Mapping QTL for resistance to eyespot of wheat in Aegilops longissima

Abstract

Eyespot is an economically important disease of wheat caused by the soilborne fungi Oculimacula yallundae and O. acuformis. These pathogens infect and colonize the stem base, which results in lodging of diseased plants and reduced grain yield. Disease resistant cultivars are the most desirable control method, but resistance genes are limited in the wheat gene pool. Some accessions of the wheat wild relative Aegilops longissima are resistant to eyespot, but nothing is known about the genetic control of resistance. A recombinant inbred line population was developed from the cross PI 542196 (R) × PI 330486 (S) to map the resistance genes and better understand resistance in Ae. longissima. A genetic linkage map of the S(l) genome was constructed with 169 wheat microsatellite markers covering 1261.3 cM in 7 groups. F(5) lines (189) were tested for reaction to O. yallundae and four QTL were detected in chromosomes 1S(l), 3S(l), 5S(l), and 7S(l). These QTL explained 44 % of the total phenotypic variation in reaction to eyespot based on GUS scores and 63 % for visual disease ratings. These results demonstrate that genetic control of O. yallundae resistance in Ae. longissima is polygenic. This is the first report of multiple QTL conferring resistance to eyespot in Ae. longissima. Markers cfd6, wmc597, wmc415, and cfd2 are tightly linked to Q.Pch.wsu-1S ( l ), Q.Pch.wsu-3S ( l ), Q.Pch.wsu-5S ( l ), and Q.Pch.wsu-7S ( l ), respectively. These markers may be useful in marker-assisted selection for transferring resistance genes to wheat to increase the effectiveness of resistance and broaden the genetic diversity of eyespot resistance.

Advances and Prospects in Wheat Eyespot Research: Contributions from Genetics and Molecular Tools

“…(1998) observed that resistance to the two pathogen species could be conferred by different genes. Similarly, Sheng and Murray (2009) observed that 20% of the A. longissima lines they tested responded differently to the two species, and Burt et al. (2010) identified four T. monococcum lines that responded differently to the two species.…”

“…intermedium (Li et al. 2004, 2005), and Aegilops longissima (Sheng and Murray 2009). Immune and highly resistant accessions were also identified in T. tauschii with a non‐transformed strain (Assefa and Fehrmann 1998).…”

“…Eyespot-resistant accessions were identified with a GUS-transformed strain of O. yallundae in Triticum tauschii (Yildirim et al 1995), T. monococcum (Cadle et al 1997), T. durum, T. dicoccoides and T. turanicum (Figliuolo et al 1998), Dasypyrum villosum (Yildirim et al 2000), Thinopyrum ponticum and Th. intermedium (Li et al 2004(Li et al , 2005, and Aegilops longissima (Sheng and Murray 2009). Immune and highly resistant accessions were also identified in T. tauschii with a non-transformed strain (Assefa and Fehrmann 1998).…”

Agronomically Relevant Traits Transferred to Major Crop Plants by Alien Introgressions

“…In T. monococcum, resistance for eyespot disease was found (Murray et al 1994 ), which was later transferred to the cultivated gene pool (Cadle et al 1997 ;Sheng et al 2012 ). Thus, in order to make use of the insect/pest resistance identifi ed in several different alien sources a large collection of synthetic wheat lines were developed at the International Maize and Wheat Improvement Center, CIMMYT, and are currently being used in several breeding programs around the globe (Mujeeb-Kazi and Rajaram 2002 ).…”

Identification of drought stress related proteins from 1Sl(1B) chromosome substitution line of wheat variety Chinese Spring

“…Aegilops species has attracted much attention since it has desirable gene resources and is widely used for wheat drought-resistance improvement (Zaharieva et al 2001; Molnár et al 2004). Particularly, Aegilops longissima (2n = 2x = 14, S l S l ) was shown to have eyespot and pre-harvest sprouting resistance (Sheng et al 2012; Singh et al 2013), and superior glutenin genes (Wang et al 2013). However, the gene resources for drought resistance in 1S l genome is not yet being explored and utilized so far.…”