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Yellow rust seminar by Priyanka (Phd Scholar Genetics and Plant Breeding CSK HPKV Palampur)
- 1. Yellow Rust In Wheat: Genetics And Management Presented by : Priyanka Ph.D. II year (A-2019-40-018) CSK HPKV, Palampur Credit Seminar
- 2. INTRODUCTION A major staple food at global level and occupies about 21.8 % of total cultivated area Factors affecting destabilization of wheat yields BIOTIC FACTORS ABIOTIC FACTORS Affected by a number of pathogens causing disease out of which the rust pathogens are very important.
- 3. Rust Pathogen Nomenclature Puccinia recondita f. sp. tritici The pathogen of leaf rust; also known as brown rust Puccinia striiformis f. sp. tritici The pathogen of stripe rust; also known as yellow rust. Puccinia recondita f. sp. tritici The pathogen of leaf rust, also known as brown rust
- 4. Dr. K.C. Mehta’s Classical Work Yellow rust Source: North west Himalayas Target: North India NILGIRIS Black rust Source: Nilgiris Target: Peninsular India Brown rust Source: Nilgiris and Nepal Target: Entire wheat area
- 5. Dissemination of the three rusts from foci of infection Joshi et al. 1985
- 6. WHAT IS YELLOW RUST CAUSAL ORGANISM Puccinia striiformis f. sp. tritici Globally significant disease Disease of cooler climate (2°C - 15°C) Crop damages can reach 50 – 100%
- 7. SYSTEMATIC POSITION Kingdom: Fungi Phylum: Basidiomycota Class: Urediniomycetes Subclass: Incertaesedis Order: Uredinales Family: Pucciniaceae Genus: Puccinia Species: P. striiformis f.sp.tritici
- 8. HISTORY Gadd (1777) Yellow Rust mentioned for the first time Schimdt (1827) Described the pathogen infecting barley glumes as Uredoglumarum Westend (1854) Named the pathogen as Puccinia striiaeformis (with reference from rye). Fuckel (1860) Named it as Puccinia staminis Eriksson & Henning (1894) Yellow rust as Puccinia glumarum. The term was reviewed again in 1953 and was changed to specials of Puccinia striiformis
- 9. Pathogen Characters Yellow Rust is considered to be an obligate parasite. The fungus produces bright yellow to orange uredospores 20 to 30 µm in diameter. These spores have thick and echinulated walls and are contained in sori or pustules on the plant . Uredospore production usually is followed by teliospore production late in the growing season. Earlier, no alternate hosts were known. But now it has been found that alternate hosts are barberry (Berberis chinensis, B. koreana, B. holstii, B. vulgaris, B. shensiana, B. potaninii, B. dolichobotrys etc.)
- 10. Symptoms And Spore Morphology
- 11. LIFE CYCLE
- 12. Rust Score Guidelines HOST RESPONSE AND INFECTION TYPE DESCRIPTIONS USED IN THE WHEAT STRIPE RUST SYSTEM
- 13. Rust Score Guidelines MODIFIED COBB’S SCALE The modified Cobb scale: (A) Actual percentage occupied by rust uredinia; (B) Rust severities of the modified Cobb scale (Peterson et al., 1948)
- 14. Predominant Pathotypes of Wheat Rusts in India Area Black Brown Yellow Nilgiri hills 40A 77-9,77-5 I Peninsular India 11 104-2,77-9 – Central India 40A 104-2,77-9,77-5 – Eastern India 21A-2 77-5 – Northern India 21-1, 21A-2 77-5,104-2 46S119,110S119,46S 117,238S119 Regional Station, Shimla-ICAR, IIWBR
- 15. GENETICS OF RUST RESISTANCE IN WHEAT • Biffen (1905) first demonstrated that resistance to stripe rust in wheat follows Mendel’s laws, the genetics of resistance to stripe rust has been studied for a century. • Studies conducted worldwide on the genetics of rust resistance in wheat • Many insights gained into the structure and functional aspects of the genetic architecture of rust resistance in wheat • A total of 60 Sr, 79 Lr and 82 Yr genes designated • Many temporarily designated and undesignated resistance genes and QTLs have been indicated in many studies
- 16. TYPES OF RESISTANCE Sr.NO WAYS OF SEPERATION RESISTANT TYPE (I) RESISTANT TYPE (II) 1. Growth Stage All-stage resistance (ASR) Adult Plant Resistance (APR) 2. Specificity Vertical Resistance Horizontal Resistance 3. Degree Of Resistance Complete Resistance Incomplete Resistance 4. Speed Of Symptoms Development Fast Rusting (super susceptible/no resistance) Slow rusting 5. Response to Temperature Temperatures non sensitive Temperature sensitive 6. Inheritance Qualitative resistance Quantitative resistance 7. Effect of genes Major gene resistance Minor gene resistance 8. Number of genes Monogenic resistance Polygenic resistance 9. Molecular basis NBS-LRR type resistance Non NBS-LRR type 10. Durability Non durable Durable 11. Race-specificity, growth stage and temperature sensitivity Race-specific all-stage resistance Non-race specific high- temperature adult-plant (HTAP) resistance
- 17. DURABLE RESISTANCE Resistance which has remained effective in a cultivar during its widespread cultivation for a long sequence of generations or period of time in an environment favorable to a disease or pest (Johnson 1988). A combination of several genes may confer durability of resistance on the premise that components such as increased latent period, smaller pustule size, reduced number of uredia per unit area etc. may contribute towards slow development of rust
- 18. Linkage Between Rust Resistance Genes A number of rust resistance genes show linkage, which offers an added advantage towards multiple rust resistance breeding in wheat. The linked genes for rust resistance in wheat: Sr2/Lr27/Yr30 Sr15/Lr20 Sr23/Lr16 Sr24/Lr24/Yr71 Sr25/Lr19 Sr31/Lr26/Yr9 Sr38/Lr37/Yr17 Sr39/Lr35 Lr57/Yr40 Lr62/Yr42 Lr76/Yr70 Lr25/Lr18 Yr51/Yr60 Tomar et al. 2014
- 20. SLOW RUST RESISTANCE A type of resistance where disease progresses at retarded rate, resulting in intermediate to low disease levels against all races of pathogen (Caldwell 1968). The purpose of slow rusting or partial resistant is to achieve durable resistant and provide a sustainable approach of disease control Numbers of slow rusting gene have been identified so far. However, the known slow rusting genes which present in number of CIMMYT release germplasm line or cultivars are Lr34 and Lr46 present in combination with other minor gene (Bai et al., 1999).
- 21. Expression Of Resistance Gene interactions: • Epistasis is generally observes when 2 or more resistant genes are present together i.e. the gene conditioning the lowest infection type or highest level of resistance is expressed • Additive effects: Additive interactions for resistance to leaf and stripe rust among Lr46, Yr29 and 3-4 QTL’s in RIL’s derived from Avocet × Kundan Yr 81 interacted with Yr 18 towards enhanced stripe rust resistance Yr 82 interacted with Yr 29 to produce lower adult plant response to stripe rust
- 22. Expression Of Resistance • Complementary effects The Yr17 resistance in Avocet R conditioned by two complementary genes, Yr 73 on 3DL and Yr 74 on 5BL • Suppressor effects A Yr 18 suppressor was reported in four Chinese Landraces
- 23. Pleiotropic effect of Resistant genes • Changes in two critical amino acids in the resistant allele of Yr46/Lr67 result in encoding a protein that has lost hexose transport function and could therefore disturb the balance of sugars between the extracellular and intracellular spaces of the leaf. This may reduce the availability of nutrients inside the host cell, hence the effectiveness of this gene against multiple biotrophic fungi. Alternatively, altering apoplastic sugar concentration may induce activities of defense responses • The gene Lr34/Yr18 has been shown to encode an ATP binding Cassette (ABC) transporter. However, the basis of resistance and the substances of this ABC transporter are yet unknown.
- 24. PAPR Genes • Lr 34/ Yr 18/ Sr57/Pm38/Sb1/Bdv1/Ltn1 (7DS) • Lr 46/ Yr 29/ Sr 58/Pm 39/ Ltn 2 (1BL) • Lr 67/ Yr 46/ Sr 55/ Pm 46/ Ltn 3 (4 DL)
- 25. Effectiveness of PAPR Genes • Although PAPR genes are widely effective, the level of resistance imparted by them on their own under heavy disease pressure is not adequate and need to be complemented by other resistance genes • Their expression is significantly influenced by the environmental conditions.
- 26. MECHANISM OF RUST RESISTANCE Periyannan et al. 2017
- 28. Cataloged genes conferring resistance to Puccinia striiformis f.sp.tritici in wheat
- 29. Cataloged genes conferring resistance to Puccinia striiformis f.sp.tritici in wheat Park et al. 2016
- 30. RESISTANCE GENES TRANSFERRED FROM OTHER TRITICUM spp. AND WILD RELATIVES Source Rust resistance genes T. dicoccoides Lr 33, Lr 64, Yr 13, Yr 35, Yr 36 T. spelta Lr 44, Lr 65, Lr 71, Yr 5 T. Turgidum ssp. dicoccum Sr2, Sr9d, Sr9e, Lr 14a, Yr 15 T. Turgidum ssp. durum Yr 7, Yr 24, Yr 53, Yr 56 Aegilops caudata Sr 34, Yr 8 Aegilops geniculata Sr 53, Lr 57, Yr 40 Aegilops kotschyi Lr 54, Yr 37 Aegilops neglecta Lr 62, Yr 42 Aegilops squarossa Lr 40, Lr 41, Lr 42, Sr 33, Sr 43,Yr 28 Aegilops umbellulata Lr 9, Lr 76, Yr 70 Aegilops ventricosa Lr 37, Yr 17 Thinopyrum intermedium Sr 44, Yr 50
- 31. Effective ways to fight rusts in India • Survey and surveillance in mediterranean areas on our own or with international collaboration • Understanding of evolution of biotypes in races • Durable resistance genes combating threat of new races
- 32. Methods of Controlling the Rust Diseases Roelfs et al. 1992
- 33. Gene Pyramiding Gene pyramiding defined as the method aimed at assembling multiple desirable genes from multiple parents into a single genotype. The end product of a gene pyramiding program is a genotype with all of the target genes. Watson and Singh (1953) first introduced the concept called gene pyramiding
- 34. Different schemes of Backcrossing for Gene Pyramiding Stepwise gene transfer Simultaneous gene transfer Stepwise and simultaneous gene transfer Joshi and Nayak 2010
- 35. GENETIC STOCKS WITH PYRAMIDED RUST RESISTANCE Bhardwaj et al. 2019
- 36. GENE DEPLOYMENT The development and deployment of resistant wheat varieties has proven to be the most economic, effective and efficient means of managing rust diseases. Gene deployment is a promising and effective strategy to curtail the rust epidemics. Stripe rust resistance gene Yr9 provided resistance for a very long period in India but now has become ineffective due to evolution of new virulences. Deployment of genes such as Yr2, Yr 18 , Yr 29 and Yr46, which are individually as well as collectively effective against the prevailing races would be an appropriate strategy to check the losses due to stripe rust. A combination of all stage (seedling) resistance, slow rusting resistance, and APR of both the race specific and non-race specific types is deployed for the Agronomy 2019, 9, 892 9 of 14 strategic management of wheat rusts Tomar et al. 2014
- 37. Multilines • Jensen(1952) gave the concept of mutilines • Borlaug (1953) used an equivalent term ‘composite’ and proposed as a new approach for resistance to stem rust of wheat (Puccinia graminis tritici) Sonalika Multilines MLSKA-9 (6 isogeni lines) MLSKA-12 (9 isogenic lines) Sonalika Multiline-1 (6 components) First commercial multiline Miramar 63 Miramar 65 Kalyan Sona Multilines KSML 3(6 components) KML 7406 or Bithoor (9 components) MLKS 11 (8 components) Yaqui type multiline developed but could not be release due to availability of semi dwarf wheats Tumult based on 7 resistance sources against yellow rust released in Netherlands
- 38. CHEMICAL CONTROL If the yellow rust is noticed in the wheat crop, it is advised to spray the crop with Propiconazole (Tilt) 25 EC @ 0.1 % (1 ml / litre) using power sprayer or tractor mounted boom sprayers. 0.5 litre per hectare of the fungicide shall be sufficient to effectively cover the wheat crop. Source: Directorate of Wheat Research, Karnal Use of chemicals for rust control dates back to year 1900. Sulphur had been a widely recommended chemical Good control of wheat rusts can be achieved with commercially available fungicides and proper application timing. Post-infection application of nickel salts were found effective in rust control in 1958 and in 1963 commercial control of Puccinia striiformis with nickel fungicides was reported
- 39. CASE STUDIES
- 40. • Materials and Methods :
- 41. • Results : Randhawa et al. 2019
- 43. • Materials and Methods : In this study, 70 publically available molecular markers were used to identify the distribution of 35 Yr genes in 68 wheat genotypes. Out of 35 Yr genes, 25 genes amplified the loci associated with Yr genes. Of the 35, 18 were all-stage resistance ASR (All- stage resistance) genes and 7 (Yr16, Yr18, Yr29, Yr30, Yr36, Yr46 & Yr59) were APR (Adult-plant resistance) genes . • Results : At the adult-plant stage, disease data on infection types and severity was recorded. Fifty-three genotypes were found resistant (accounting for 77.94% of total genotypes, 3 genotypes (4.4%) showed trace resistance, 7 genotypes (10.3%) were moderately susceptible (ITs 3) and 5 genotypes (7.35%) including infector (WH 711 and PBW 343) were susceptible. Overall 60 genotypes expressed yellow rust resistance under field conditions against predominant yellow rust pathotypes i.e. 46S119, 110S119, 110S84 &78S84. Marker assisted detection of 35 Yr genes in wheat genotypes was carried out using 70 Yr gene linked markers. The results indicated the effectiveness of these markers for specific Yr gene which also identified the resistant lines containing multiple Yr genes. Rani et al. 2019
- 44. Contribution of All stage resistant genes (ASR) and Adult Plant Resistant genes (APR) in wheat genotypes Rani et al. 2019
- 45. CONCLUSION The ever changing nature of wheat leaf, stripe and stem rusts poses a serious threat to future wheat production. As an emergent tool for managing wheat rusts in India, fungicides belonging to triazole (Propiconazole, Tebuconazole, Triadimefon), are kept ready for effectively controlling wheat rusts at the rate of 0.1 percent. However, resistant cultivars have remained popular among the farmers as they are cost effective and environmentally neutral in terms of impact. The emergence of new races of rusts require continued efforts to deploy new resistance genes.
- 46. CONCLUSION This collective effort in developing resistant cultivars and understanding disease epidemiology has gradually reduced the magnitude and frequency of epidemics. The claim is well verified with the fact that India has had no wheat rust epidemic for the last 47 years even when many countries in the world have had rust outbreaks. Rapid advances in molecular marker technologies are revolutionizing the ways in which resistance can be manipulated in breeding programmes. A number of rust resistant genes are still effective in different regions of the world. Such genes need to be utilized in wheat crop improvement in planned and judicious manner