Fine mapping of powdery mildew resistance gene PmTm4 in wheat using comparative genomics

Abstract

Powdery mildew, caused by Blumeria graminis f. sp. tritici, is one of the most severe wheat diseases. Mining powdery mildew resistance genes in wheat cultivars and their appliance in breeding program is a promising way to control this disease. Genetic analysis revealed that a single dominant resistance gene named PmTm4 originated from Chinese wheat line Tangmai 4 confers resistance to prevailing isolates of B. graminis f. sp. tritici isolate E09. Detailed comparative genomics analyses helped to develop closely linked markers to PmTm4 and a fine genetic map was constructed using large F 2 population, in which PmTm4 was located into a 0.66-cM genetic interval. The orthologous subgenome region of PmTm4 in Aegilops tauschii was identified, and two resistance gene analogs (RGA) were characterized from the corresponding sequence scaffolds of Ae. tauschii draft assembly. The closely linked markers and identified Ae. tauschii orthologs in the mapping interval provide an entry point for chromosome landing and map-based cloning of PmTm4.

The Pm5e Gene Has No Negative Effect on Wheat Agronomic Performance: Evidence From Newly Established Near-Isogenic Lines

“…Exceptions are cultivar Tangmai 4 and landrace Duanganmang with the dominant alleles. Sequence analysis confirms that both of them carry Pm5e ( Xie et al, 2017 , 2020 ; Wu et al, 2021 ). Genetic analysis of the powdery mildew resistance also revealed a dominant inheritance in line H962R, which also possesses Pm5e .…”

A rare single nucleotide variant in Pm5e confers powdery mildew resistance in common wheat

“…Pm5e is a NLR disease resistance gene, similar in structure and function to the other cloned wheat powdery mildew resistance genes Pm2 (Sanchez‐Martin et al ., 2016), Pm3 (Yahiaoui et al ., 2004), Pm8 (Hurni et al ., 2013), Pm17 (Singh et al ., 2018), Pm21 (He et al ., 2018; Xing et al ., 2018) and Pm60 (Zou et al ., 2018). However, unlike those other cloned genes that are dominant in their resistance function, Pm5e is largely regarded as a recessive or semi‐dominant powdery mildew resistance gene in FZ30 (Huang et al ., 2000, 2003), Hongquanmang (Zhou et al ., 2005), Tangmai 4 (Xie et al ., 2017), Mazhamai (Zhai et al ., 2008), Xiaobaidongmai (Jin et al ., 2020), Baiyouyantiao (Xu et al ., 2018) and other landraces carrying the Pm5e allele. Fuzhuang 30 ( Pm5e ) was highly resistant to Bgt isolate E20 with necrosis and no visible colonies (IT 0;) and Nongda 015 ( Pm5 ‐ ND ) was highly susceptible to the E20 Bgt isolate with a large number of visible colonies at 10 d post‐inoculation (IT 4) (Fig.…”

“…Interestingly, FZ30 has maintained its resistance to powdery mildew for over 80 yr (Zhuang, 2003). Pm5e and other alleles at the Pm5 locus, including Pm5d (CI 10904/PI 83395) (Hsam et al ., 2001), PmH (Hongquanmang) (Zhou et al ., 2005), Mlmz (Mazhamai) (Zhai et al ., 2008), Mlxbd (Xiaobaidongmai) (Jin et al ., 2020), PmTm4 (Tangmai 4) (Xie et al ., 2017) and PmBYYT (Baiyouyantiao) (Xu et al ., 2018), were genetically mapped to the distal region of chromosome arm 7BL. Thus, Pm5e and other alleles at the Pm5 locus represent a valuable source of powdery mildew resistance for wheat improvement, especially in China.…”

Fine mapping and gene cloning in the post-NGS era: advances and prospects

“…Using BSR-Seq, a set of 13-18 genes in syntenic cereal genomes for grain protein content (Trick et al 2012). Similarly, powdery mildew resistance gene PmTm4 was fine-mapped into 0.66 cM interval using comparative genomics approaches on large F 2 population (Xie et al 2017). Furthermore, high-density linkage mapping based on NGS-derived markers has enabled fine mapping of major traits like fungal resistance (Cockram et al 2015), powdery mildew resistance (Liang et al 2016), awn shape and length (Yoshioka et al 2017), flag leaf traits (Hussain et al 2017) and stripe rust resistance (Ma et al 2019).…”