For plants immunity is the norm while diseases are mere exceptions.

It is estimated that global agricultural crop loss due to the incidences of pests and pathogens alone is approximately 15% and this is despite use of new generation pest controlling agents. Trillions of dollars are spent annually to invent new poisons to kill pests but does the plant actually need that?

As per plants are concerned, immunity is the norm while diseases are mere exceptions. Had this not been true, we would have never seen greens as there are too many biotic pests for a plant to survive. I am a bit passionate about relating humans or to say all animals to plant genetically as all of us have evolved from a single cell and it means all of life forms have something in common. Immunity, the very basic trait to survive is surely one of the most common traits that life in different forms does share.

COVID-19 has already caused deaths of many millions of human life across the globe and it is understood that the pathogen is not going to go off. Humans will eventually develop immunity against this strand of novel Coronavirus to survive. Corona virus does not kill animals frequently and this is due to the fact that animals have developed immunity against the virus.

The plant immune system is unbelievably very effective. A first layer of defense is formed by an arsenal of immune receptors encoded by hundreds of genes in plant genomes. They function as a switch that determines when the plant immune system is activated. When a receptor gene in the plant matches molecules coded by a gene in the pathogen, the plant immune system is activated and blocks the infection. This switch is a fundamental molecular event that underpins the plant immune circuitry. The resulting immune response is complex and multifaceted but one hallmark is a localized programmed cell death reaction known as the hypersensitive response. Nearly all plant cells have the cellular “suicide” machinery to restrict the spread of pathogen from the infection site to the neighbouring cells. This way plant cells can resist all types of pathogens and parasites, including viruses, bacteria, fungi, oomycetes, and nematodes.

Plant immune receptors are classed into cell surface receptors known as pattern recognition receptors (PRRs) and intracellular receptors of the nucleotide-binding domain and leucine-rich repeat–containing (NLR) family. These two types of immune receptors are not restricted to plants but also occur in animals and a variety of other organisms. PRRs and NLRs detect pathogens and activate immunity through distinct but at times overlapping mechanisms.

We already know how plants (like animals including humans) react and respond against insect pests. Rush of Salicylic acid and production of Methyl Jasmonate and Methyl Salicylate are very common in plants and animals. May I please say that plants are our distant relatives? I leave behind the thoughts to you…