Stripe rust, caused by
f. sp.
(
), is one of the most destructive diseases of wheat in the world. Genetic resistance is the best strategy for control of the disease. Spring wheat landrace PI 181410 ...has shown high level resistance to stripe rust. The present study characterized the landrace to have both race-specific all-stage resistance and nonrace-specific high-temperature adult-plant (HTAP) resistance. To map quantitative trait loci (QTL) for the resistance in PI 181410, it was crossed with Avocet S (AvS), from which a recombinant inbred line population was developed. The F
-F
populations were consecutively phenotyped for stripe rust response in multiple field environments under natural
infection, and the F
population was phenotyped in seedlings at low temperature and in adult-plant stage with selected
races in the greenhouse. The F
population was genotyped using the 90K wheat SNP chip. Three QTL,
,
, and
.1, from PI 181410 for all-stage resistance, were mapped on chromosome arms 4AS, 4BL, and 5BL, respectively. Four QTL,
,
,
, and
, were identified from PI 181410 for HTAP resistance and mapped to 1BL, 4BL, 5AS, and 5BL, respectively. Two QTL with minor effects on stripe rust response were identified from AvS and mapped to 2BS and 2BL. Four of the QTL from PI 181410 and one from AvS were potentially new. As the 4BL QTL was most effective and likely a new gene for stripe rust resistance, three kompetitive allele specific PCR (KASP) markers were developed for incorporating this gene into new wheat cultivars.
Abstract Fungal diseases, such as powdery mildew and rusts, significantly affect the quality and yield of wheat. Pyramiding diverse types of resistance genes into cultivars represents the preferred ...strategy to combat these diseases. Moreover, achieving collaborative improvement between diseases resistance, abiotic stress, quality, and agronomic and yield traits is difficult in genetic breeding. In this study, the wheat cultivar, Guinong 29 (GN29), showed high resistance to powdery mildew and stripe rust at both seedling and adult plant stages, and was susceptible to leaf rust at the seedling stage but slow resistance at the adult-plant stage. Meanwhile, it has elite agronomic and yield traits, indicating promising coordination ability among multiple diseases resistance and other key breeding traits. To determine the genetic basis of these elite traits, GN29 was tested with 113 molecular markers for 98 genes associated with diseases resistance, stress tolerance, quality, and adaptability. The results indicated that two powdery mildew resistance ( Pm ) genes, Pm2 and Pm21 , confirmed the outstanding resistance to powdery mildew through genetic analysis, marker detection, genomic in situ hybridization (GISH), non-denaturing fluorescence in situ hybridization (ND-FISH), and homology-based cloning; the stripe rust resistance ( Yr ) gene Yr26 and leaf rust resistance ( Lr ) genes Lr1 and Lr46 conferred the stripe rust and slow leaf rust resistance in GN29, respectively. Meanwhile, GN29 carries dwarfing genes Rht-B1b and Rht-D1a , vernalization genes vrn-A1 , vrn-B1 , vrn-D1 , and vrn-B3 , which were consistent with the phenotypic traits in dwarf characteristic and semi-winter property; carries genes Dreb1 and Ta-CRT for stress tolerance to drought, salinity, low temperature, and abscisic acid (ABA), suggesting that GN29 may also have elite stress-tolerance ability; and carries two low-molecular-weight glutenin subunit genes Glu-B3b and Glu-B3bef which contributed to high baking quality. This study not only elucidated the genetic basis of the elite traits in GN29 but also verified the capability for harmonious improvement in both multiple diseases resistance and other comprehensive traits, offering valuable information for breeding breakthrough-resistant cultivars.
Powdery mildew of wheat (
Triticum aestivum
), caused by
Blumeria graminis
f.sp.
tritici
(
Bgt
), is a destructive disease that seriously threatens the yield and quality of its host. Identifying ...resistance genes is the most attractive and effective strategy for developing disease-resistant cultivars and controlling this disease. In this study, a wheat breeding line Yannong 99102-06188 (YN99102), an elite derivative line from the same breeding process as the famous wheat cultivar Yannong 999, showed high resistance to powdery mildew at the whole growth stages. Genetic analysis was carried out using
Bgt
isolate E09 and a population of YN99102 crossed with a susceptible parent Jinhe 13–205 (JH13–205). The result indicated that a single recessive gene, tentatively designated
pmYN99102
, conferred seedling resistance to the
Bgt
isolate E09. Using bulked segregant exome capture sequencing (BSE-Seq),
pmYN99102
was physically located to a ~33.7 Mb (691.0–724.7 Mb) interval on the chromosome arm 2BL, and this interval was further locked in a 1.5 cM genetic interval using molecular markers, which was aligned to a 9.0 Mb physical interval (699.2–708.2 Mb). Based on the analysis of physical location, origin, resistant spectrum, and inherited pattern,
pmYN99102
differed from those of the reported powdery mildew (
Pm
) resistance genes on 2BL, suggesting
pmYN99102
is most likely a new
Pm
gene/allele in the targeted interval. To transfer
pmYN99102
to different genetic backgrounds using marker-assisted selection (MAS), 18 closely linked markers were tested for their availability in different genetic backgrounds for MAS, and all markers expect for
YTU103-97
can be used in MAS for tracking
pmYN99102
when it transferred into those susceptible cultivars.
Powdery mildew, caused by
f. sp.
(
), is one of the most destructive fungal diseases threatening global wheat production. Exploring powdery mildew resistance (
) gene(s) and dissecting the molecular ...mechanism of the host resistance are critical to effectively and reasonably control this disease. Durum wheat (
L. var.
Desf.) is an important gene donor for wheat improvement against powdery mildew. In this study, a resistant durum wheat accession W762 was used to investigate its potential resistance component(s) and profile its expression pattern in responding to
invasion using bulked segregant RNA-Seq (BSR-Seq) and further qRT-PCR verification. Genetic analysis showed that the powdery mildew resistance in W762 did not meet monogenic inheritance and complex genetic model might exist within the population of W762 × Langdon (susceptible durum wheat). After BSR-Seq, 6,196 consistently different single nucleotide polymorphisms (SNPs) were called between resistant and susceptible parents and bulks, and among them, 763 SNPs were assigned to the chromosome arm 7B. Subsequently, 3,653 differentially expressed genes (DEGs) between resistant and susceptible parents and bulks were annotated and analyzed by Gene Ontology (GO), Cluster of Orthologous Groups (COG), and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment. The potential regulated genes were selected and analyzed their temporal expression patterns following
inoculation. As a result, nine disease-related genes showed distinctive expression profile after
invasion and might serve as potential targets to regulate the resistance against powdery mildew in W762. Our study could lay a foundation for analysis of the molecular mechanism and also provide potential targets for the improvement of durable resistance against powdery mildew.
Powdery mildew is one of the most severe diseases affecting wheat yield and quality and is caused by
f. sp.
(
). Host resistance is the preferred strategy to prevent this disease. However, the narrow ...genetic basis of common wheat has increased the demand for diversified germplasm resources against powdery mildew. Wheat relatives, especially the secondary gene pool of common wheat, are important gene donors in the genetic improvement of common wheat because of its abundant genetic variation and close kinship with wheat. In this study, a series of 137 wheat relatives, including 53
L. (2n = 2x = 14, AA), 6
Gandilyan (2n = 2x = 14, AA), 9
Zhuk. (2n = 4x = 28, AAGG), 66
subsp
(2n = 6x = 42, AABBDD), and 3
(2n = 2x = 14, SS) were systematically evaluated for their powdery mildew resistance and composition of
genes. Out of 137 (60.58%) accessions, 83 were resistant to
isolate E09 at the seedling stage, and 116 of 137 (84.67%) wheat relatives were resistant to the mixture of
isolates at the adult stage. This indicates that these accessions show a high level of resistance to powdery mildew. Some 31 markers for 23 known
genes were used to test these 137 accessions, and, in the results, only
,
,
,
, and
were detected. Among them, three
alleles (
,
, and
) were identified in 4
. subsp
accessions. q-RT PCR further confirmed that
alleles played a role in disease resistance in these four accessions. The phylogenetic tree showed that the kinship of
was close to
and
. This study not only provides reference information and valuable germplasm resources for breeding new wheat varieties with disease resistance but also lays a foundation for enriching the genetic basis of wheat resistance to powdery mildew.
Identification and mapping new powdery mildew resistance (Pm) genes is important for resistance breeding in wheat. Common wheat (Triticum aestivum L.) line X3986-2 was tested against 27 isolates of ...Blumeria graminis f. sp. tritici. To identify the Pm gene(s) in X3986-2, an F₂ population and its derived F₂:₃ lines were developed from a cross between X3986-2 and susceptible line Mingxian169. Segregation ratios indicated the presence of a single dominant Pm locus, tentatively designated PmX3986-2. Bulked segregant analysis was applied to screen for molecular markers linked to PmX3986-2. Two sequence characterized amplified region (SCAR) markers SCAR112 and SCAR203, and five simple sequence repeat markers CFD40, CFD78, CFD81, GWM293 and WMC443 on chromosome 5D were linked to PmX3986-2, with CFD81 and SCAR112 flanking PmX3986-2 at 0.6 and 1.5 cM, respectively. This suggests that PmX3986-2 may be a novel allele of loci Pm2, Pm46 and PmLX66 on chromosome arm 5DS. PmX3986-2 with its tightly linked DNA markers should be useful for broadening the genetic basis of Pm and rapidly transferring the resistance gene to susceptible cultivars or for us in gene pyramiding for resistance breeding.
Stripe rust resistance gene YrC591, present in wheat cultivar C591, is effective against currently important Puccinia striiformis Westend. f. sp. tritici isolates in China. An F₂:₃ population (127 ...lines) was developed by crossing C591 with susceptible cultivar Taichung 29. Thirty four simple sequence repeat (SSR) and 155 sequence tagged site (STS) markers located on chromosome 7BL were used to perform bulk segregant analysis. Eight SSR markers, cfa2040, wmc273, wmc166, gwm984, barc32 wmc276, barc182 and gwm146, and 6 STS markers, mag1714, mag1757, mag1811, BE425120, BE471173 and BG607810, were polymorphic between the parents and contrasting resistant and susceptible DNA pools. F₂:₃ lines were genotyped with these polymorphic markers. Linkage analysis indicated that YrC591 was flanked by Xmag1714 and Xbarc182 with genetic distances of 1.2 and 0.4 cM, respectively. In addition, validation of the SSR markers cfa2040, wmc273 and barc32, and STS markers mag1714 and BE425120 was carried out using wheat lines with C591 as a parent, indicating that these markers should be effective in tracing this gene in marker-assisted selection.
KEY MESSAGE : 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.
Key message
An allele of
Pm2
for wheat powdery mildew resistance was identified in a putative
Agropyron cristatum
-derived line and used in wheat breeding programs.
Powdery mildew (caused by
Blumeria ...graminis
f. sp.
tritici
,
Bgt
) is one of the most devastating wheat diseases worldwide. It is important to exploit varied sources of resistance from common wheat and its relatives in resistance breeding. KM2939, a Chinese breeding line, exhibits high resistance to powdery mildew at both the seedling and adult stages. It carries a single dominant powdery mildew resistance
(Pm
) allele of
Pm2
, designated
Pm2b
, the previous allelic designation
Pm2
will be re-designated as
Pm2a
.
Pm2b
was mapped to chromosome arm 5DS and flanked by sequence characterized amplified region (SCAR) markers
SCAR112
and
SCAR203
with genetic distances of 0.5 and 1.3 cM, respectively. Sequence tagged site (STS) marker
Mag6176
and simple sequence repeat (SSR) marker
Cfd
81 co-segregated with
SCAR203
.
Pm2b
differs in specificity from donors of
Pm2a
,
Pm46
and
PmLX66
on chromosome arm 5DS. Allelism tests indicated that
Pm2b
,
Pm2a
and
PmLX66
are allelic. Therefore,
Pm2b
appears to be a new allele at the
Pm2
locus. The closely linked markers were used to accelerate transfer of
Pm2b
to wheat cultivars in current production.
Powdery mildew, caused by
Blumeria graminis
f. sp.
tritici
(
Bgt
), is a severe disease that affects the yield and quality of wheat. Popularization of resistant cultivars in production is the ...preferred strategy to control this disease. In the present study, the Chinese wheat breeding line Jimai 809 showed excellent agronomic performance and high resistance to powdery mildew at the whole growth stage. To dissect the genetic basis for this resistance, Jimai 809 was crossed with the susceptible wheat cultivar Junda 159 to produce segregation populations. Genetic analysis showed that a single dominant gene, temporarily designated
PmJM809
, conferred the resistance to different
Bgt
isolates.
PmJM809
was then mapped on the chromosome arm 2BL and flanked by the markers
CISSR02g-1
and
CIT02g-13
with genetic distances 0.4 and 0.8 cM, respectively, corresponding to a physical interval of 704.12–708.24 Mb.
PmJM809
differed from the reported
Pm
genes on chromosome arm 2BL in origin, resistance spectrum, physical position and/or genetic diversity of the mapping interval, also suggesting
PmJM809
was located on a complex interval with multiple resistance genes. To analyze and screen the candidate gene(s) of
PmJM809
, six genes related to disease resistance in the candidate interval were evaluated their expression patterns using an additional set of wheat samples and time-course analysis post-inoculation of the
Bgt
isolate E09. As a result, four genes were speculated as the key candidate or regulatory genes. Considering its comprehensive agronomic traits and resistance findings,
PmJM809
was expected to be a valuable gene resource in wheat disease resistance breeding. To efficiently transfer
PmJM809
into different genetic backgrounds, 13 of 19 closely linked markers were confirmed to be suitable for marker-assisted selection. Using these markers, a series of wheat breeding lines with harmonious disease resistance and agronomic performance were selected from the crosses of Jimai 809 and several susceptible cultivars.
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