Pm55, a developmental-stage and tissue-specific powdery mildew resistance gene introgressed from Dasypyrum villosum into common wheat

Abstract

Powdery mildew resistance gene Pm55 was physically mapped to chromosome arm 5VS FL 0.60-0.80 of Dasypyrum villosum . Pm55 is present in T5VS·5AL and T5VS·5DL translocations, which should be valuable resources for wheat improvement. Powdery mildew caused by Blumeria graminis f. sp. tritici is a major wheat disease worldwide. Exploiting novel genes effective against powdery mildew from wild relatives of wheat is a promising strategy for controlling this disease. To identify novel resistance genes for powdery mildew from Dasypyrum villosum, a wild wheat relative, we evaluated a set of Chinese Spring-D. villosum disomic addition and whole-arm translocation lines for reactions to powdery mildew. Based on the evaluation data, we concluded that the D. villosum chromosome 5V controls post-seedling resistance to powdery mildew. Subsequently, three introgression lines were developed and confirmed by molecular and cytogenetic analysis following ionizing radiation of the pollen of a Chinese Spring-D. villosum 5V disomic addition line. A homozygous T5VS·5AL translocation line (NAU421) with good plant vigor and full fertility was further characterized using sequential genomic in situ hybridization, C-banding, and EST-STS marker analysis. A dominant gene permanently named Pm55 was located in chromosome bin 5VS 0.60-0.80 based on the responses to powdery mildew of all wheat-D. villosum 5V introgression lines evaluated at both seeding and adult stages. This study demonstrated that Pm55 conferred growth-stage and tissue-specific dependent resistance; therefore, it provides a novel resistance type for powdery mildew. The T5VS·5AL translocation line with additional softness loci Dina/Dinb of D. villosum provides a possibility of extending the range of grain textures to a super-soft category. Accordingly, this stock is a new source of resistance to powdery mildew and may be useful in both resistance mechanism studies and soft wheat improvement.

Molecular Characterization of the Dwarf53 Gene Homolog in Dasypyrum Villosum

“…Pm21 and PmV powdery mildew resistance genes introduced from D. villosum into common wheat as parts of T6V#2S·6AL and T6V#4S·6DL translocations have already been successfully used in the development of many commercial varieties [15]. Additionally, Dasypyrum was used in wheat breeding as a source of wheat streak mosaic virus resistance genes [16], Pm62 powdery mildew resistance genes as part of the T2BS.2VL#5 translocation [17], the Pm55 gene [18] and the Sr52 stem rust resistance gene, which is effective against the Ug99 race [19]. The alien genetic material of Dasypyrum can also contribute to improving the yield and quality of wheat grains [20,21].…”

Characterization and Evaluation of Resistance to Powdery Mildew of Wheat–Aegilops geniculata Roth 7Mg (7A) Alien Disomic Substitution Line W16998

“…Many powdery mildew resistance genes are derived from wild relatives of wheat, and have been introduced to common wheat by additions, substitutions, and translocations of chromosomes. For example, Pm21 and Pm55 are derived from Haynaldia villosa Schur [6,7], and Pm40 is derived from Elytrigia intermedia (Host) Nevski [8]. Pm12, Pm32, and Pm53 are derived from Aegilops speltoides Tausch [9][10][11].…”

Evaluation of resistance to powdery mildew and identification of resistance genes in wheat cultivars

“…Powdery mildew, caused by the biotrophic fungus Blumeria graminis f. sp. tritici (Bgt), is one of the most serious diseases limiting wheat production in many regions of the world [3].…”