Root genetic research and its applications in plant breeding

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Seminar-II

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By-Om Prakash PatidarSr. M.Sc. Genetics and plant breedingUniversity of agricultural sciences, Dharwad

Introduction

Roots and its types

conclusion

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Progress of molecular root genetic research

Importance of genetic improvement of roots

Root phenotyping methods

What is a root?

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Modification of roots

Tape root modifications

Radish Turnip Legumes Rhizophora

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Adventitious root modifications

Sweet potatoCuscuta

Banyan tree Wheat fibrous root

Dicot root

monocot root

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Mechanisms for coping with submergence and waterlogging in rice

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Radial oxygen loss

Why crop root improvement breeding?

1. Increasing productivity

• To feed growing population- 9 billion by 2050.

• High yield is possible through large and filled sink size (i.e. filled grains). This can be done when root supplies sufficient nutrients to above ground plant parts especially to grains along with photosynthates.

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2. Enhancing tolerance to abiotic stresses

• Drought resistance-a boon for rainfedagriculture. “More crop per drop”.

• salinity resistance-20% of the world’s cultivated land and near half of all irrigated lands are affected by salinity.

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3. Improving efficiency of nutrients supplied• Excess nutrients remain unused and washed off from fields to

rivers, poisoning coastal water.

• N2 pollution-Third major threat after biodiversity loss and climate change.

• Nutrient deficiencies-

for eg. Only 10-20 % of supplied P is available to plants.

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Progress of molecular genetic research on crop roots

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Gene networks controlling root development in modelcereal rice

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Traits observed and their roles in water uptake under drought

morphological

Functional

Anatomical

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Architectural

Anatomical

Biological and biochemical

Root traits increasing P uptake Benefits Costs

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Case study-Marker assisted selection to introgress rice QTLs

controlling root traits into an Indian upland rice variety

- Steele et al., 2006

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No.

MABC and pyramid crossing scheme to introgress root trait QTLs

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Relative grain and straw yield (t /ha) performance of NILs in irrigated and

non-irrigated regimes, 2004 at GVT Research Farm, Ranchi.

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Case studyControl of root system architecture by DEEPER ROOTING 1

increases rice yield under drought conditions

Uga et al., 2013

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Location of DRO1 gene in NILs and root distribution of IR64 and Dro1-NIL.

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Effect of DRO1 on root growth angle and root gravitropic curvature

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Expression analysis of DRO1

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Case studyA Soybean b-expansin gene GmEXPB2 intrinsically involved in

root system architecture responses to Phosphorous deficiencies

Guo et al., 2011

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Sub cellular localisation of GmEXPB2 fused to GFP in epidermal onion cells

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Expression pattern analysis for GmEXPB2 under low and high P availability

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Histochemical detection of GUS activity under the control of the GmEXPB2 promoter

in transgenic soybean hairy roots at two P levels.

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Effects of over-expression and knockdown of GmEXPB2 on root growth and Pefficiency of transgenic soybean plants.

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Long-term effects of Pi starvation on growth of Arabidopsis GmEXPB2 over-expressing lines

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Case studyA gene in the multidrug and toxic compound extrusion

(MATE) family confers Aluminium tolerance in sorghum

Magalhaes et al., 2007

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Expression and localization of SbMATE

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S- sensitiveT- tolerant

Membrane localization of the SbMATE protein in epidermal onion cells.

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Expression of SbMATE in transgenic A. thaliana plants

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Case study

Mutational reconstructed ferric chelate reductase confers

enhanced tolerance in rice to iron deficiency in calcareous soil

Ishimaru, et al., 2007

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Uptake and transport of Fe as monitored by using PETIS

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Growth features of transgenic rice plants containing the refre1/372 gene and vector controls grown in calcareous soil (pH 8.5) and in bonsol (normal soil)

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Plant height (70 DAT) chlorophyll content (70 DAT)Dry weight of

shoots (without grain)

Grain yield

Growth features of transgenic rice plants containing the refre1/372 gene and vector controls grown in calcareous soil (pH 8.5) and in bonsol (normal cultivated soil)

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Methods for root phenotyping

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Imaging techniques for roots

Gel observation chambers (Barley roots)Magnetic resonance imaging (CT-MRI) of maizeroots and soil water.

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Rhizobox

2D non-invasive imaging

The 3D transparent growth system scanning strategy of the 3D laser scanner

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Procedure to vectorize an entire root system

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Example of vectorised maize root system

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conclusion

Thank you

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The roots of all goodness lie in the soil of appreciation for goodness