Biological nitrification inhibition in sorghum: the role of sorgoleone production
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T. Tesfamariam, H. Yoshinaga, Santosh Deshpande, Ch. Srinivasa rao, Kanwar Lal Sahrawat, Y. Ando, K. Nakahara, Charles Hash, G. V. Subbarao. (30/6/2014). Biological nitrification inhibition in sorghum: the role of sorgoleone production. Plant & Soil, 379 (1-2), pp. 325-335.
Abstract
Background and aims Nitrification and denitrification
are the two most important processes that contribute to
greenhouse gas emission and inefficient use of nitrogen.
Suppressing soil nitrification through the release of nitrification
inhibitors from roots is a plant function, and
termed “Biological Nitrification Inhibition (BNI)”. We
report here the role and contribution of sorgoleone release
to sorghum-BNI function.
Methods Three sorghum genotypes (Hybridsorgo,
IS41245 and GDLP 34-5-5-3) were evaluated for their
capacity to release sorgoleone, which has BNI-activity,
in hydroponic and soil culture. Sorgoleone released was
measured using HPLC; BNI-activity was determined
using a luminescent recombinant Nitrosomonas
europaea assay.
Results Sorgoleone production and BNI-activity release
by roots are closely associated (1 μg of sorgoleone is equivalent to 1 ATU activity in assay). Purified
sorgoleone inhibited Nitrosomonas activity and suppressed
soil nitrification. Sorghum genotypes release
varying quantity of sorgoleone; GDLP 34-5-5-3 and
Hybridsorgo showed higher capacity for both
sorgoleone release and BNI-activity than did IS41245.
In soil culture, GDLP 34-5-5-3 released higher quantity
of sorgoleone into the rhizosphere, which had higher
BNI-activity, and suppressed soil nitrification to a greater
extent than did by IS41245.
Conclusions These results demonstrate genetic differences
for sorgoleone release and its functional link with
BNI-capacity; there is potential for genetic improvement
of sorghum BNI-capacity and deployment of this
in low-nitrifying sorghum production systems.
