Molecular mapping of leaf rust resistance gene LrNJ97 in Chinese wheat line Neijiang 977671

Abstract

Neijiang 977671 and 19 near-isogenic lines with known leaf rust resistance genes were inoculated with 12 pathotypes of Puccinia triticina for postulation of leaf rust resistance genes effective at the seedling stage. The reaction pattern of Neijiang 977671 differed from those of the lines with known leaf rust resistance genes used in the test, indicating that Neijiang 977671 may carry a new leaf rust resistance gene(s). With the objective of identifying and mapping the new gene for resistance to leaf rust, F1 and F2 plants, and F2:3 families, from Neijiang 977671 × Zhengzhou 5389 (susceptible) were inoculated with Chinese P. triticina pathotype FHNQ in the greenhouse. Results from the F2 and F2:3 populations indicated that a single dominant gene, temporarily designated LrNJ97, conferred resistance. In order to identify other possible genes in Neijiang 977671 other eight P. triticina pathotypes avirulent on Neijiang 977671 were used to inoculate 25 F2:3 families. The results showed that at least three leaf rust resistance genes were deduced in Neijiang 977671. Bulked segregant analysis was performed on equal amounts of genomic DNA from 20 resistant and 20 susceptible F2 plants. SSR markers polymorphic between the resistant and susceptible bulks were used to analyze the F2:3 families. LrNJ97 was linked to five SSR loci on chromosome 2BL. The two closest flanking SSR loci were Xwmc317 and Xbarc159 at genetic distances of 4.2 and 2.2 cM, respectively. At present two designated genes (Lr50 and Lr58) are located on chromosome 2BL. In the seedling tests, the reaction pattern of LrNJ97 was different from that of Lr50. Lr50 and Lr58 were derived from T. armeniacum and Ae. triuncialis, respectively, whereas according to the pedigree of Neijiang 977671 LrNJ97 is from common wheat. Although seeds of lines with Lr58 were not available, it was concluded that LrNJ97 is likely to be a new leaf rust resistance gene.

QTL Mapping of Adult-Plant Resistance to Leaf Rust in the Wheat Cross Zhou 8425B/Chinese Spring Using High-Density SNP Markers

“…Leaf rust (LR), caused by Puccinia triticina ( Pt ), is an important disease on wheat. LR occurred severely in 1969, 1973, 1975, 1979, and 2012 in China and caused serious yield loss (Dong, 2001; Zhou et al, 2013). Although LR can be controlled by fungicides overuse may lead to fungicide residues in the grain, or resistance to fungicides followed by a resurgence of the disease under favorable conditions (Luo, 2009).…”

Genetic analysis and molecular mapping of a leaf rust resistance gene in the wheat line 19HRWSN-129

“…Since the seedling resistance might be easily lost due to newly emerged leaf rust virulent races, e.g. LrZH84 and LrNJ97 (Zhao et al 2008;Zhou et al 2013), the wheat line 19HRWSN-129 seems to be a novel resource for wheat leaf rust resistance breeding. We have temporarily designated the single dominant gene that confers seedling resistance in the wheat line 19HRWSN-129 as Lrshi.…”

Identification of a leaf rust resistance gene in the Chinese wheat line LB0288

“…Currently, SSR markers have been successfully used in important wheat traits such as resistance to stripe rust and powdery mildew resistance gene mapping research (Jarve et al 2000;Liu et al 2002). In our laboratory, many leaf rust resistance genes such as LrZH84 (Zhao et al 2008), LrG98 (Chen et al 2010), LrXi (Li et al 2010a), LrBi16 (Zhang et al 2011), LrNJ97 (Zhou et al 2013), and LrFun (Xing et al 2014) were identified using SSR markers.…”

“…In China leaf rust (LR) is traditionally important only in the southwest and northeast regions; but with increased planting densities and changing management practices it has become increasingly important in most of the major wheat producing areas. Destructive epidemics of LR occurred in 1969LR occurred in , 1973LR occurred in , 1975LR occurred in and 1979 in China (Dong 2001) and the yield losses were incurred in some regions of Gansu, Sichuan, Shaanxi, Henan and Anhui provinces in 2012 (Zhou et al 2013). Although fungicides can control the disease, the most effective, economic and environmentally safe way to control the disease is growing rust resistant cultivars.…”