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Interactions with Hosts and Pathogens -a history of close calls-. Clint Magill Professor of Genetics Department of Plant Pathology & Microbiology Texas A&M University. 4N maize X 4N sorghum . ‘Rescued’ embryos. Pathogen Variability. Anthracnose of Sorghum. 18 isolates. 17 pathotypes.
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Interactions with Hosts and Pathogens-a history of close calls- Clint Magill Professor of Genetics Department of Plant Pathology & Microbiology Texas A&M University
4N maize X 4N sorghum • ‘Rescued’ embryos
Pathogen Variability Anthracnose of Sorghum 18 isolates 17 pathotypes Louis Prom & RamasamyPerumal
Complementing di-auxotrophsPyriculariaoryzae leu-, ade- lys-, met- nic-, ura- buf, lys- Dennis Genovesi
1N and 2N conidia Parasexual origin of new pathotypes?
Anther Culture and Rice Chloroplast DNA ChantelScheuring
Aberrant Ct DNA in Albinos Green Albino Albino Green Alberto Livore
Pathogenic Race Changes BaiChai Wu
Phymatotrichumomnivorum grapes Cotton root rot fruit trees (pear)
DNA methylation in P. omnivorum P. omnivorumgrew in 5AZA C; the sclerotia that formed had no 5mC and did not germinate Jane Magill, Eldon Jupe
Pathogen-induced host defense -mRNA Oscar Joost, Al Bell, Bob Stipanovic
CVVK CVVK HMGR CoA-reductase (first step in terpenoidphytoalexin synthesis)
Sorghum Defense Responses (PAL is the first step in flavonoid phytoalexin biosynthesis) Cory Cui
Grain mold/Curvularia & Fusarium Chris Little, SeribaKatilé
AFP mRNA levels in sorghum glumes 48 h post inoculation withCurvularia lunata (CL), Fusarium thapsinum (FT), water (control) or both CL+FT. RTx430SC170SurenoTX2911
RTx430SC170SurenoTX2911 PR10 mRNA levels in glumes 48h p.i.
P. sorghi • conidia-asexual spores • antheridum and oogonium forming in leaf tissue
Downy mildews of Andropogonea • Peronosclerospora sorghi • P. maydis • P. sacchari • P. philippinensis(select agent) • P. zeae • Sclerophthorarayssiae(select agent) • Sclerospora graminicola
Dot-Blot Hybridizations; probe pMLY12 Colletotrichm graminicola P. sorghi Infected seed, with glume Acremonium strictum Healthy seed, with glume Fusarium moniliforme Infected seed, no glume Infected seed, glumes 40d Healthy seed, no glume Infected seed, no glumes 40d Chenglin Yao
P. sorghi Thai1 P. sorghi Thai2 P. sorghi Thai1 P. sorghi Thai2 P. sorghi pt1 P. sorghi pt1 P. sacchari P. sacchari P. maydis P. maydis M M ITS 1 ITS 2 & 5.8s PCR using conserved ITS primers
Nebulize genomic DNA with HaeIII, RsaI, and DraI+ 50 ng of RNaseA 2. Ligate adapters AP11 (5´CTCTTGCTTAGATCTGGACTA3´) & AP12 (5´pTAGTCCAGATCTAAGCAAGAGCACA3´, where p = 5´ phosphate) 3. Amplify by PCR using AP11 primer 9.Cloning, Squencing, Identifying SSRs, Primer Designing & Pathotypes genotyping Microsatellite Capture SSR’s for DM 4. Hybridize with di & tri biotinylated oligos (TG/AC, CA/GT, GA/CT, CAA, AGG and GTT) 8. Amplify by PCR using AP11 primer 6. Elution Of captured DNA 5.Select with streptavidin-coated paramagnetic beads 7. Remove residual oligos
Cluster analysis of DM species based on 54 Simple Sequence Repeats RamasamyPerumal
R gene tagging Sorghum anthracnose example Midrib infection Stem infection Seed infection
Co-segregation of AFLP marker Xtxa6227 and the Cg1 locus in F2-3 progeny derived from the cross of BTx623 and SC748-5. AFLP templates from parental inbreds BTx623 (cg1cg1) and SC748-5 (Cg1Cg1) and IS3620C (mapping parent) were run as controls to aid in the identification of polymorphic bands. Co-segregation of dominant SSR marker SSR 1 and the cgf1 locus in F2-3 progeny derived from the cross of ATx623 and SC748-5. Genomic DNA from parental inbreds BTx623 (cg1cg1) and SC748-5 (Cg1Cg1) were run to aid in the identification of parental alleles for SSR 1. The amplified band from the SSR 1allele was 152 bp (BTx623) or 155 bp (SC748-5) RamasamyPerumal
RNAi against cotton nematodes Root-Knot reniform
Two species causing large losses in Texas • Root knot = Meloidogyne incognita • Reniform = Rotylenchulusreniformis • Plan • ID ‘matching’ sequences in genes of both species that are lethal if knocked out in C. elegans • Prepare hairpin construct to express in cotton • a) roots • b) constitutively (CaMV 35S promoter) • So far • No common sequences, but individual constructs made • Transient expression in root cultures worked well • Transgenic plants look very promising KeertiRathore and Jim Starr
THANKS To you for listening and to TRRF Several USDA Collaborative Agreements INTSORMIL TARP The Sorghum Checkoff Program Global Crop Diversity Trust Texas A&M Agrilife Research (formerly TAES) For Research $$