Presentation on theme: "1 Genetic Mapping of Powdery Mildew Resistance Genes in Wheat Ainong Shi Advisors: Steven Leath, and Paul Murphy North Carolina State University."— Presentation transcript:
1 Genetic Mapping of Powdery Mildew Resistance Genes in Wheat Ainong Shi Advisors: Steven Leath, and Paul Murphy North Carolina State University
3 Wheat powdery mildew (Blumeria graminis f. sp. tritici) is a disease of major importance. The use of single gene resistance is the primary method of control of this disease. Identification of molecular markers and genetic mapping can provide a tool for marker assisted breeding.
4 l Identify molecular markers l Genetic mapping of genes for powdery mildew resistance in wheat Objective
6 An example Identification and mapping of Pm25 gene for wheat powdery mildew resistance
7 Coker x NC96BGTA5 F 1 x Coker F 2 BC 1 F 1 X Obtaining segregating populations for genetic analysis (S) (R)
8 An example of detached leaf technique for reactions to powdery mildew in a F2 population. The culture dish contains 35 primary leaf segments from 35 F2 plants of a Coker 68-15/NCBGTA5 F2 population and six leaf segments from susceptible Check Chancellor on the each side. Detached leaf technique
9 A scale of 0 to 9 Resistant: 0-3 Intermediate: 4-6 Susceptible: 7-9 Assessment of Reaction to Powdery Mildew
10 Reactions to isolate 209a2 of Bgt in Coker 68-15/NCBGTA5 F 2 and Coker 68-15*2/NCBGTA5 BC 1 F 1 populations Frequency Infection type Res.Sus. Exp. 2 Gene F : Pm25 BC1F155521:10.08 F2
11 Method: Bulked segregant analysis (BSA) Segregating population: Coker 68-15*2/NCBGTA5 BC 1 F 1 R bulked from 30 high resistant plants S bulked from 30 high susceptible plants A total of 156 ten-base random primers Primer Screening
12 Amplification pattern from RAPD marker OPX for Pm25 in four wheat materials: 1. Coker (None), 2. NC96BGTA5 (Pm25), 3. S bulked (None), 4. R bulked (Pm25), An example for BSA
13 Amplification pattern of DNA detecting OPX , OPAG04 950, and OPAI RAPD fragments in the Coker 68-15*2/NC96BGTA5 BC1F1 population. Lane 1 to 5 from susceptible plants and lane 6 to 11 from resistant plants with lane 1 and 7 indicating recombinants.
14 _______________________________________________ Rec Dist Marker Frac cM id Name _______________________________________________ (4)OPAI (4.2%) 4.4 (2)OPX (4.2 %) 4.4 (3)OPAG (11.3 %) 12.8 (1) Pm25 A genetic map of the region carrying Pm25 constructed from the Coker 68-15*2/NC96BGTA5 BC 1 F 1 population
15 Another example Mapping Pm3b gene for resistance to wheat powdery mildew Method: NILs Linkage analysis: F 2 seg.
16 Amplification patterns of DNA from seven ‘Chancellor’ near-isogenic lines with random primers. 1.Chancellor (Cc, recurrent parent), 2.Axminister/8*Cc (Pm1), 3.Ulka/8*Cc (Pm2), 4.Asosan/8*Cc (Pm3a), 5.Chul/8*Cc (Pm3b), 6.Sonora/8*Cc (Pm3c), 7.Khapli/8*Cc (Pm4a) bp OPAN07 A total of 332 random Operon primers were used to screen for RAPD markers in the seven ‘Chancellor’ near-isogenic lines.
17 Chancellor//Chul/8*Cc F 2 IsolateRes.Sus.Exp. 2 E : Infection type Frequency
18 Amplification pattern of DNA detecting OPAN RAPD fragments from the F 2 population of Chancellor//Chul/8*Cc. P S =susceptible parent, P R =resistant parent, S=Susceptible individual in the F 2 and R=resistant individual in the F 2. Lane M is a 1-kb molecular-weight marker. 1400bp
19 Co-segregation of reaction of Pm3b to E 3 14 isolate of Bgt and RAPD marker OPAN in the Chancellor/(Chul/8*Cc) F 2 population. ________________________________________________________ Locus Phenotype 2 A 2 B 2 AB Recombination A B RM* Rm SM Sm (3:1)(3:1) (9:3:3:1) fraction Pm3bAN ** 1.2 ________________________________________________________ * RM = resistant plant with the marker, Rm = resistant without the marker, SM = susceptible with the marker, and Sm = susceptible without the maker.
23 _______________________________________________ Rec Dist Marker Frac cM id Name _______________________________________________ (4)OPAI (4.2%) 4.4 (2)OPX (4.2 %) 4.4 (3)OPAG (11.3 %) 12.8 (1) Pm25 A genetic map of the region carrying Pm25 constructed from the NK-68-15*2/NC96BGTA5 BC 1 F 1 population