaired by heightened deletions in the distal end of 4AL chromosomal arm

“…Despite the progress outlined above, further efforts are still needed to better understand the genetic and molecular processes controlling wheat HST. To achieve this goal efficiently, it is desirable to isolate the genes that function directly in wheat HST by forward genetic analysis, which has proved to be highly effective in characterizing plant genes controlling important biological processes and agronomic traits (Bettgenhaeuser and Krattinger, 2019; Schneeberger and Weigel, 2011). However, it is challenging to isolate wheat genes controlling HST by positional cloning because heat response phenotypes are difficult to score, varying among genotypes and growth stages and requiring substantial inputs of time and labour (Li et al, 2019).…”