Importance to understand and improve the nutrient use efficiency in plants with Rice as an example.

1. Nutrient Use Efficiency:
Molecular Mechanism
and Advances
Amandeep Kaur
L-2014-A-12-D

2. Overview

3. Introduction and Importance
Global crop demand will increase by 100 to 110% from 2005 to 2050
http://thewarmongerreport.blogspot.in/2013/08/overpopulation-why-its-happening-and.html
Major challenge: Sustainable Crop Production

4. Sustainable Crop
Production
By expanding
the land area
By increasing
yields per unit
area
Chemical
Fertilizers
http://www.thehindu.com/
http://www.kingbo.com.cn/doce/eye01.asp

5. Nutrient Use Efficiency (NUE)
Ability of a genotype/cultivar to acquire nutrients from growth medium
and/or to incorporate or utilize them in the production of shoot and
root biomass or utilizable plant material (seed, grain, fruits, forage)
Overall performance
Optimum nourishment
Nutrient losses from the field

6. Evaluation of NUE
Hawkesford M J (2012) DOI: 10.1002/9780470015902.a0023734

7. Factors affecting NUE in Plants
Baligar et al (2001) Soil Science and Plant Analysis 32: (7-8): 921-950

8. Improving Nutrient use Efficiency
Agronomy Molecular Breeding
• Nitrate reductase
•Glutamine synthetase
•Alanine amino transferase
Depth
Proliferation
Lateral root production

9. Hawkesford M J and Barraclough P (2011) In:The Molecular and Physiological Basis of Nutrient Use Efficiency in Crops

10. Biotechnology of NUE
Hawkesford M J and Barraclough P (2011) In:The Molecular and Physiological Basis of Nutrient Use Efficiency in Crops

11. Nitrogen Efficiency Engineering
López-Arredondo et al (2013) Int J Dev Biol 57: 595-610

12. Phosphorus Efficiency Engineering
López-Arredondo et al (2013) Int J Dev Biol 57: 595-610

13. Phosphite oxidoreductase System
López-Arredondo et al (2013) Int J Dev Biol 57: 595-610

14. (a) Nanjing6 (NJ6)
(b) Qiangzhonglang2 (QZL2)
(c) RIL-D22
(d) RIL-D04

15. qNGR9: major QTL for N-
mediated growth responses

16. qNGR9 synonymous with DEP1
• NIL-qNGR9 plants: nitrogen
response with respect to plant
height
• NIL-qNGR9 plants over-
expressing dep1-1 cDNA
amplified from QZL2: nitrogen-
insensitive responses
• NIL-dep1-1 plants: largely
unresponsive

17. DEP1: required for N response

18. dep1-32: variant thought to increase
yield of japonica varieties

20. DEP1protein required for vegetative growth
response

21. Different Alleles - Different Response???

22. DEP1 controlling amount and direction of cell
division
Two contrasting effects of dep1-1 allele on plant architecture
•Repressing longitudinal cell division and plant height during
vegetative growth period
•Promoting cell proliferation and panicle branching during the
reproductive stage

23. Differential Effects – to what extent??
• DEP1 regulates both plant developmental responses to nitrogen and
nitrogen metabolism
• dep1-1 allele is involved in nitrogen uptake and assimilation, more
than the DEP1 allele

24. Differential Effects – to what extent??

25. Effect on plant architecture

26. Comparison with the semi-dwarf1 gene
NIL–dep1-1 plants retained their productivity advantage even under
conditions of low nitrogen availability

27. DEP1 protein - a plant-specific G protein γ subunit
Localization of the RGB1-GFP fusion protein in the
root of transgenic cv. Nipponbare plants

28. Up- and Down- regulation of RGB1 confers
phenotype similar to NIL-dep1-32

29. Transgenic plants over-expressing RGB1
show reduced nitrogen response

30. Interaction between RGA1 and DEP1
• d1-1 allele confers lack of RGA1 resulting in severe dwarf phenotype
• Semi-dwarf phenotype of the Chinese cultivar Xueheaizao (XHAZ) is
conferred by the d1XHAZ allele (low abundance of RGA1)

31. Conclusions
• Vast knowledge and genetic modification tools
available
• Complex integrated biological processes
• Better understanding of rhizosphere components
• Improving traits that confer tolerance to nutrient
deficiency

32. ‘Second Green Revolution’
Dream or Reality????