Wheat rust resistance research at CSIRO

2007 ◽  
Vol 58 (6) ◽  
pp. 507 ◽  
Author(s):  
Jeffrey G. Ellis ◽  
Rohit Mago ◽  
Raja Kota ◽  
Peter N. Dodds ◽  
Helen McFadden ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Molecular Basis ◽  
Rust Resistance ◽  
Gene Sequence ◽  
Adult Plant Resistance ◽  
Sequence Data ◽  
Adult Plant ◽  
Rust Diseases ◽  
Efficient Breeding ◽  
Wheat Rust

Although chemical control is available for rust diseases in wheat, economic and environmental factors favour genetic solutions. Maintenance and improvement of levels of resistance and durability of the genetic control of the 3 wheat rust diseases will occur with the application of DNA markers for pyramiding resistance genes. Information about the molecular basis of rust resistance, including durable, adult-plant resistance, coming from studies in model species such as flax and flax rust and from studies of wheat and barley, will provide knowledge for new biotechnological approaches to rust resistance. Increasing cereal gene sequence data will improve the efficiency of cloning disease resistance genes and, together with the rapid progress in understanding the molecular basis of rust resistance, will make it possible to construct transgenic plants with multiple rust resistance genes at a single locus, which will provide efficient breeding and increased durability of rust resistance.

Seedling resistances to rust diseases in international triticale germplasm

2010 ◽  
Vol 61 (12) ◽  
pp. 1036 ◽  
Author(s):  
J. Zhang ◽  
C. R. Wellings ◽  
R. A. McIntosh ◽  
R. F. Park
Keyword(s):  
Leaf Rust ◽  
Stripe Rust ◽  
Plant Resistance ◽  
Stem Rust ◽  
Rust Resistance ◽  
Adult Plant Resistance ◽  
Stem Rust Resistance ◽  
Adult Plant ◽  
Seedling Resistance ◽  
Rust Diseases

Seedling resistances to stem rust, leaf rust and stripe rust were evaluated in the 37th International Triticale Screening Nursery, distributed by the International Wheat and Maize Improvement Centre (CIMMYT) in 2005. In stem rust tests, 12 and 69 of a total of 81 entries were postulated to carry Sr27 and SrSatu, respectively. When compared with previous studies of CIMMYT triticale nurseries distributed from 1980 to 1986 and 1991 to 1993, the results suggest a lack of expansion in the diversity of stem rust resistance. A total of 62 of 64 entries were resistant to five leaf rust pathotypes. In stripe rust tests, ~93% of the lines were postulated to carry Yr9 alone or in combination with other genes. The absence of Lr26 in these entries indicated that Yr9 and Lr26 are not genetically associated in triticale. A high proportion of nursery entries (63%) were postulated to carry an uncharacterised gene, YrJackie. The 13 lines resistant to stripe rust and the 62 entries resistant to leaf rust represent potentially useful sources of seedling resistance in developing new triticale cultivars. Field rust tests are needed to verify if seedling susceptible entries also carry adult plant resistance.

Breeding triple rust resistant wheat cultivars for Australia using conventional and marker-assisted selection technologies

2007 ◽  
Vol 58 (6) ◽  
pp. 576 ◽  
Author(s):  
H. S. Bariana ◽  
G. N. Brown ◽  
U. K. Bansal ◽  
H. Miah ◽  
G. E. Standen ◽  
...  
Keyword(s):  
Leaf Rust ◽  
Resistance Genes ◽  
Plant Resistance ◽  
Stem Rust ◽  
Marker Assisted Selection ◽  
Rust Resistance ◽  
Adult Plant Resistance ◽  
Adult Plant ◽  
Wheat Cultivars ◽  
The University

Stem rust susceptibility of European wheats under Australian conditions posed a significant threat to wheat production for the early British settlers in Australia. The famous Australian wheat breeder, William Farrer, tackled the problem of stem rust susceptibility through breeding fast-maturing wheat cultivars. South-eastern Australia suffered a severe stem rust epidemic in 1973, which gave rise to a national approach to breeding for rust resistance. The National Wheat Rust Control Program was set up in 1975, modelled on the University of Sydney’s own rust resistance breeding program, at the University of Sydney Plant Breeding Institute, Castle Hill (now Cobbitty). Back-crossing of a range of sources of resistance provided genetically diverse germplasm for evaluation in various breeding programs. Current efforts are directed to building gene combinations through marker-assisted selection. Major genes for resistance to stem rust and leaf rust are being used in the back-crossing program of the ACRCP to create genetic diversity among Australian germplasm. Stripe rust and to a lesser extent leaf rust resistance in the Australian germplasm is largely based on combinations of adult plant resistance genes and our knowledge of their genomic locations has increased. Additional genes, other than Yr18/Lr34 and Yr29/Lr46, appeared to control adult plant resistance to both leaf rust and stripe rust. Two adult-plant stem rust resistance genes have also been identified. The development of selection technologies to achieve genotype-based selection of resistance gene combinations in the absence of bioassays has evolved in the last 5 years. Robust molecular markers are now available for several commercially important rust resistance genes. Marker-assisted selection for rust resistance is performed routinely in many wheat-breeding programs. Modified pedigree and limited back-cross methods have been used for breeding rust-resistant wheat cultivars in the University of Sydney wheat-breeding program. The single back-cross methodology has proved more successful in producing cultivars with combinations of adult plant resistance genes.

Genetics of adult-plant leaf-rust resistance in four Indian and two Australian bread wheat cultivars

Genome ◽  
1994 ◽  
Vol 37 (3) ◽  
pp. 436-439 ◽  
Author(s):  
F Shiwani ◽  
R. G. Saini
Keyword(s):  
Leaf Rust ◽  
Bread Wheat ◽  
Resistance Genes ◽  
Plant Resistance ◽  
Rust Resistance ◽  
Adult Plant Resistance ◽  
Leaf Rust Resistance ◽  
Adult Plant ◽  
Wheat Cultivars ◽  
Partial Dominance

Genetic studies for leaf-rust resistance were conducted on four Indian (CPAN1235, HD2135, HP1209, and VL404) and two Australian (CSP44 and Oxley) bread wheat cultivars. The F2 and F3 plants from their crosses with each other and with susceptible cultivar Agra Local were tested against a mixture of pathotypes 77-1 and 77-2 (variants of race 77). Disease scores on F1's from resistant/susceptible parent crosses indicated partial dominance of resistance in these wheats. The six cultivars have two adult-plant resistance genes each. Their intercrosses revealed similar resistance gene(s) in CSP44 and Oxley, and CPAN1235 and HP1209. The six wheats appear to carry at least seven diverse leaf-rust resistance genes (temporarily named LrI to LrO) against pathotypes 77-1 + 77-2. Adult-plant resistance is additive and therefore the combinations of partially effective resistance genes identified in this study can provide higher levels of resistance. Because these genes are of hexaploid origin, they can be easily exploited in breeding programs. Furthermore, two or more resistance genes from the six wheat cultivars when combined with Lr34 are likely to impart durable resistance to leaf rust.Key words: adult-plant resistance, leaf-rust resistance, wheat, Puccinia recondita, Triticum aestivum.

scholarly journals Identification of Wheat Leaf Rust Resistance Genes in Chinese Wheat Cultivars and the Improved Germplasms

Plant Disease ◽  
2020 ◽  
Vol 104 (10) ◽  
pp. 2669-2680
Author(s):  
Hui Wu ◽  
Zhanhai Kang ◽  
Xing Li ◽  
Yanyan Li ◽  
Yi Li ◽  
...  
Keyword(s):  
Leaf Rust ◽  
Resistance Genes ◽  
Plant Resistance ◽  
Rust Resistance ◽  
Adult Plant Resistance ◽  
Natural Infection ◽  
Leaf Rust Resistance ◽  
Adult Plant ◽  
Wheat Cultivars ◽  
Lr Genes

Leaf rust is an important wheat disease that is a significant hindrance for wheat production in most areas of the world. Breeding resistant cultivars can effectively and economically control the disease. In the present study, a wheat collection consisting of 100 cultivars from China and 18 improved germplasms from global landrace donors together with 36 known single Lr gene lines were tested with 20 strains of Puccinia triticina Eriks. in the seedling stage to postulate the Lr gene in the cultivars and germplasms. In addition, 12 diagnostic molecular markers specific to 10 Lr genes were used to detect the presence of the Lr genes in the wheat collection. Resistance to leaf rust of these cultivars at the adult plant stage was tested in fields under natural infection during the 2016 to 2018 cropping seasons in Baoding, Hebei Province. The gene postulation combined with molecular marker detection showed that six Lr genes (Lr1, Lr26, Lr33, Lr34, Lr45, and Lr46) were identified in 44 wheat accessions, including 37 cultivars and seven improved germplasms. Among the 44 wheat accessions postulated with Lr genes, Lr1 was present in four accessions, Lr26 in 12 accessions, Lr33 in two accessions, Lr34 in 14 accessions, Lr45 in three accessions, and Lr46 in 16 accessions. In the collection of 118 cultivars/germplasms, 34 wheat lines displayed adult-plant resistance carrying Lr34, Lr46, and/or underdetermined genes. Therefore, a high level of leaf rust resistance can be achieved through the combination of all-stage resistance and adult-plant resistance genes together in wheat cultivars.

Transfer of leaf and stripe rust resistance genes Lr19 and Yr15 in to a susceptible wheat cultivar HS295

2019 ◽  
Vol 79 (3) ◽  
Author(s):  
Pratima Sharma ◽  
Madhu Patial ◽  
Dharam Pal ◽  
S. C. Bhardwaj ◽  
Subodh . Kumar ◽  
...  
Keyword(s):  
Rust Resistance ◽  
Ssr Marker ◽  
Scar Marker ◽  
Adult Plant Resistance ◽  
Wheat Cultivar ◽  
Stripe Rust Resistance ◽  
Adult Plant ◽  
Potential Donor ◽  
Seedling Resistance ◽  
Breeding Lines

The present study was conducted to transfer multiple rust resistance in a popular but rust susceptible wheat cultivar HS295. Selected derivatives WBM3632 and WBM3635 have been developed from a cross, HS295*2/FLW20//HS295*2/ FLW13 using bulk-pedigree method of breeding. Advance line WBM3697 selected from a breeding line WBM3532 was named as HS661. This line was evaluated for seedling resistance to a wide array of rust pathotypes and found to possess resistance to all the three rusts. HS661 was also tested under field conditions and showed adult plant resistance to leaf rust (AC1=0.6), stem rust (ACI=2.7) and strpe rust (AC1=3.8). Among 34 F3 lines, 28 were tested positive for SSR marker Xwmc221 indicating the presence of Lr19/Sr25. Out of 14 selected F4 lines from F3, nine were homozygous positive for Lr19/Sr25. The advanced breeding lines viz., WBM3632 (WBM3697) and WBM3635 were also positive for Lr19/Sr25 with SCAR marker SCS265512. SSR marker Xgwm1 producing 215 bp band in Avst-15, FLW13 and HS661 confirmed the presence of Yr15 . Agronomically, HS661 was comparable with recipient variety HS295 and superior to a standard check HS490 under late sown restricted irrigation production conditions of NHZ. HS661 may serve as a potential donor for creating new usable variability against all the three rusts.

scholarly journals Genetic Analysis of Leaf Rust Resistance in Six Durum Wheat Genotypes

2014 ◽  
Vol 104 (12) ◽  
pp. 1322-1328 ◽  
Author(s):  
Alexander Loladze ◽  
Dhouha Kthiri ◽  
Curtis Pozniak ◽  
Karim Ammar
Keyword(s):  
Durum Wheat ◽  
Leaf Rust ◽  
Resistance Genes ◽  
Rust Resistance ◽  
Durable Resistance ◽  
Puccinia Triticina ◽  
Leaf Rust Resistance ◽  
Adult Plant ◽  
Seedling Resistance ◽  
Allelism Tests

Leaf rust, caused by Puccinia triticina, is one of the main fungal diseases limiting durum wheat production. This study aimed to characterize previously undescribed genes for leaf rust resistance in durum wheat. Six different resistant durum genotypes were crossed to two susceptible International Maize and Wheat Improvement Center (CIMMYT) lines and the resulting F1, F2, and F3 progenies were evaluated for leaf rust reactions in the field and under greenhouse conditions. In addition, allelism tests were conducted. The results of the study indicated that most genotypes carried single effective dominant or recessive seedling resistance genes; the only exception to this was genotype Gaza, which carried one adult plant and one seedling resistance gene. In addition, it was concluded that the resistance genes identified in the current study were neither allelic to LrCamayo or Lr61, nor were they related to Lr3 or Lr14a, the genes that already are either ineffective or are considered to be vulnerable for breeding purposes. A complicated allelic or linkage relationship between the identified genes is discussed. The results of the study will be useful for breeding for durable resistance by creating polygenic complexes.

scholarly journals Adult Plant Resistance in Maize to Northern Leaf Spot Is a Feature of Partial Loss-of-function Alleles ofHm1

2018 ◽  
Author(s):  
Sandeep R. Marla ◽  
Kevin Chu ◽  
Satya Chintamanani ◽  
Dilbag Multani ◽  
Antje Klempien ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Resistance Genes ◽  
Plant Resistance ◽  
Leaf Spot ◽  
Adult Plant Resistance ◽  
Plant Diseases ◽  
Adult Plant ◽  
Hc Toxin ◽  
Differential Transcription

ABSTRACTAdult plant resistance (APR) is an enigmatic phenomenon in which resistance genes are ineffective in protecting seedlings from disease but confer robust resistance at maturity. Maize has multiple cases in which genes confer APR to northern leaf spot, a lethal disease caused byCochliobolus carbonumrace 1 (CCR1). The first identified case of APR in maize is encoded by a hypomorphic allele,Hm1A, at thehm1locus. In contrast, wild type alleles ofhm1provide complete protection at all developmental stages and in every part of the maize plant.Hm1encodes an NADPH-dependent reductase, which inactivates HC-toxin, a key virulence effector of CCR1. Cloning and characterization ofHm1Aruled out differential transcription or translation for its APR phenotype and identified an amino acid substitution that reduced HC-toxin reductase (HCTR) activity. The possibility of a causal relationship between the weak nature ofHm1Aand its APR phenotype was confirmed by the generation of two new APR alleles ofHm1by mutagenesis. The HCTRs encoded by these new APR alleles had undergone relatively conservative missense changes that partially reduced their enzymatic activity similar to HM1A. No difference in accumulation of HCTR was observed between adult and juvenile plants, suggesting that the susceptibility of seedlings derives from a greater need for HCTR activity, not reduced accumulation of the gene product. Conditions and treatments that altered the photosynthetic output of the host had a dramatic effect on resistance imparted by the APR alleles, demonstrating a link between the energetic or metabolic status of the host and disease resistance affected by HC-toxin catabolism by the APR alleles of HCTR.AUTHOR SUMMARYAdult plant resistance (APR) is a phenomenon in which disease resistance genes are able to confer resistance at the adult stages of the plant but somehow fail to do so at the seedling stages. Despite the widespread occurrence of APR in various plant diseases, the mechanism underlying this trait remains obscure. It is not due to the differential transcription of these genes, and here we show that it is also not due to the differential translation or activity of the APR alleles of the maizehm1gene at different stages of development. Using a combination of molecular genetics, biochemistry and physiology, we present multiple lines of evidence that demonstrate that APR is a feature or symptom of weak forms of resistance. While the mature parts of the plant are metabolically robust enough to manifest resistance, seedling tissues are not, leaving them vulnerable to disease. Growth conditions that compromise the photosynthetic output of the plant further deteriorate the ability of the seedlings to protect themselves from pathogens.One sentence summaryCharacterization of adult plant resistance in the maize-CCR1 pathosystem reveals a causal link between weak resistance and APR.

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