Soil bacteria have the potential to contribute to a greener revolution
- Plants appear to be rather straightforward in their structure. Leaves, flowers, fruits, stems, and roots appear to be the only components of tiny shrubs and towering trees. They are not, however, simple. Being confined to one location necessitated the development of unique personality features.
- Their ability to produce food from sunlight and carbon dioxide in the air has placed them at the center of life on Earth. They are unable to flee, yet they are capable of defending themselves. A remarkable component of their talents is hidden beneath the surface, in the soil from which they sprout and take water, micronutrients, and a variety of other benefits.
The long-drawn historical bond
- Plants and fungus have a long history together. The first evidence of roots may be found in plant fossils dating back to 400 million years, and these roots are fungal associations called rhizoids, implying that roots co-evolved with fungi.
- Penicillium species, the fungus from which Alexander Fleming derived the antibiotic penicillin, are a good example. Mycorrhizae, or fungus–root connections, appear to be simple mutualisms that benefit both parties at first appearance.
- The root-invading fungus feeds on the plant’s nutrients, while the plants benefit from the microbe’s supply of hard-to-find elements like phosphorus. However, there is a deeper connection.
Experiments were conducted with birch and fir saplings housed in clear plastic bags containing radioactive carbon dioxide gas:
- By photosynthesis, the birch turned this tagged gas into radioactive sugars, and after two hours, traces of this radioactive sugar emerged in the leaves of surrounding fir seedlings. The exchange occurs mostly through the mycelia of fungi, but it may also occur across the forest, with young trees labouring in a dry region receiving assistance from their lucky counterparts.
- Rhizobacteria are bacteria that connect with roots and are plant growth promoters in a wide range of species. Mutualism operates in these connections as well, just as it does in fungi. These bacteria provide a wide range of benefits to plants in exchange for carbohydrates. They may aid plants in warding off infections that cause root illnesses. They may even cause a disease to develop systemic resistance throughout the plant.
The green revolution time
- Our country’s agricultural production has changed dramatically as a result of the green revolution. The establishment of hybrid crop plant varieties was crucial to this.
- Today, the vast majority of commercially farmed crops are hybrids, which are created by crossing two inbred lines, with the first-generation hybrid offspring displaying vigour not found in either of their parents.
- Heterosis, a feature of hybrid vigour, has been recognised for millennia but is only partially understood.
The fundamental cause
- The rhizomicrobiome – the diverse collection of bacteria that surround every plant’s roots – has revealed a new and exciting feature of hybrid vigour.
- The high biomass of roots in hybrid maize, as well as other beneficial features, are dependent on the right soil bacteria.
- Both inbred parents and hybrid offspring grow equally well in laboratory-sterilized soils that are completely devoid of microorganisms, with no trace of vigour in the latter. Then, one microbe at a time, they began to ‘rebuild’ the soil habitat.
- They were able to achieve the normal parent-offspring vigour difference by introducing only seven bacteria species into the sterile soil.
Source: The Hindu
Syllabus: GS 3 (Agriculture)