TY - GEN
T1 - Prospects for facilitated evolution of effective N₂-fixing associations with cereals
T2 - Nitrogen Fixation with Non-Legumes 1996: 7th International Symposium on Nitrogen Fixation with Non-Legumes
AU - Kennedy, Ivan R
AU - Katupitiya, Sunietha
AU - Yu, Daiguan
AU - Gilchrist, Kate
AU - Deaker, Rosalind
AU - Pereg, Lily
AU - Wood, Craig
PY - 1998
Y1 - 1998
N2 - By analogy with N₂-fixing sugar cane, achieving an effective N₂-fixing association between cereals and diazotrophs may require an endophytic mode of colonization, allowing better protection from oxygen and improved access to carbon substrates. Using nifA-lacZ as a genetic marker on a broad host-range plasmid pVK100, inserted into a range of free-living and associative N₂-fixing organisms, it has been possible to define their mode of colonization of the roots of wheat seedlings in addition to measuring the associated rates of nitrogen fixation. Of these bacterial strains, only 'Herbaspirillum seropedicae', 'Azorhizobium caulinodans' and a mutant strain of 'Azospirillum brasilense' (Sp7-S) displayed significant endophytic colonization of 2,4-D-treated wheat seedlings. By contrast, 'Acetobacter diazotrophicus', 'Azotobacter vinelandii', 'Derxia gummosa' and other 'Azospirillum' strains colonized at the rhizoplane. This chapter discusses these modes of colonization and the probable need for a stepwise process of facilitated evolution of selected diazatrophs and plants before an effective association can be achieved.
AB - By analogy with N₂-fixing sugar cane, achieving an effective N₂-fixing association between cereals and diazotrophs may require an endophytic mode of colonization, allowing better protection from oxygen and improved access to carbon substrates. Using nifA-lacZ as a genetic marker on a broad host-range plasmid pVK100, inserted into a range of free-living and associative N₂-fixing organisms, it has been possible to define their mode of colonization of the roots of wheat seedlings in addition to measuring the associated rates of nitrogen fixation. Of these bacterial strains, only 'Herbaspirillum seropedicae', 'Azorhizobium caulinodans' and a mutant strain of 'Azospirillum brasilense' (Sp7-S) displayed significant endophytic colonization of 2,4-D-treated wheat seedlings. By contrast, 'Acetobacter diazotrophicus', 'Azotobacter vinelandii', 'Derxia gummosa' and other 'Azospirillum' strains colonized at the rhizoplane. This chapter discusses these modes of colonization and the probable need for a stepwise process of facilitated evolution of selected diazatrophs and plants before an effective association can be achieved.
KW - Crop and Pasture Nutrition
KW - Natural Resource Management
KW - Soil Biology
UR - http://trove.nla.gov.au/version/46517966
M3 - Conference contribution
SN - 9780792348733
SN - 0792348737
T3 - Developments in Plant and Soil Sciences
SP - 109
EP - 124
BT - Nitrogen Fixation with Non-Legumes: Proceedings of the 7th International Symposium on Nitrogen Fixation with Non-Legumes
A2 - A Malic, Kauser
A2 - Sajjad Mirza, M
A2 - K Ladha, J
PB - Kluwer Academic Publishers
CY - Dordrecht, Netherlands
Y2 - 16 October 1996 through 21 October 1996
ER -