IN INOCULANTS Nodulaid - 17th International Nitrogen Fixation ...
IN INOCULANTS Nodulaid - 17th International Nitrogen Fixation ... IN INOCULANTS Nodulaid - 17th International Nitrogen Fixation ...
17 th International Congress on Nitrogen Fixation Fremantle, Western Australia 27 November – 1 December 2011 Session Details: Tuesday 29 November 2011 Plenary Session 4 1330 - 1500 Authors: Michael Udvardi 1 , Catalina Pislariu 1 , Igor Kryvoruchko 1 , Senjuti Sinharoy 1 , Mingyi Wang 1 , Rajasekhara R. Duvvuru Muni 1 , Ivone Torres-Jerez 1 , Mark Taylor 1 , Shulan Zhang 1 , Xiaofei Cheng 1 , Jiangqi Wen 1 , Ji He 1 , Xinbin Dai 1 , Patrick X Zhao 1 , Yuhong Tang 1 , Rujin Chen 1 , Kirankumar Mysore 1 , Pascal Ratet 2 , Vagner A Benedito 3 , Giles Oldroyd 4 , and Jeremy D Murray 4 1 Samuel Roberts Noble Foundation, Ardmore, OK, USA; 2 ISV-CNRS, Gif sur Yvette, France; 3 West Virginia University, USA; 4 John Innes Centre, Norwich, UK; Presentation Title: Functional genomics of symbiotic nitrogen fixation in legumes Presentation Time: 1400 – 1430 The past few years have seen tremendous development of tools and resources for functional genomics in legumes, including completion or near-completion of several legume genomes, comprehensive gene expression databases for model and crop species, and production of near-saturating mutant populations for efficient forward and reverse-genetic studies of gene function. This presentation will highlight some of these advances in various legumes species before focusing on resource development in the model species, Medicago truncatula and how these resources are accelerating research on symbiotic nitrogen fixation. Phenotypic screening of several mutant populations of Medicago followed by map-based and other cloning approaches have identified several genes that are required for nodule development, differentiation, and/or symbiotic nitrogen fixation (SNF). However, it is clear from transcriptomic studies that hundreds, if not thousands of plant genes are involved in SNF. Anticipating the completion of the Medicago genome sequence, we invested heavily in the development of tools and resources that will enable us and others to decipher the functions of many Medicago genes in the coming years. These resources include a gene expression atlas/database that can be used to obtain developmental and other types of expression data for most Medicago genes, and two large mutant populations, a fast-neutron-bombardment-deletion and a tobacco retro-transposonTnt1-insertion population, which can be used for both forward and high-throughput reverse genetics. About 20,000 Tnt1 insertion lines have been generated in the R108 genotype and phenotypic screens of about half of the population revealed 172 lines defective in SNF. These were sorted into six distinct phenotypic categories. Thermal Asymmetric InterLaced PCR (TAIL-PCR) was used to generate 2,422 flanking sequence tags (FSTs) from these SNF mutant lines. FST analysis identified 33 insertion alleles of the following essential symbiotic genes: DMI1,2,3; NSP1,2; ERN1; NIN; LYK3; FLOT1,2; ENOD40; SYMREM1; and SUNN. High-throughput 454 sequencing using a 2D-pooling strategy is being used to accelerate our current FST sequencing efforts. This will lead to a comprehensive FST database for all Tnt1 insertion lines. In parallel, a PCR-based reverse-screening strategy was established to identify Tnt1 insertions in specific genes of interest. As a result, we have identified additional insertion alleles of known, essential symbiosis genes. The mutant resources and gene expression atlas have also been used to identify novel symbiotic genes, including VAPYRIN, which is required for intracellular accommodation of rhizobia in nodules and of arbuscular mycorrhizal fungi in root cells. Reversegenetics, using the Tnt1-insertion population is currently being used to identify and characterize transcription factors and transporters with essential roles in SNF. This work was supported by the National Science Foundation, the USDA CSREES-NRI, and the Samuel Roberts Noble Foundation. 50 2011
17 th International Congress on Nitrogen Fixation Fremantle, Western Australia 27 November – 1 December 2011 Session Details: Tuesday 29 November 2011 Plenary Session 4 1330 - 1500 Authors: Simon Kelly 1,2 , Yasuyuki Kawaharada 2,3 , Artur Muszynski4, Andree Hubber 1,2 , John Sullivan 1,2 , Niels Sandal 2,3 , Russell Carlson 4 , Jens Stougaard 2,3, and Clive Ronson 1,2. 1 Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand 2 Centre for Carbohydrate Recognition and Signalling, University of Aarhus, Aarhus, Denmark 3 Department of Molecular Biology, University of Aarhus, Aarhus, Denmark 4 Complex Carbohydrate Research Center, University of Georgia, Athens, USA Presentation Title: The requirement for exopolysaccharide in the Mesorhizobium-Lotus symbiosis Presentation Time: 1430 – 1500 To investigate the requirement for exopolysaccharide (EPS) in the formation of determinate nodules on Lotus species, Mesorhizobium loti strain R7A mutants affected in early (exoA, exoB) or mid/late-stages (exoO, exoU, exoK, mlr5265 and mlr5266) of the EPS biosynthetic pathway were isolated. Elution profiles of EPS extracts showed that R7A produced both HMW and LMW fractions of EPS whilst mutant strains produced only a LMW fraction. Early-stage affected mutants formed nitrogen-fixing nodules on L. japonicus cv. Gifu at rates comparable to wild-type R7A, whereas the mid/late-stage mutants formed uninfected nodule primordia, a few of which developed into nodules following a lengthy delay. Examination of the symbiotic proficiency of the exoU mutant on various L. japonicus ecotypes and under differing environmental conditions revealed host and environment interactions in the requirement for EPS. Analysis of fluorescent protein-tagged strains revealed that the ineffective mutants were disrupted at the stage of infection thread (IT) development. Symbiotically-defective EPS and Nod factor mutants functionally complemented each other in co-inoculation experiments. The majority of full-length ITs observed harboured only the EPS mutant strain and did not show bacterial release, whereas all nitrogen-fixing nodules contained both mutants. These results suggest that EPS is required at both the stages of IT initiation and bacterial release and reveal a complex role and requirement for M. loti EPS in determinate nodule formation. These and other results also suggest that EPS plays a signalling rather than structural role in the symbiosis. To identify the putative EPS receptor and the downstream signalling pathway, we have carried out a screen for plant suppressor mutants that form nodules with the exoU mutant. Progress towards the characterisation of these mutants will be presented. 51 2011
- Page 1 and 2: PrinciPal SPonSor: SPonSorS: Progra
- Page 3 and 4: INVENTING THE FUTURE IN INOCULANTS
- Page 5 and 6: 17 ICNF Organising Committee Graham
- Page 7 and 8: Cottesloe Beach © Tourism Western
- Page 9 and 10: GeNeRAl INfoRmATIoN aTM’s Automat
- Page 11 and 12: 16:30 - 16:50 Felix Dakora Tshwane
- Page 14 and 15: Thursday 1 December 2011 08:00 - 12
- Page 16 and 17: 17 th International Congress on Nit
- Page 18 and 19: 17 th International Congress on Nit
- Page 20 and 21: 17 th International Congress on Nit
- Page 22 and 23: 17 th International Congress on Nit
- Page 24 and 25: 17 th International Congress on Nit
- Page 26 and 27: 17 th International Congress on Nit
- Page 28 and 29: 17 th International Congress on Nit
- Page 30 and 31: 17 th International Congress on Nit
- Page 32 and 33: 17 th International Congress on Nit
- Page 34 and 35: 17 th International Congress on Nit
- Page 36 and 37: 17 th International Congress on Nit
- Page 38 and 39: 17 th International Congress on Nit
- Page 40 and 41: 17 th International Congress on Nit
- Page 42 and 43: 17 th International Congress on Nit
- Page 44 and 45: 17 th International Congress on Nit
- Page 46 and 47: 17 th International Congress on Nit
- Page 48 and 49: 17 th International Congress on Nit
- Page 52 and 53: 17 th International Congress on Nit
- Page 54 and 55: 17 th International Congress on Nit
- Page 56 and 57: 17 th International Congress on Nit
- Page 58 and 59: 17 th International Congress on Nit
- Page 60 and 61: 17 th International Congress on Nit
- Page 62 and 63: 17 th International Congress on Nit
- Page 64 and 65: 17 th International Congress on Nit
- Page 66 and 67: 17 th International Congress on Nit
- Page 68 and 69: 17 th International Congress on Nit
- Page 70 and 71: 17 th International Congress on Nit
- Page 72 and 73: 17 th International Congress on Nit
- Page 74 and 75: 17 th International Congress on Nit
- Page 76 and 77: 17 th International Congress on Nit
- Page 78 and 79: 17 th International Congress on Nit
- Page 80 and 81: 17 th International Congress on Nit
- Page 82 and 83: 17 th International Congress on Nit
- Page 84 and 85: 17 th International Congress on Nit
- Page 86 and 87: 17 th International Congress on Nit
- Page 88 and 89: 17 th International Congress on Nit
- Page 90 and 91: 17 th International Congress on Nit
- Page 92 and 93: 17 th International Congress on Nit
- Page 94 and 95: 17 th International Congress on Nit
- Page 96 and 97: 17 th International Congress on Nit
- Page 98 and 99: 17 th International Congress on Nit
17 th <strong>International</strong> Congress on <strong>Nitrogen</strong> <strong>Fixation</strong><br />
Fremantle, Western Australia<br />
27 November – 1 December 2011<br />
Session Details: Tuesday 29 November 2011<br />
Plenary Session 4<br />
1330 - 1500<br />
Authors: Simon Kelly 1,2 , Yasuyuki Kawaharada 2,3 , Artur Muszynski4, Andree Hubber 1,2 , John<br />
Sullivan 1,2 , Niels Sandal 2,3 , Russell Carlson 4 , Jens Stougaard 2,3, and Clive Ronson 1,2.<br />
1 Department of Microbiology and Immunology, University of Otago, Dunedin, New<br />
Zealand<br />
2 Centre for Carbohydrate Recognition and Signalling, University of Aarhus, Aarhus,<br />
Denmark<br />
3 Department of Molecular Biology, University of Aarhus, Aarhus, Denmark<br />
4 Complex Carbohydrate Research Center, University of Georgia, Athens, USA<br />
Presentation Title: The requirement for exopolysaccharide in the Mesorhizobium-Lotus symbiosis<br />
Presentation Time: 1430 – 1500<br />
To investigate the requirement for exopolysaccharide (EPS) in the formation of determinate nodules on Lotus<br />
species, Mesorhizobium loti strain R7A mutants affected in early (exoA, exoB) or mid/late-stages (exoO, exoU,<br />
exoK, mlr5265 and mlr5266) of the EPS biosynthetic pathway were isolated. Elution profiles of EPS extracts<br />
showed that R7A produced both HMW and LMW fractions of EPS whilst mutant strains produced only a LMW<br />
fraction. Early-stage affected mutants formed nitrogen-fixing nodules on L. japonicus cv. Gifu at rates<br />
comparable to wild-type R7A, whereas the mid/late-stage mutants formed uninfected nodule primordia, a few of<br />
which developed into nodules following a lengthy delay. Examination of the symbiotic proficiency of the exoU<br />
mutant on various L. japonicus ecotypes and under differing environmental conditions revealed host and<br />
environment interactions in the requirement for EPS. Analysis of fluorescent protein-tagged strains revealed that<br />
the ineffective mutants were disrupted at the stage of infection thread (IT) development. Symbiotically-defective<br />
EPS and Nod factor mutants functionally complemented each other in co-inoculation experiments. The majority<br />
of full-length ITs observed harboured only the EPS mutant strain and did not show bacterial release, whereas all<br />
nitrogen-fixing nodules contained both mutants. These results suggest that EPS is required at both the stages of<br />
IT initiation and bacterial release and reveal a complex role and requirement for M. loti EPS in determinate<br />
nodule formation. These and other results also suggest that EPS plays a signalling rather than structural role in<br />
the symbiosis. To identify the putative EPS receptor and the downstream signalling pathway, we have carried out<br />
a screen for plant suppressor mutants that form nodules with the exoU mutant. Progress towards the<br />
characterisation of these mutants will be presented.<br />
51<br />
2011
Change language