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Genetic Diversity and Evolutionary Analyses Reveal the Powdery Mildew Resistance Gene Pm21 Undergoing Diversifying Selection.
Front Genet. 2020; 11:489.FG

Abstract

Wheat powdery mildew caused by Blumeria graminis f. sp. tritici (Bgt) is a devastating disease that threatens wheat production and yield worldwide. The powdery mildew resistance gene Pm21, originating from wheat wild relative Dasypyrum villosum, encodes a coiled-coil, nucleotide-binding site, leucine-rich repeat (CC-NBS-LRR) protein and confers broad-spectrum resistance to wheat powdery mildew. In the present study, we isolated 73 Pm21 alleles from different powdery mildew-resistant D. villosum accessions, among which, 38 alleles were non-redundant. Sequence analysis identified seven minor insertion-deletion (InDel) polymorphisms and 400 single nucleotide polymorphisms (SNPs) among the 38 non-redundant Pm21 alleles. The nucleotide diversity of the LRR domain was significantly higher than those of the CC and NB-ARC domains. Further evolutionary analysis indicated that the solvent-exposed LRR residues of Pm21 alleles had undergone diversifying selection (dN/dS = 3.19734). In addition, eight LRR motifs and four amino acid sites in the LRR domain were also experienced positive selection, indicating that these motifs and sites play critical roles in resistance specificity. The phylogenetic tree showed that 38 Pm21 alleles were divided into seven classes. Classes A (including original Pm21), B and C were the major classes, including 26 alleles (68.4%). We also identified three non-functional Pm21 alleles from four susceptible homozygous D. villosum lines (DvSus-1 to DvSus-4) and two susceptible wheat-D. villosum chromosome addition lines (DA6V#1 and DA6V#3). The genetic variations of non-functional Pm21 alleles involved point mutation, deletion and insertion, respectively. The results also showed that the non-functional Pm21 alleles in the two chromosome addition lines both came from the susceptible donors of D. villosum. This study gives a new insight into the evolutionary characteristics of Pm21 alleles and discusses how to sustainably utilize Pm21 in wheat production. This study also reveals the sequence variants and origins of non-functional Pm21 alleles in D. villosum populations.

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Authors+Show Affiliations

He H
School of Food and Biological Engineering, Jiangsu University, Zhenjiang, China.
Ji J
School of Food and Biological Engineering, Jiangsu University, Zhenjiang, China.
Li H
National Engineering Laboratory for Crop Molecular Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China.
Tong J
School of Food and Biological Engineering, Jiangsu University, Zhenjiang, China.
Feng Y
School of Food and Biological Engineering, Jiangsu University, Zhenjiang, China.
Wang X
Crop Research Institution, Shandong Academy of Agricultural Sciences, Jinan, China.
Han R
Crop Research Institution, Shandong Academy of Agricultural Sciences, Jinan, China.
Bie T
Yangzhou Academy of Agricultural Sciences, Yangzhou, China.
Liu C
Crop Research Institution, Shandong Academy of Agricultural Sciences, Jinan, China.
Zhu S
School of Food and Biological Engineering, Jiangsu University, Zhenjiang, China. School of Environment, Jiangsu University, Zhenjiang, China.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

32477413

Citation

He, Huagang, et al. "Genetic Diversity and Evolutionary Analyses Reveal the Powdery Mildew Resistance Gene Pm21 Undergoing Diversifying Selection." Frontiers in Genetics, vol. 11, 2020, p. 489.
He H, Ji J, Li H, et al. Genetic Diversity and Evolutionary Analyses Reveal the Powdery Mildew Resistance Gene Pm21 Undergoing Diversifying Selection. Front Genet. 2020;11:489.
He, H., Ji, J., Li, H., Tong, J., Feng, Y., Wang, X., Han, R., Bie, T., Liu, C., & Zhu, S. (2020). Genetic Diversity and Evolutionary Analyses Reveal the Powdery Mildew Resistance Gene Pm21 Undergoing Diversifying Selection. Frontiers in Genetics, 11, 489. https://doi.org/10.3389/fgene.2020.00489
He H, et al. Genetic Diversity and Evolutionary Analyses Reveal the Powdery Mildew Resistance Gene Pm21 Undergoing Diversifying Selection. Front Genet. 2020;11:489. PubMed PMID: 32477413.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Genetic Diversity and Evolutionary Analyses Reveal the Powdery Mildew Resistance Gene Pm21 Undergoing Diversifying Selection. AU - He,Huagang, AU - Ji,Jian, AU - Li,Hongjie, AU - Tong,Juan, AU - Feng,Yongqiang, AU - Wang,Xiaolu, AU - Han,Ran, AU - Bie,Tongde, AU - Liu,Cheng, AU - Zhu,Shanying, Y1 - 2020/05/12/ PY - 2020/03/17/received PY - 2020/04/20/accepted PY - 2020/6/2/entrez PY - 2020/6/2/pubmed PY - 2020/6/2/medline KW - Dasypyrum villosum KW - Pm21 allele KW - diversifying selection KW - evolutionary analysis KW - genetic diversity KW - wheat powdery mildew resistance SP - 489 EP - 489 JF - Frontiers in genetics JO - Front Genet VL - 11 N2 - Wheat powdery mildew caused by Blumeria graminis f. sp. tritici (Bgt) is a devastating disease that threatens wheat production and yield worldwide. The powdery mildew resistance gene Pm21, originating from wheat wild relative Dasypyrum villosum, encodes a coiled-coil, nucleotide-binding site, leucine-rich repeat (CC-NBS-LRR) protein and confers broad-spectrum resistance to wheat powdery mildew. In the present study, we isolated 73 Pm21 alleles from different powdery mildew-resistant D. villosum accessions, among which, 38 alleles were non-redundant. Sequence analysis identified seven minor insertion-deletion (InDel) polymorphisms and 400 single nucleotide polymorphisms (SNPs) among the 38 non-redundant Pm21 alleles. The nucleotide diversity of the LRR domain was significantly higher than those of the CC and NB-ARC domains. Further evolutionary analysis indicated that the solvent-exposed LRR residues of Pm21 alleles had undergone diversifying selection (dN/dS = 3.19734). In addition, eight LRR motifs and four amino acid sites in the LRR domain were also experienced positive selection, indicating that these motifs and sites play critical roles in resistance specificity. The phylogenetic tree showed that 38 Pm21 alleles were divided into seven classes. Classes A (including original Pm21), B and C were the major classes, including 26 alleles (68.4%). We also identified three non-functional Pm21 alleles from four susceptible homozygous D. villosum lines (DvSus-1 to DvSus-4) and two susceptible wheat-D. villosum chromosome addition lines (DA6V#1 and DA6V#3). The genetic variations of non-functional Pm21 alleles involved point mutation, deletion and insertion, respectively. The results also showed that the non-functional Pm21 alleles in the two chromosome addition lines both came from the susceptible donors of D. villosum. This study gives a new insight into the evolutionary characteristics of Pm21 alleles and discusses how to sustainably utilize Pm21 in wheat production. This study also reveals the sequence variants and origins of non-functional Pm21 alleles in D. villosum populations. SN - 1664-8021 UR - https://www.unboundmedicine.com/medline/citation/32477413/Genetic_Diversity_and_Evolutionary_Analyses_Reveal_the_Powdery_Mildew_Resistance_Gene_Pm21_Undergoing_Diversifying_Selection_ DB - PRIME DP - Unbound Medicine ER -