ACC deaminase : MANAGING

ABIOTIC STRESS IN CROPS

Presented By:ANIL KUMAR

M.Sc. MICROBIOLOGY 1st Year

IARI NEW DELHI

CREDIT SEMINAR- I

MB-691

SEMINAR LEADER: RAJEEV KAUSHIK

CHAIRPERSON : Dr. K . ANNPURNA

stress

Deviation from optimal condition of life

Gene expression

Cellular metabolism

Growth rate

yield

STRESS

ABIOTIC

WATER

DEFICIT

EXCESS

TEMPERATURE

HIGH

LOW

SALT/ION

TOXICITY

DIFFICIENCY

AIR POLLUTION

OTHERS

BIOTIC

4

How abiotic stress affects the growth and development of crop

(Vicers et al., 2009)

PLANT GROWTH AS FUNCTION OF AGE:

Arrows indicate stress onset which

causes growth to slow or stop

But actual yield varies according to the

number and intensity of the stresses

that a plant experiences.

Modified from: XiteBio Technology Inc.

Plant stress control

PLANT RESPONSES TO ABIOTIC

STRESS:

• Closing of stomata

• Change in morphology of plants

• Production of phytohormone

(Auxin, ABA, Ethylene)

SYNTHESIS OF ETHYLENE

1ST

peak/Benefi-cial

peak

2nd

peak/Delete-rious

peak

Ethylene

• A 1-aminocyclopropane-1-carboxylate deaminase is an enzyme that catalyzes the chemical reaction

• This enzyme belongs to the family of hydrolases, those acting on carbon-nitrogen bonds other than peptide bonds

ACC (1-Aminocyclopropane-1-carboxylase) deaminase

CASE STUDY : 1

MATERIALS AND METHODS

• Bacterial strains and growth conditions

• Plant material

• Pot experimental set-up

• Sodium content measurements

• Chlorophyll measurements

• Presence of bacterial endophytes in plant tissue

RESULTS

Table 1: Plants inoculated with P. fluorescens (YsS6) wild-type (YsS6WT), P.

fluorescens YsS6 ACC deaminase deficient mutant (YsS6M), P. migulae 8R6 wild-

type (8R6WT), and P. migulae 8R6 ACC deaminase deficient mutant (8R6M) in the

presence of no salt,165mM salt, or 185mM salt. Each value represents the mean

value. Data was collected on week 11 after seed sowing.

RESULTS

RESULT

Fig. 2. Effect of bacterial endophytes on the growth of tomato plants

in the presence and absence of salt

RESULT

Fig. 3. The effect of the bacterial endophytes on the growth of

tomato plant in the presence of 165 mM salt.

RESULT

Fig. 4. The effect of the bacterial endophytes on the growth of

tomato plant in the presence of 185 mM salt.

CONCLUSION:

• Bacterial endophytes are better adapted to various host plants, they may be more beneficial in facilitating plant growth than their counterpart, rhizospheric-binding bacteria.

• The current study proved that ACC deaminase containing bacterial endophytes increase the resistance of tomato plants to salt and help them to grow under high salt stress conditions.

CASE STUDY : 2

MATERIALS AND METHODS

• Isolation and identification of ACC deaminase-containing rhizobacteria

• Plant material, growth conditions and irrigation treatments

• Preparation of mycorrhizal inoculum

• Inoculation treatments

• Experiment I

• Experiment II

• Plant growth and yield measurement

• AM fungi root colonization

• Biochemical analysis

RESULTS

Fig. 1. Effect of ACC deaminase-containing rhizobacterial inoculations on plant

growth.

RESULTS

Table 1: Effect of microbial inoculations on foliar nutrient uptake of Pisum plants

under different (No salt, 100 mM and 200 mM NaCl) salinity conditions of soil.

RESULTS

RESULTS

Fig. 2. Effect of microbial inoculations on total chlorophyll conditions of soil.

RESULTS

Fig. 3. Effect of microbial inoculations on total MDA (malondialdehyde)

conditions of soil.

RESULTS

Fig. 4. Effect of microbial inoculations on total proline content of Pisum plants under

different conditions of soil.

RESULTS

Fig. 4. Effect of microbial inoculations on ACC concentration enzymatic activities of

Pisum plants under different salinity conditions of soil.

RESULTS

Fig. 6. Effect of microbial inoculations ACS (ACC synthase) enzymatic activities of

Pisum plants under different salinity conditions of soil.

No change in value

RESULTS

Fig. 7. Effect of microbial inoculations on ACO (ACC oxidase) enzymatic activities of

Pisum plants under different salinity conditions of soil.

RESULTS

CONCLUSION:

A combination of SA3 + R + G acted synergistically and

therefore could be a sustainable alternate to mitigate salt stress

induced damage in pea plants which would probably establish a

new developmental equilibrium in order to cope with the initial

stress responses and in establishing plant stress tolerance.

It was established that in presence of ACC deaminase

containing bacteria, higher colonization of AMF and nodulation

of rhizobia could be achieved which is restricted because of high

ethylene concentration under stress.

Future prospects

A range of new innovative technologies needs to be developed and implemented

Needs to implemented on large scale