Figure 2 - available via license: Creative Commons Attribution 3.0 Unported
Content may be subject to copyright.
Life cycle of a heteroecious, macrocyclic cereal rust. The alternate host for stem rust-Puccinia graminis is Berberis vulgaris (barberry); for leaf rust-Puccinia triticina, Thalictrum speciosissimum (meadow rue); for crown rust-Puccinia coronata, Rhamnus cathartica (buckthorn). Illustration by Jackie Morrison, USDA-ARS.
Source publication
Rusts are important pathogens of angiosperms and gymnosperms including cereal crops and forest trees. With respect to cereals, rust fungi are among the most important pathogens. Cereal rusts are heteroecious and macrocyclic requiring two taxonomically unrelated hosts to complete a five spore stage life cycle. Cereal rust fungi are highly variable f...
Context in source publication
Context 1
... cereal rust fungi, P. graminis-causal pathogen of stem rust on wheat, oat, barley, and rye; P. striiformis-causal pathogen of wheat stripe rust; P. triticina-causal pathogen of wheat leaf rust, and P. coronata-casual pathogen of oat crown rust, complete their life cycles on two taxonomically unrelated hosts, and are thus heteroecious rusts. The cereal rusts are macrocyclic and have five distinct stages of teliospores, basidiospores, and urediniospores on cereal hosts, and pycniospores and aeciospores on the alternate hosts [6] (Figure 2). The urediniospores have a dikaryotic nuclear condition and are capable of cycling continuously on the cereal hosts. ...
Citations
... rust is a polycyclic fungal pathogen with a capability to produce new virulent phenotypes (races), faster than the release of new wheat varieties (Kolmer, 2013). ...
... Most of the named genes are associated with SR, conferring race-specific resistance against P. triticina. Hence, Lr genes, carried by many cultivars (e.g., Lr3, Lr10, Lr13, Lr17b, Lr26, and Lr37), have been overcome [17][18][19], and very few are still broadly effective currently. Only a small portion of them are APR genes [20], including Lr12, Lr13, Lr22a, Lr22b, Lr34, Lr35, Lr37, Lr46, Lr48, Lr49, Lr67, and Lr68, and few of these demonstrate slow rusting resistance. ...
... The continuous identification and selection of rust-resistant genetic resources is an important strategy employed by wheat breeding programs. The identification of resources with effective and durable resistance genes allows the efficient incorporation of these target genes into germplasm pools [1,19]. Breeding efforts have been undertaken to introgress various Lr genes into wheat breeding lines [69]. ...
Leaf rust (Puccinia triticina Eriks) is a wheat disease causing substantial yield losses in wheat production globally. The identification of genetic resources with permanently effective resistance genes and the generation of mutant lines showing increased levels of resistance allow the efficient incorporation of these target genes into germplasm pools by marker-assisted breeding. In this study, new mutant (M3 generation) lines generated from the rust-resistant variety Kazakhstanskaya-19 were developed using gamma-induced mutagenesis through 300-, 350-, and 400-Gy doses. In field trials after leaf rust inoculation, 75 mutant lines showed adult plant resistance. These lines were evaluated for resistance at the seedling stage via microscopy in greenhouse experiments. Most of these lines (89.33%) were characterized as resistant at both developmental stages. Hyperspectral imaging analysis indicated that infected leaves of wheat genotypes showed increased relative reflectance in visible and near-infrared light compared to the non-infected genotypes, with peak means at 462 and 644 nm, and 1936 and 2392 nm, respectively. Five spectral indexes, including red edge normalized difference vegetation index (RNDVI), structure-insensitive pigment index (SIPI), ratio vegetation index (RVSI), water index (WI), and normalized difference water index (NDWI), demonstrated significant potential for determining disease severity at the seedling stage. The most significant differences in reflectance between susceptible and resistant mutant lines appeared at 694.57 and 987.51 nm. The mutant lines developed were also used for the development and validation of KASP markers for leaf rust resistance genes Lr1, Lr2a, Lr3, Lr9, Lr10, and Lr17. The mutant lines had high frequencies of “a” resistance alleles (0.88) in all six Lr genes, which were significantly associated with seedling resistance and suggest the potential of favorable haplotype introgression through functional markers. Nine mutant lines characterized by the presence of “b” alleles in Lr9 and Lr10—except for one line with allele “a” in Lr9 and three mutant lines with allele “a” in Lr10—showed the progressive development of fungal haustorial mother cells 72 h after inoculation. One line from 300-Gy-dosed mutant germplasm with “b” alleles in Lr1, Lr2a, Lr10, and Lr17 and “a” alleles in Lr3 and Lr9 was characterized as resistant based on the low number of haustorial mother cells, suggesting the contribution of the “a” alleles of Lr3 and Lr9.
... Leaf rust, caused by Puccinia triticina Eriks. (Pt), is one of the most common diseases of wheat due to its frequent and widespread occurrence in most of the wheat-growing regions around the world (Kolmer 2013). Leaf rust occurs severely in wheat with frequent dew during the jointing through flowering stages (Xiao et al. 2022). ...
A novel leaf rust resistance locus located on a terminal segment (0–69.29 Mb) of Thinopyrum intermedium chromosome arm 7JsS has been introduced into wheat genome for disease resistance breeding.
Xiaoyan 78829, a wheat–Thinopyrum intermedium partial amphiploid, exhibits excellent resistance to fungal diseases in wheat. To transfer its disease resistance to common wheat (Triticum aestivum), we previously developed a translocation line WTT26 using chromosome engineering. Disease evaluation showed that WTT26 was nearly immune to 14 common races of leaf rust pathogen (Puccinia triticina) and highly resistant to Ug99 race PTKST of stem rust pathogen (P. graminis f. sp. tritici) at the seedling stage. It also displayed high adult plant resistance to powdery mildew (caused by Blumeria graminis f. sp. tritici). Cytogenetic and molecular marker analysis revealed that WTT26 carried a T4BS·7JsS chromosome translocation. Once transferred into the susceptible wheat genetic background, chromosome 7JsS exhibited its resistance to leaf rust, indicating that the resistance locus was located on this alien chromosome. To enhance the usefulness of this locus in wheat breeding, we further developed several new translocation lines with small Th. intermedium segments using irradiation and developed 124 specific markers using specific-locus amplified fragment sequencing, which increased the marker density of chromosome 7JsS. Furthermore, a refined physical map of chromosome 7JsS was constructed with 74 specific markers, and six bins were thus arranged according to the co-occurrence of markers and alien chromosome segments. Combining data from specific marker amplification and resistance evaluation, we mapped a new leaf rust resistance locus in the 0–69.29 Mb region on chromosome 7JsS. The translocation lines carrying the new leaf rust resistance locus and its linked markers will contribute to wheat disease-resistance breeding.
... Wheat leaf rust (Puccinia triticina) belongs to the economically most important obligate biotrophic pathogens of wheat (Bolton et al., 2008a;Bolton et al., 2008b;Kolmer, 2013). It is the causative agent of leaf rust, the most common rust of wheat worldwide reducing number of grains and thousand-grain weight, resulting in yield losses of up to 60% (Bancal et al., 2007;Bolton et al., 2008b;Kolmer, 2013). ...
... Wheat leaf rust (Puccinia triticina) belongs to the economically most important obligate biotrophic pathogens of wheat (Bolton et al., 2008a;Bolton et al., 2008b;Kolmer, 2013). It is the causative agent of leaf rust, the most common rust of wheat worldwide reducing number of grains and thousand-grain weight, resulting in yield losses of up to 60% (Bancal et al., 2007;Bolton et al., 2008b;Kolmer, 2013). Uredinia, the typical leaf rust fruiting bodies formed during the asexual life cycle, occur on the upper surface and bottom side of leaves on susceptible wheat cultivars with a diameter of up to 1.5 mm (Kolmer, 2005;Kolmer, 2013). ...
... It is the causative agent of leaf rust, the most common rust of wheat worldwide reducing number of grains and thousand-grain weight, resulting in yield losses of up to 60% (Bancal et al., 2007;Bolton et al., 2008b;Kolmer, 2013). Uredinia, the typical leaf rust fruiting bodies formed during the asexual life cycle, occur on the upper surface and bottom side of leaves on susceptible wheat cultivars with a diameter of up to 1.5 mm (Kolmer, 2005;Kolmer, 2013). These uredinia harbor dikaryotic uredospores of approximately 20 μm. ...
Wheat leaf rust (Puccinia triticina) is one of the most significant fungal diseases of wheat, causing substantial yield losses worldwide. Infestation is currently being reduced by fungicide treatments and mostly vertical resistance. However, these measures often break down when the fungal virulence pattern changes, resulting in a breakdown of vertical resistances. In contrast, the prehaustorial resistance (phr) that occurs in the einkorn–wheat leaf rust interaction is race-independent, characterized by an early defense response of plants during the prehaustorial phase of infestation. Einkorn (Triticum monococcum) is closely related to Triticum urartu as a progenitor of wheat and generally shows a high level of resistance against leaf rust of wheat. Hence, einkorn can serve as a valuable source to improve the level of resistance to the pathogen in future wheat lines. In particular, einkorn accession PI272560 is known to exhibit a hypersensitive prehaustorial effector triggered immune reaction, preventing the infection of P. triticina. Remarkably, this effector-triggered immune reaction turned out to be atypical as it is non-race-specific (horizontal). To genetically dissect the prehaustorial resistance (phr) in PI272560, a biparental F2 population of 182 plants was established after crossing PI272560 with the susceptible T. boeoticum accession 36554. Three genetic maps comprising 2,465 DArT-seq markers were constructed, and a major QTL was detected on chromosome 5A. To locate underlying candidate genes, marker sequences flanking the respective QTL were aligned to the T. urartu reference genome and transcriptome data available from the parental accessions were used. Within the QTL interval of approximately 16.13 million base pairs, the expression of genes under inoculated and non-inoculated conditions was analyzed via a massive analysis of cDNA (MACE). Remarkably, a single gene located 3.4 Mbp from the peak marker within the major QTL was upregulated (20- to 95-fold) after the inoculation in the resistant accession in comparison to the susceptible T. boeoticum accession. This gene belongs to a berberine bridge enzyme-like protein that is suspected to interact on the plant surface with glycoside hydrolases (GH) secreted by the fungus and to induce a hypersensitive defense reaction in the plant after fungal infections.
... Especially interesting is the resistance of a non-specific nature -the "slow rusting" type, or the retarded development of the pathogen. The cultivars possessing this type of resistance allow the pathogen to sporulate on them, to attack them to a moderate degree, without forcing the pathogen to develop new more aggressive races (Knott, 1989;Kolmer, 2013;Singh et al., 2016). The genes determining this type of resistance are related to such factors as pustule size, infection frequency, latent period, and are most often defined as "slow rusting genes" (Caldwell, 1968;Kolmer, 1996;Ellis at al., 2014). ...
The response of 250 common winter wheat breeding lines was investigated for resistance to the causative agent of Puccinia triticina under conditions of an infected field on the territory of Dobrudzha Agricultural Institute – General Toshevo, Bulgaria, during three successive seasons. Twenty lines with different degrees of resistance under field conditions were selected. Multi-pathotype testing was used to study the response of these lines at seedling stage under greenhouse conditions to individual pathotypes of P. triticina . Based on the response of the lines at seedling and adult stages, we found out that 20 % of them carried race-specific resistance. One of the lines (99/08-52) reacted with full resistance to the pathotypes used under greenhouse conditions. The reaction demonstrated by this line coincided with the response of isogenic lines carrying the genes Lr9, Lr19, Lr22a, Lr22b and Lr25 . The other three lines (19/06-108, 82/08-43 and 82/08-35) showed a resistant reaction to 6 or 5 of the pathotypes used in the study. Their response partially coincided with the reaction of 5 isogenic lines, and the presence of some of these genes in the above lines is quite possible. Lines carrying this type of resistance are to be subjected to further genetic and breeding investigations to prove the presence of a race-specific gene. Twenty-five percent of the lines combined partial race-specific resistance at seedling stage with the resistance of race non-specific nature at adult stage. Forty percent of all studied lines carried race non-specific resistance, and 15 % of the lines possessed resistance of the “slow rusting” type. As a result of the study we carried out, the lines that demonstrated stable resistance to leaf rust can provide sufficient protection of the host and can be included in the breeding programs for developing varieties resistant to P. triticina .
... Besides changes in several physiological processes of the host plant, leaf rust can also affect translocation of water and nutrients, transpiration, and regulation of growth (Lucas, 1998). Additionally, rust infections can lead to the spread of chlorotic and necrotic areas (Kolmer, 2013), related to the loss of photosynthetic function, whereas the disease affects the amount of chlorophyll and its biosynthesis breaks down (Long & Ort, 2010). The reduction of photosynthetic activity is usually correlated with the visible area of impact (Copolovici et al. 2014 ...
Leaf rust caused by Puccinia triticina Erikss. can have devastating effects on wheat (Triticum aestivum L.), causing severe economic losses. This comprehensive study serves to facilitate our understanding of the impact of carbohydrate and antioxidant metabolism in association with sensor-based phenotyping and leaf rust stress responses in wheat seedlings. After 24 h of inoculation (hai) very susceptible variety to leaf rust (Ficko) increased cell-wall invertase (cwInv; EC 3.2.1.26), compared to other varieties that significantly increased cwInv later. This could mean that the Ficko variety cannot defend itself from leaf rust infections once symptoms have started to develop. Also, Ficko had significantly decreased amounts of cytoplasmic invertase (cytInv; EC 3.2.1.26) at 8 hai. The downregulation of cytInv in susceptible plants may facilitate the maintenance of elevated apoplastic sucrose availability favoring the pathogen. The significant role of vacuolar invertase (vacInv; EC 3.2.1.26) in moderately resistant varieties was recorded. Also, a significant decrease of glucose-6-phosphate dehydrogenase (G6PDH; EC 1.1.1.49) and UDP-glucose pyrophosphorylase (UGPase; EC 2.7.7.9) in moderately resistant varieties might restrict normal development of leaf rust due to reduced sugar. During plant–pathogen interaction, when the invader spreads systemically throughout the plant, the main role of ascorbate peroxidase (APX; EC 1.11.1.11) activity in one moderately resistant variety (Olimpija) and catalase (CAT; EC 1.11.1.6) activity in another moderately resistant variety (Alka) is to protect the plant against oxidative damage in the early stages of infection. Non-invasive phenotyping with a sensor-based technique could be used as a rapid method for pre-symptomatic determination of wheat leaf rust resistance or susceptibility.
... (accessed on 20 April 2023)) [3]. The most prevalent disease in wheat is leaf rust, which is brought on by the parasitic basidiomycete Puccinia triticina [4]. Due to their small size, rust spores can be widely dispersed over wide geographic areas by wind [5]. ...
Leaf rust (LR) is the most widespread disease of common wheat worldwide. In order to evaluate leaf rust resistance, 70 uncharacterized wheat cultivars and promising lines with unknown leaf rust resistance genes (Lr genes) were exposed to Kazakhstani Puccinia triticina (Pt) races at the seedling stage. Field tests were performed to characterize leaf rust responses at the adult plant growth stage in the 2020–2021 and 2021–2022 cropping seasons. The wheat collection showed phenotypic diversity when tested with two virulent races of Pt. Thirteen wheat genotypes (18.6%) showed high resistance at both seedling and adult plant stages. In most cases, breeding material originating from international nurseries showed higher resistance to LR. Nine Lr genes, viz. Lr9, Lr10, Lr19, Lr26, Lr28, Lr34, Lr37, Lr46, and Lr68, either singly or in combination, were identified in 47 genotypes. Known Lr genes were not detected in the remaining 23 genotypes. The most commonly identified resistance genes were Lr37 (17 cultivars), Lr34 (16 cultivars), and Lr46 (10 cultivars), while Lr19, Lr68, Lr26, and Lr28 were the least frequent. Four Lr genes were identified in Keremet and Hisorok, followed by three Lr genes in Aliya, Rasad, Reke, Mataj, Egana and Almaly/Obri. The molecular screening revealed twenty-nine carriers of a single Lr gene, ten carriers of two genes, six carriers of three genes, and two carriers of four genes. Most of these accessions showed a high and moderate level of APR (Adult plant resistance) and may be utilized for the incorporation of Lr genes in well-adapted wheat cultivars. The most effective combination was Lr37, Lr34, and Lr68, the carriers of which were characterized by a low disease susceptibility index. The obtained results will facilitate breeding programs for wheat resistance in Kazakhstan.
... Bread wheat (Triticum aestivum; 2n=6x=42; AABBDD genome) is one of the most widely cultivated crops worldwide 4 . The fungal pathogen Puccinia triticina (Pt) causes leaf rust, which is among the most widespread and devastating wheat diseases, resulting in annual production losses of ~25 million tons 5,6 . Of the 69 known leaf rust (Lr) resistance genes in wheat, 28 were introgressed from the secondary and tertiary gene pools through interspecific hybridizations 7 . ...
The introgression of chromosome segments from wild relatives is an established strategy to enrich crop germplasm with disease-resistance genes¹. Here we use mutagenesis and transcriptome sequencing to clone the leaf rust resistance gene Lr9, which was introduced into bread wheat from the wild grass species Aegilops umbellulata². We established that Lr9 encodes an unusual tandem kinase fusion protein. Long-read sequencing of a wheat Lr9 introgression line and the putative Ae. umbellulata Lr9 donor enabled us to assemble the ~28.4-Mb Lr9 translocation and to identify the translocation breakpoint. We likewise cloned Lr58, which was reportedly introgressed from Aegilopstriuncialis³, but has an identical coding sequence compared to Lr9. Cytogenetic and haplotype analyses corroborate that the two genes originate from the same translocation event. Our work sheds light on the emerging role of kinase fusion proteins in wheat disease resistance, expanding the repertoire of disease-resistance genes for breeding.
... Leaf rust, stem rust, and stripe rust are important diseases of wheat worldwide (Sinha and Chen, 2021). Wheat rusts are caused by obligate, biotrophic fungal pathogens belonging to the family Puccinacae that can spread thousands of miles by wind and cause significant economic losses around the globe (Kolmer, 2013). For instance, only yellow or stripe rust of wheat causes up to 100% yield losses to susceptible varieties (Chen, 2005). ...
Wheat (Triticum aestivum L.) diseases are major factors responsible for substantial yield losses worldwide, which affect global food security. For a long time, plant breeders have been struggling to improve wheat resistance against major diseases by selection and conventional breeding techniques. Therefore, this review was conducted to shed light on various gaps in the available literature and to reveal the most promising criteria for disease resistance in wheat. However, novel techniques for molecular breeding in the past few decades have been very fruitful for developing broad-spectrum disease resistance and other important traits in wheat. Many types of molecular markers such as SCAR, RAPD, SSR, SSLP, RFLP, SNP, and DArT, etc., have been reported for resistance against wheat pathogens. This article summarizes various insightful molecular markers involved in wheat improvement for resistance to major diseases through diverse breeding programs. Moreover, this review highlights the applications of marker assisted selection (MAS), quantitative trait loci (QTL), genome wide association studies (GWAS) and the CRISPR/Cas-9 system for developing disease resistance against most important wheat diseases. We also reviewed all reported mapped QTLs for bunts, rusts, smuts, and nematode diseases of wheat. Furthermore, we have also proposed how the CRISPR/Cas-9 system and GWAS can assist breeders in the future for the genetic improvement of wheat. If these molecular approaches are used successfully in the future, they can be a significant step toward expanding food production in wheat crops.
... There are myriads of individuals in the populations of rust fungi on large-scale wheat monocrops. In these populations, active evolutionary processes are aimed at overcoming plant resistance [21,23,77]. The spreading rust fungi by the aerogenic way promotes the migration of virulent forms to new territories [78]. ...
The damage to wheat crops by stem rust poses a threat to the food security of the world’s population. The species Thinopyrum ponticum (Podpěra, 1902) (Z.-W. Liu and R.-C. Wang, 1993) is a non-host for the stem rust fungus Puccinia graminis f. sp. tritici Eriks. and Henn. (Pgt). The Sr24, Sr25, and Sr26 genes, transferred from the Th. ponticum to the wheat gene pool, protect cultivars from the disease in different regions of the world. The study of the non-host resistance (NHR) of Th. ponticum and the effects of the introgressed Sr24, Sr25, and Sr26 genes in wheat is important for breeding cultivars with durable resistance to stem rust. The aim of the research is to study the interaction of Pgt with Th. ponticum and common wheat lines with the Sr24, Sr25, and Sr26 genes, in addition to determining the role of ROS in resistance. Wheat lines with Sr24, Sr25, and Sr26 were resistant to the West Siberian Pgt population. Using cytological methods, it was found that the NHR of Th. ponticum and Sr24, Sr25, and Sr26 led to inhibition of the most inoculumdevelopment on the plant surface. This was mainly due to the suppression of the appressoria development and their death at the stage of penetration into the stomata. Upon contact of Pgt appressoria with stomatal guard cells, the generation of the superoxide anion O2•− was revealed. This interaction is similar to the stomatal immunity of Arabidopsis thaliana to non-pathogenic bacteria. The results of our studies show that the Sr24, Sr25, and Sr26 genes reproduce the action of some NHR mechanisms in wheat.
