Abstract:
Wheat (
Triticum aestivum L.) is an important crop in China, high and stable yields are crucial for ensuring food security. Powdery mildew caused by
Blumeria graminis f. sp.
tritici. (
Bgt)
is a devastating disease of wheat. Chemical and agricultural control methods are used to prevent powdery mildew, but utilizing host resistance may represent a more economical, environmentally friendly, and effective method to control the epidemic of powdery mildew. The powdery mildew resistance gene
Pm2, located on the short arm of chromosome 5D, encodes a CC-NBS-LRR protein and is one of the most widely used
Pm genes in wheat powdery mildew resistance breeding because of its excellent resistance and desirable agronomic traits. In this review, the recent progress in
Pm2 research and utilization in wheat breeding is systematically summarized in terms of the following aspects: identification and characterization of
Pm2, exploration and utilization of the alleles at the
Pm2 locus, gene cloning, development of functional markers, haplotype analysis,
AvrPm2 gene cloning, and the applications in wheat breeding programs. It has been proposed that: 1) the differences in the resistance of different
Pm2 alleles may be caused by diverse genetic backgrounds, other regulatory factors in the disease resistance pathway, or the highly heterozygous state of
Bgt isolates. 2) The powdery mildew resistance gene
Pm2 should be reasonably distributed and utilized in disease resistance breeding to prolong the service life of disease resistance genes and increase durability. 3) Essential methods to control the epidemic of powdery mildew should include mining and utilizing novel resistance genes and allelic variations and strengthening the innovation of new wheat germplasms. This review aimed to provide a theoretical basis for further work on the resistance mechanism of
Pm2 and to accelerate its application in wheat powdery mildew resistance breeding.
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