This document discusses the role of microorganisms in crop plants, specifically focusing on biofertilizers. Biofertilizers contain living microorganisms that colonize plant roots and interior tissues to promote growth through nutrient addition or pathogen suppression. They are beneficial as they reduce environmental impacts, prevent groundwater contamination, improve soil quality and yield, and are cost effective. Common microbial inoculants used in biofertilizers include mycorrhizal fungi, plant growth promoting rhizobacteria, and symbiotic nitrogen fixing bacteria. The mechanisms by which microorganisms promote plant growth include biofertilization, phytostimulation through hormone synthesis, rhizoremediation and stress control, and biocontrol through antagonism.

1. Role of Microorganisms in crop
plants

2. Biofertilizers
• Biofertilizers contain living microorganisms when applied to
seed or soil surfaces, colonizes the rhizosphere or interior of
the plant and promote growth by adding nutrients or
suppressing the pathogens.

3. WHY TO CHOOSE BIOFERTILIZERS
• To reduce the impact of chemical fertilizers on environment.
• To stop contamination in ground water.
• To improve the soil quality with the increase in yield.
• It is cost effective.
• Biofertilizers can suppress the pathogens that cause diseases in the plants.

4. Microbial Inoculants
Microbial inoculats include 3 major groups
• Arbuscular mycorrhizal fungi
• Plant growth promoting rhizobacteria.
• Symbiotic nitrogen fixing bacteria.

5. Manufacturing Biofertilizers
Isolation of target microbes
Selection of carrier material
Selection of propagation method
Prototype testing
Large scale testing

6. Mechanisms for plant growth promotion
• Biofertilization :
 Improving the uptake of Nutrients
 Enhancing benefical symbiosis
 Flowering and gain production
• Phytostimulation
 Microbes synthesize hormones.
• Rhizoremediation and stress control
 Degrading soil pollutants
 Produce ACC deaminase
• Biocontrol
 Antagonism
 Systematic response induction

7. Microbes in different crops
MAIZE
Burkholderia Burkholderiasp., Azospirillum sp., Azotobacter sp.,
Herbaspirillum seropedicae,Pseudomonas sp. and Bacillus sp.
RICE
Diazotrophic bacteria, Azospirillum, Bacillus, Paenibacillus,
Brevundimonas, Serratia, Herbaspirillum , and Xanthomonas
enhance rice growth by phytostimulation.
Bacilus and Pseudomonas are used for treatment for fungal diseases.
WHEAT
Bacillus circulans and Cladosporium herbarum and other diverse PGPR
produce anti fungal metabolites, siderophores and secretions of lytic enzymes
that reduce the growth of phytopathogens.

8. THANK YOU !!!