Molecular tagging of a new broad-spectrum powdery mildew resistance allele Pm2c in Chinese wheat landrace Niaomai

Abstract

A new broad-spectrum powdery mildew resistance allele Pm2c was identified and mapped in Chinese wheat landrace Niaomai. Chinese wheat landrace Niaomai showed resistance to 27 of 28 Chinese Blumeria graminis f. sp tritici (Bgt) races. Genetic analysis of an F2 population and its derived F2:3 families from the cross Niaomai × Mingxian 169 and backcross population, Niaomai/2*Mingxian 169, indicated that the resistance of Niaomai to Bgt races was conferred by a single dominant resistance gene, temporarily designated PmNM. Molecular tagging showed that PmNM was located on chromosome 5DS and flanked by SSR markers Xcfd81 and Xcfd78 with the genetic distances of 0.1/0.4 cM and 4.9/7.5 cM, respectively. Niaomai showed a different array of responses compared to lines with Pm2a, Pm2b, PmD57-5D, PmLX66, PmX3986-2 and Pm48 genes, sharing the same Xcfd81 allele but differing from Xcfd78 allele for Pm2a and Pm2b lines. Allelism tests based on crosses of Niaomai with Ulka/8*Cc and KM2939 showed that PmNM is allelic to Pm2a and Pm2b. We concluded that PmNM is a new allele of Pm2, re-designated Pm2c. Pm2c could be transferred into wheat cultivars by marker-assisted selection to improve the powdery mildew resistance of breeding cultivars/lines.

Mechanisms of powdery mildew resistance of wheat – a review of molecular breeding

“…Compared to distant relatives, landraces are ready for direct crossing of interesting traits into new cultivars. A set of wheat landraces have exhibited highly significant resistance to powdery mildew, formally designated as Pm2c (Xu et al , 2015), Pm3b (Yahiaoui et al , 2004), Pm5d (Hsam et al , 2001), Pm5e (Huang et al , 2003), Pm24a (Huang et al , 2000), Pm24b (Xue et al , 2012), Pm47 (Xiao et al , 2013), Pm59 (Tan et al , 2018), and Pm63 (Tan et al , 2019).…”

Pm223899, a new recessive powdery mildew resistance gene identified in Afghanistan landrace PI 223899

“…Wheat landraces are important resistance sources, and at least 18 powdery mildew resistance genes have been identified in landraces, including Pm2c on chromosome 5DS (Xu et al 2015), Pm3b on 1AS (Yahiaoui et al 2004), Pm5d and Pm5e on 7BL (Hsam et al 2001;Huang et al 2003), Pm24a…”

Characterization of the Powdery Mildew Resistance Gene in the Elite Wheat Cultivar Jimai 23 and Its Application in Marker-Assisted Selection

“…Powdery mildew caused by Blumeria graminis f. sp. tritici (Bgt) is one of the most damaging diseases, typically decreasing wheat yield by 10-15% and up to 50% in severe cases (Morgounov et al, 2012;Xu et al, 2015). In China alone, the area of winter wheat affected annually by powdery mildew has exceeded 6 m ha in recent decades, causing 300,000 tons of crop loss each year 1 .…”

“…The gene Pm8 derived from the 1RS chromosome of rye made a significant contribution to the control of wheat powdery mildew in 1990s, but the linked secalin glycopeptide in 1RS resulted in a decline in flour quality (Friebe et al, 1989;Lee et al, 1995). Additionally, the Pm genes derived from landraces usually have poor agronomic performance and need multigeneration backcrossing before acceptance by breeders (Xu et al, 2015;Li et al, 2020). Clearly, the value to breeding of a specific Pm gene depends not only on its effectiveness for disease control but also on the agronomic performance of its donor (Zhao et al, 2013;Ma et al, 2018).…”

“…Pm2b(Ma et al, 2015a), and Pm2c(Xu et al, 2015), have unclear genealogy and that several wheat cultivars having the Pm2 alleles, such as Liangxing 66 (genealogy: Ji91102/Jimai 19) with PmLX66 (Sun Y.L. et al, 2015), Wennong 14 (genealogy: 84139//9215/876161) with PmW14 (Sun Y.L.…”