Validation of rice blast resistance genes in barley using a QTL mapping population and near-isolines

Abstract

There are prior reports of Pyricularia grisea-the causal agent of blast of rice-causing disease in barley. In order to determine the specificity of this resistance in barley, we extended our previous mapping efforts to include blast isolates from barley and rice grown in Thailand and we assessed two resistance phenotypes: leaf blast (LB) and neck blast (NB). The largest-effect resistance QTL, on chromosome 1H, was associated with NB and LB and is located in a region rich in resistance genes, including QTL conferring resistance to stripe rust (incited by Puccinia striiformis f. sp. hordei) and the mildew (Blumeria graminis f. sp. hordei) resistance gene Mla. The LB, NB and mildew resistance alleles trace to one parent (Baronesse) whereas the stripe rust resistance allele traces to the other parent (BCD47) of the mapping population. Baronesse is the susceptible recurrent parent of a set of near-isogenic lines (NILs) for three stripe rust resistance QTL, including one on 1H. Unigene (EST) derived single nucleotide polymorphism haplotypes of these NILs were aligned with the blast mapping population QTL using Mla as an anchor. Baronesse and all NILs without the 1H introgression were resistant to LB and NB. However, two NILs with the 1H introgression were resistant to LB and NB. Both are resistant to stripe rust. Therefore, the QTL conferring resistance to stripe rust is separable by recombination from the blast resistance QTL.

Crops that feed the world 4. Barley: a resilient crop? Strengths and weaknesses in the context of food security

“…3) Rice blast, caused by Magnaporthe grisea, is widely known as one of the most important diseases of rice worldwide, but can also infect barley, wheat and triticale (Anjos and Charchar 2000;Lima et al 2007;Urashima et al 2004). Both the foliage and more devastating head/neck phase of the disease have been reported on barley in South America and southeast Asia (Kongprakhon et al 2009;Lima and Minella 2003;Lima et al 2007). Rice blast of barley and wheat is increasing in South America (Agropages.…”

Construction of a single nucleotide polymorphism marker based QTL map and validation of resistance loci to bacterial wilt caused by Ralstonia solanacearum species complex in tomato

“…Near isogenic lines (NILs) have been used advantageously to identify and validate, as well as for fine mapping of QTLs. Moreover, NILs are highly useful to confirm that the QTL effect is indeed associated with the introgressed segments (Kinkade and Foolad 2013;Kongprakhon et al 2009;Lavaud et al 2015).…”

Host/nonhost status and genetics of resistance in barley against three pathotypes of Magnaporthe blast fungi

“…Therefore, the finding that Rmoq2 was effective against BR32, and not against PY67.1, was no surprise. Isolate-specific QTLs for blast resistance in barley have been already reported (Chen et al 2003;Kongprakhon et al 2009). Chen et al (2003) identified twelve QTLs for blast resistance in barley against three rice blast isolates; one was effective to all three isolates, and the others were effective to only one or two of the isolates.…”

“…This isolate and/or pathotype specificity is also supported by the association study, in which only one QTL out of 16 was associated with blast resistance to both the MoT and the MoO isolates. Kongprakhon et al (2009). mapped a large-effect resistance QTL effective against two barley and two rice blast isolates.…”