IN INOCULANTS Nodulaid - 17th International Nitrogen Fixation ...

Recommendations

Info

17 th International Congress on Nitrogen Fixation Fremantle, Western Australia 27 November – 1 December 2011 Title Trehalose accumulation in osmotically challenged rhizobia and its effect on desiccation tolerance. Authors Andrea Casteriano and Rosalind Deaker Poster Board Number 47 University of Sydney - Faculty of Agriculture, Food and Natural Resources Pre-inoculated seeds are a convenient and much sought after legume inoculant product. However, rhizobia is known to survive poorly on seed mainly due to desiccation stress encountered during the seed coating process. Rhizobia is also known to possess inherent desiccation tolerance mechanisms including the production of compatible solutes such as trehalose through the de novo synthesis. Batch cultures of Bradyrhizobium japonicum (CB1809) and Rhizobium leguminosarum bv. trifolii (TA1) were grown in a defined medium with altered osmotic pressure through the addition of solutes. Increasing the osmotic pressure (1atm to 2.5atm) of the medium resulted in cells with a higher amount of intracellular trehalose. Vacuum drying those cells in the absence of an external protectant showed an improvement in % survival for CB1809 immediately after drying and during storage at RH ≤ 9%. However the accumulation of intracellular trehalose did not result in improved desiccation tolerance for TA1. Cells of CB1809 extracted from peat and dried under vacuum in the absence of an external protectant show a much greater rate of survival not only immediately after drying but also during prolonged storage. Also, cells of TA1 and CB1809 grown in a peat extract have shown a much greater rate of survival after vacuum drying than those cells grown in a liquid medium. In conclusion, osmotically challenging CB1809 and TA1 during growth appears to increase their ability to accumulate intracellular trehalose. However, trehalose accumulation only improved desiccation tolerance of CB1809 and not TA1. Cells were better able to tolerate desiccation after growth in peat and peat extract indicating that not only conditions of nutrient and oxygen limitation play a role but also soluble constituents of peat. 162 2011
17 th International Congress on Nitrogen Fixation Fremantle, Western Australia 27 November – 1 December 2011 Title A MYB coiled-coil type transcription factor interacts with NSP2 and is essential for nodulation in Lotus japonicus Author Zhongming Zhang, Heng Kang, Xiaojie Chu, Chao Wang, Hui Zhu, Songli Yuan, Dunqiang Yu, Zhenzhen Yang Poster Board Number 48 State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University Transcription factor complex formation is a central step in regulating gene expression. In Medicago truncatula, two GRAS family transcription factors, Nodulation Signaling Pathway 1 (NSP1) and NSP2 form a DNA-binding complex to induce specific changes of gene expression, which is essential for the root nodule symbiosis (Hirsch et al., 2009). Using yeast two-hybrid (Y2H) screening, we identified a novel MYB coiled-coil transcription factor, referred as IPN2, which interacts with NSP2 in Lotus japonicus. This interaction was confirmed by protein pulldown assay and BiFC assay in Nicotiana benthamiana. Moreover, IPN2 and NSP2 were co-localized in nuclei of L. japonicus hairy roots. The Y2H assay showed that the GRAS domain of NSP2 was required for interacting with IPN2, while the coiled-coil domain of IPN2 was necessary and sufficient for interacting with NSP2. IPN2 showed strong transcriptional activation activity in yeast cells, and it bound to the NIN promoter in vivo and in vitro. IPN2 was widely expressed in various organs, and showed phloem-specific expression within the vasculature of transgenic hairy roots. Overexpression of IPN2 promoted nodulation, while RNA interference (RNAi) knockdown of IPN2 expression led to decreased nodule formation in L. japonicus. Take together, our results strongly suggest that IPN2 plays an essential role in nodulation. Hirsch, S, Kim, J, Munoz, A, Heckmann, AB, Downie, JA, and Oldroyd, GE (2009). GRAS proteins form a DNA binding complex to induce gene expression during nodulation signaling in Medicago truncatula. Plant Cell 21:545-557. 163 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:
Page 20 and 21:
Page 22 and 23:
Page 24 and 25:
Page 26 and 27:
Page 28 and 29:
Page 30 and 31:
Page 32 and 33:
Page 34 and 35:
Page 36 and 37:
Page 38 and 39:
Page 40 and 41:
Page 42 and 43:
Page 44 and 45:
Page 46 and 47:
Page 48 and 49:
Page 50 and 51:
Page 52 and 53:
Page 54 and 55:
Page 56 and 57:
Page 58 and 59:
Page 60 and 61:
Page 62 and 63:
Page 64 and 65:
Page 66 and 67:
Page 68 and 69:
Page 70 and 71:
Page 72 and 73:
Page 74 and 75:
Page 76 and 77:
Page 78 and 79:
Page 80 and 81:
Page 82 and 83:
Page 84 and 85:
Page 86 and 87:
Page 88 and 89:
Page 90 and 91:
Page 92 and 93:
Page 94 and 95:
Page 96 and 97:
Page 98 and 99:
Page 100 and 101:
Page 102 and 103:
Page 104 and 105:
Page 106 and 107:
Page 108 and 109:
Page 110 and 111:
Page 112 and 113: 17 th International Congress on Nit
show all

IN INOCULANTS Nodulaid - 17th International Nitrogen Fixation ...

Create successful ePaper yourself

Delete template?

Save as template?