I want to screen those iron toxic tolerant varieties which can efficiently transfer more iron to rice endospeem if grown in toxic soil condition...
you need to identify existing tolerance limits and their grain ding capacity in large population.
Increased response of rice or wheat in terms of seed yield to iron or zinc doses had been reported. But, most of the accumulated Fe or Zn was partitioned into pericarp and seed coat, instead off the endosperm. The tolerance of rice to high concentration of available iron in soil is mainly attributed to either avoidance mechanism (less iron uptake or lesser translocation of iron from root to shoot) or accumulation of iron into ferritin. Thus, the tolerant varieties are unlikely to translocate more iron into grain. The following articles may be seen for more clues:
file:///F:/RG/Rice_soil/iron_tolerance_mechanism.pdf
http://www.scielo.br/pdf/sa/v66n4/a19v66n4.pdf
http://download.springer.com/static/pdf/958/art%253A10.1186%252F1939-8433-5-27.pdf?originUrl=http%3A%2F%2Fthericejournal.springeropen.com%2Farticle%2F10.1186%2F1939-8433-5-27&token2=exp=1493427851~acl=%2Fstatic%2Fpdf%2F958%2Fart%25253A10.1186%25252F1939-8433-5-27.pdf*~hmac=fcd414b73b1e5fab8ed769bf33a31a49427279bdbdf2423a21a301fdbd2baf00
Enhanced iron concentration in rice grain by the soybean ferritin gene, and barley genes with soybean ferritin gene had been reported
http://www.ugcfrp.ac.in/images/userfiles/28723-Vasconcelos_PlantSc.pdf
http://www.nature.com/nbt/journal/v17/n3/full/nbt0399_282.html
http://journal.frontiersin.org/article/10.3389/fpls.2013.00132/full
However, such transgenic rice with high accumulation of iron as ferritin in grain showed iron deficiency symptoms in leaves under low available iron in soil. In many fields, the iron toxicity (high levels of available iron in soil) usually lasts for a short period. So, once the available iron in soil comes down to desired level, the accumulated iron in leaves and shoot may be utilized by the rice plants. But, if the iron toxicity occurs during the reproductive stage, iron accumulated as ferritin in grain (in transgenic lines) is not partitioned back to the leaves, showing deficiency symptoms. In a very recent article, it is reported to be taken care of (link below):
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5293767/pdf/fpls-08-00130.pdf
It has been reported that the zinc concentration in grain also enhanced. The developed/selected rice variety should have ability to efficiently utilize both low and high iron concentration in soil.
Excellent response Dr Nilay, worth reading. It would be interesting know , how a plant adjusts to toxic level of Fe accompanied with deficient level of Zn in plant leaves , most predominantly on acid Alfisols...
Behera,
Tolerant cultivars does not mean it to uptake more iron from the soil. It will withstand in toxic level of iron and grown well too. I am not sure about its wide transportation from the soil to the endosperm, may be the inability of metal (iron) transporters to transport iron from sufficient to deficient. Toxic condition makes transporter to inefficient. So, this to be approached through the physiological pathway of rice and its metabolism.
Before high iron concentration of iron can be stored in the grain, it should be able to up take by root, transferred to the shoot via xylem loading. Therefore excluder type of rice tolerant variety is not suitable for large capacity of iron storing in grain.
http://ejurnal.litbang.pertanian.go.id/index.php/jpptp/article/view/6144
This is what , we call as Fe-efficient lines.Such lines have inbuilt mechanism to divert comparatively higher proportion of Fe into the edible portion, preferably seeds..
Whether Fe efficient lines are transgenics or else we can get by natural selection?
Can all Fe efficient lines can tolerate high level of Fe and lower Zn in soil?
Fe-effucient lines can be obtained through natural selection since we can have such soil conditions representing both, Fe-deficient and Fe-toxic levels.
This is another very interesting question. It remains to be seen, whether or not, Fe-efficient lines accumulate sufficient Zn or suboptimal Zn without experiencing adverse effect on biomass production...under Fe toxic soil conditions since under such soil conditions , Zn-deficiency is invariably observed...
- Badges
- Science topic
- Similar topics
- Geoscience
- Atmospheric Sciences
- Climate Science
- Climate Change