1 / 21

Ogallala Aquifer Program Workshop March 5, 2013 Amarillo, TX

“Production and Field Testing of Transgenic Cotton that Expresses Transcription Factors for Enhanced Seed Traits and Productivity Under Drought Stress”. Ogallala Aquifer Program Workshop March 5, 2013 Amarillo, TX. Chris Rock, Aman Mittal , Biological Sciences, TTU John Burke

palani
Download Presentation

Ogallala Aquifer Program Workshop March 5, 2013 Amarillo, TX

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. “Production and Field Testing of Transgenic Cotton that Expresses Transcription Factors for Enhanced Seed Traits and Productivity Under Drought Stress” Ogallala Aquifer Program WorkshopMarch 5, 2013 Amarillo, TX • Chris Rock, Aman Mittal, • Biological Sciences, TTU • John Burke • USDA Plant Stress & • Germplasm Lab, Lubbock • Glen Ritchie • Plant & Soils, TTU

  2. ABA Signal Transduction: why is it important? Viviparous1 encodes a B3 domain TF1 • Abscisic acid (ABA) controls stress-related responses in all higher plants. • Promotesseedmaturation • and dormancy (desiccation) • Modulates water use efficiency • via stomatal aperture • Overlaps/interacts with other • stress pathways (e.g. cold, salt, UV and pathogens) • ABA regulates cell wall metabolism4 (fiber?), root meristem division/expansion5 and leaf development6 and interacts with other hormones and sugar signaling (source/sink for fiber?) abaand abimutants are “wilty”2,3 • McCarty et al. (1991) Cell 66: 895 • Finkelstein and Rock (2002) “The Arabidopsis Book” • Rock and Ng (1999) Amer. J. Bot. 86: 1796 • Subramanian et al. (2002) Plant Mol Biol49: 93 • Finkelstein et al. (2005) Plant Mol Biol 59: 253 • Barrero et al. (2005) J. Exper. Bot56: 2071

  3. RELATED TO ABI3/VP1 (RAV2) functions as a positive effector of ABA-inducible gene expression and synergizes with bZIP transcription factors ABI5 and ABF3 Electroporation proUbi:LUC+ proEm:GUS+ proUbi:Effector protoplast Overnight incubation + 100 μM ABA No ABA U.S. Patent #7,446,241 C. D. Rock and S. S. L. Gampala

  4. Transgenic Cotton manifests drought avoidance characters and RAV1/2 +ABI5 “stacked” lines show synergistic effect on root biomass • pro35S:RAV1, :RAV2, :RAV2-Like and ABI5 Cotton • 90 days of deficit watering in green house also showed: • Longer Internodes in RAV1/2 and RAV1/2 X ABI5 (~20%) • more fruit mass in ABI5 and RAV1/2 X ABI5 (~15%) RAV2 X ABI5 Weekly drought spells for 90 days First Drought Spell (11 Days of no watering) RAV2 X ABI5 RAV2 ABI5 Coker 312 Coker 312

  5. RAV2 and RAV1 overexpression resulted in delayed flowering in unstressed and drought conditions in the field, which carries over to stacked ABI5 lines

  6. RAV1 and RAV2 over-expression represses GossypiumhirsutumFlowering Locus T homologue transcript RAV2 (aka TEMPRANILLO2) regulates flowering time in Arabidopsis via direct repression of the “florigen” gene FLOWERING LOCUS T (FT). Castillejo and Pelaz, 2008. Curr Biol. 18: 1338 RAV1 overexpression also delays flowering in Arabidopsis. Hu et al. 2004. Cell Res 14: 8

  7. 2012 New Deal Farm 2 acre Field Trial (11/3/12) Random block design, 40’ zones, triplicate samples incl UA48 and Arcot8712 checks Deficit 16 rows Well-watered 16 rows Dryland 16 rows

  8. RAV1, RAV2, and ABI5 cotton maintained higher water use efficiency over an extended time – under deficit irrigation conditions Reduced Stomatal Conductance In transgenicsunder deficit irrigation is major factor for increased water use efficiency.

  9. HVI and AFIS measurements onidentical samples shows that drought affects wild type fiber length more, and droughtedtransgenics have longer fibers than irrigated wild type RAV1.3ir RAV2.4ir RAV1.3dr RAV2.24dr

  10. RAV1 and RAV2 cotton have longer fiber under different watering regimes, especially at higher nodes 20% 65% yield reduction 43% yield reduction (-5.3%, p=0.02) (-8.3%, p=0.007) (-7.1%, p=0.002)

  11. Field trial of transgenics against the “Gold Standard” UA48 • Bourland F, DC Jones (2012) Registration of 'UA48' Cotton Cultivar. J Plant Registr 6: 15

  12. WW RAV1 and -2 transgenics had stronger, more elastic yarn that is more uniform and has fewer ‘neps’ (thick and thin spots) droughted NOTE failure to spin droughtedwild type lint, due to insufficient length

  13. Premiums for gain (~7%) in fiber length do not make up for losses (~12%) due to drought yield penalty, but still can add ~$50m/yr value to west Texas fiber, e.g. introgress into elite varieties

  14. RAV1 and RAV2 overexpression enhances the expression of GhMYB25and GhMYB25-Like: key effectors of ovule fiber development E. Dennis lab: Machado et al. (2009) Plant J. 59:52 Relative Expression Normalized to HistoneH3 Walfordet al. (2011) Plant J. 65:785 Stages of Ovule and fiber development

  15. A downstream marker of fiber elongation, MYB2, is elevated in transgenics, as is endogenous GhRAV Up regulation of GhRAV by AtRAVs: feedback loop? microRNA828 Up regulation of GhRAV by drought Relative Expression Normalized to HistoneH3 Wang et al (2004) Plant Cell 16:2323 Stages of Ovule and fiber development

  16. Summary points • At-RAV and At-ABI5 over-expression in cotton leads to improved root growth and improved water use efficiency under deficit irrigation conditions • Stacking ABI5 with RAV1/2 synergizes drought avoidance trait • AtRAV1 and AtRAV2 repression of FT homologue in cotton leads to increased vegetative growth phase resulting in elongation of fiber, probably due more photosynthate relayed into strong sink (developing ovules and elongating fiber). • Longer fiber in RAV1 and RAV2 cotton is may be a result of increased expression of known MYB effectors of initiation and elongation in ovules. • Longer fiber in RAV1 and RAV2 translates to real world improved yarn characteristics

  17. Acknowledgements Students: Amandeep Mittal (Ph.D. 10/12) Fan Jia (Ph.D. 5/12) Nevin Jiang, Sayani Mallick Qingjun Luo (Ph.D. 10/10),H-L Zhu Fangqian Ou-Yang (M.Sc. 8/11) Collaborators: Glen Ritchie, Plant & Soils TTU John Burke, USDA-ARS Lubbock Paxton Payton, USDA-ARS Lubb Funding: Texas State Support Cmte, Cotton Inc. USDA Ogalalla Aquifer Initiative special thanks: Tyler Painter, Craig Bednarz, Eric Hequet,Jane Dever, Fred Bourland, Tom Brooks TTU Fiber & Biopolymer Institute

  18. RAV1 and RAV2 transgenics show node shift in fruit retention map– more pronouced in response to drought Well Watered Deficit Irrigation 1 0.8 0.6 0.4 0.2 0.0 Average Fraction of bolls retained/node

  19. Higher expression of Glutathione S-Transferase oxidative stress response marker might help in drought recovery by reducing free radicals 1.89 2.53 1 Longer fiber, longer internodes in deficit irrigation, delayed flowering, boll retention at higher nodes in drought stress, extended lateral root ----- “Less stressed phenotype”? HovavR et al. (2008) The evolution of spinnable cotton fiber entailed prolonged development and a novel metabolism. PLoS Genet 4:e25.

  20. Relative Expression Normalized to Histone 3 Wendel group - Hovav et al (2008) Plos Genet. 4, 2 e25 Stages of Ovule and fiber development

  21. Fiber length penalty in response to drought (~4/32nds) is less than length gains by transgenics Dry-Land Well Watered Per Cent of Total Fiber Wild Type RAV2 41-24-8-1 Fiber Length [W] in

More Related