Molecular Cytogenetic Identification of a New Wheat-Rye 6R Chromosome Disomic Addition Line with Powdery Mildew Resistance

Abstract

Rye (Secale cereale L.) possesses many valuable genes that can be used for improving disease resistance, yield and environment adaptation of wheat (Triticum aestivum L.). However, the documented resistance stocks derived from rye is faced severe challenge due to the variation of virulent isolates in the pathogen populations. Therefore, it is necessary to develop desirable germplasm and search for novel resistance gene sources against constantly accumulated variation of the virulent isolates. In the present study, a new wheat-rye line designated as WR49-1 was produced through distant hybridization and chromosome engineering protocols between common wheat cultivar Xiaoyan 6 and rye cultivar German White. Using sequential GISH (genomic in situ hybridization), mc-FISH (multicolor fluorescence in situ hybridization), mc-GISH (multicolor GISH) and EST (expressed sequence tag)-based marker analysis, WR49-1 was proved to be a new wheat-rye 6R disomic addition line. As expected, WR49-1 showed high levels of resistance to wheat powdery mildew (Blumeria graminis f. sp. tritici, Bgt) pathogens prevalent in China at the adult growth stage and 19 of 23 Bgt isolates tested at the seedling stage. According to its reaction pattern to different Bgt isolates, WR49-1 may possess new resistance gene(s) for powdery mildew, which differed from the documented powdery mildew gene, including Pm20 on chromosome arm 6RL of rye. Additionally, WR49-1 was cytologically stable, had improved agronomic characteristics and therefore could serve as an important bridge for wheat breeding and chromosome engineering.

Production and cytomolecular identification of new wheat-perennial rye (Secale cereanum) disomic addition lines with yellow rust resistance (6R) and increased arabinoxylan and protein content (1R, 4R, 6R)

“…Gallego and Benito (1997) found that Al tolerance is controlled by at least two major dominant and independent loci (Alt1 and Alt3) located on chromosomes 6RS and 4R. Powdery mildew resistance genes were also found on chromosomes 4R and 6R (Heun et al 1990;An et al 2013An et al , 2015.…”

Scale development and utilization of universal PCR-based and high-throughput KASP markers specific for chromosome arms of rye (Secale cereale L.)

“…Black diamond shapes indicate no template control in wheat breeding. A great number of desirable wheatrye progenies from various rye accession have been developed by distant hybridization and chromosome engineering, such as wheat-rye 6R disomic addition line WR49 carrying powdery mildew resistance derived from rye cultivar German White [37], wheat-rye 1R disomic addition line N9436B carrying powdery mildew resistance derived from rye cultivar Austrian [38], and wheatrye T1RS•1BL translocation lines from Chinese rye cultivar Baili with resistances to stripe rust and powdery mildew and desirable agronomic traits [39]. Compared with addition lines and substitution lines, translocation lines, especially small segment translocation lines carrying desirable traits, are preferred attributing to less linkage drag.…”

A 1Ns Disomic Addition from Psathyrostachys Huashanica Keng Confers Resistance to Powdery Mildew in Wheat

“…Thus, many studies have aimed to identify new resistance genes in the relatives of wheat [41,42]. In previous studies, the resistance genes Pm7, Pm8, Pm17, and Pm20 were identified in rye, and Pm8 was utilized widely, although the effectiveness of its resistance has now been lost [43][44][45]. Pm21, which is located on the short arm of chromosome 6V in Haynaldia villosa (2n = 14, VV) and it is an excellent gene that confers broad-spectrum resistance to powdery mildew in wheat [46].…”