Back in the mid 1900’s, after the tragic days of the Dust Bowl in North America, new agricultural techniques and technologies were developed and distributed in the name of food security. These developments included higher yielding plant varieties, synthetic fertilizers and pesticides, and advancements in irrigation and other management practices. This period in time was termed the Green Revolution, and it truly was a remarkable time. Agricultural advancements that came out of this period have helped us feed the world and stave of starvation for millions of people. Today, issues of hunger and starvation are political problems, not necessarily agricultural ones. However, the human population continues to grow, and today’s 7 billion people is projected to reach up to 10 billion (or more) in the coming decades. The world’s best farmland is either already in use, degraded, or being used for other things. This means that we must find a way to feed a growing population with the diminishing farmland that is available. We may be producing enough food now (despite the distribution problem), but will we be able to produce enough in the future? The hunt for the Green Revolution 2.0 is on.
“According to the [UN's Food and Agriculture Organization], most of the growth in production…has to come from increasing yields from crops. Selective breeding doesn’t seem to be offering the types of dramatic yield increases seen in the past. Meanwhile, genetic engineering has yet to lead to any significant increase in yields. Now, many scientists are saying that we’ve been looking at the wrong set of genes.”
These are the words of Cynthia Graber, author of an article that appeared last month on PBS Online’s NOVANext entitled, “The Next Green Revolution May Rely on Microbes.” In it she explores the argument that increasing future yields will depend on better understanding the soil’s microbial community and its complex interaction with the plant community. The big question: if microbes can be artificially bred – the same way virtually all agricultural plants have been – might they help us increase food production?
Microbial life in the soil is incredibly diverse. In one teaspoon of soil, there can be billions of individual microbes including bacteria, fungi, protozoa, algae, and nematodes. Our current understanding of soil life is extremely limited, akin to our understanding of outer space and the depths of the oceans. That is because, as stated in Graber’s article, “perhaps 1% of all soil microbes can be grown in a petri dish, the conventional model for such research.” This limits our ability to study soil microbes and their interactions with other living things. We do, however, acknowledge that the interactions between the roots of plants and soil microbes is incredibly important.
One major player in these interactions is a group of fungi called mycorrhizae. “Mycorrhizal fungi cannot survive without plants, and most plants cannot thrive without mycorrhizal fungi.” It is a symbiotic relationship, in which the fungi offer plants greater access to water and nutrients, and plants feed sugars derived from photosynthesis to fungi. Recent advancements in genetics have allowed researchers to better analyze the genes in microbes like mychorrizal fungi and determine the functions of them. Through selective breeding, microbes can be produced that will offer even greater benefits to plants, thereby increasing yields. For example, some microbes help plants tolerate heat and drought. Isolating the genes that give microbes these abilities, and then breeding these genes into other microbes might allow for a wider palette of plants to receive this kind of assistance.
In researching this article, Graber followed a Swiss researcher to Colombia where he was testing lines of mychorrhizal fungi on cassava. The fungi were specifically selected to increase a plant’s access to phosphorous. This is one of many experiments that are now under way or in the works looking at specially bred microbes in agricultural production. It’s an exciting new movement, and rather than spoil too much more of Graber’s article, I implore you to read it for yourself. Share any comments you may have in the comment section below, and expect more posts about plant and microbe interactions in the future.
Cynthia Graber appeared at the beginning of a recent episode of Inquiring Minds podcast to talk about her article. I recommend listening to that as well.