Description of Initiative

This Grand Challenge proposal focuses on an essential but relatively untapped resource, plant roots and their root microbiomes, to improve agronomic yield and quality while simultaneously reducing dependence on water, fertilizer and pesticide inputs. Target outputs include improvements in plant growth, yield and resistance to stresses as a result of improved understanding of root function and the roles of the root microbiome in plant health. The success of this proposal is dependent on the integration of expertise across COALS, Texas A&M AgriLife Research and Extension Service. Being a part of a land-grant institution, these entities have the mission of improving the lives of Texans and the world by increasing the amount of safe high quality food and fiber needed to support our growing world. Integration of college and agency resources is key to facilitating the rapid validation and translation of results from laboratory and greenhouse studies to field applications to meet the needs of the diverse soil and climatic conditions found across Texas.

Current levels of food production are largely a result of breeding research and technology transfer initiatives, as part of the Green Revolution that increased agricultural production worldwide, particularly in the developing world. Dr. Norman Borlaug is credited with being the  “Father of the Green Revolution” and with saving more lives than anyone else in history. The success of the Green Revolution was due largely to the selection of improved crops that used more energy for seed production than growth, and relied on the unrestricted use of water and fertilizers. We now face challenges not envisioned during the Green Revolution. Most especially, water and arable land are becoming increasingly scarce: subject to high levels of competition, and costs (monetary and environmental) for fertilizers is increasing.  Additionally, many chemicals used to control soil borne plant pathogens are being removed from the market, leaving large vulnerabilities in our ability to control diseases. Crop productivity is historically addressed through breeding programs that focus on above-ground parameters, with impressive results in the past. However, during the past decades the rate of yield increase/year has decreased dramatically. Changing global economics is complicating the need for increasing primary food production. As countries become more affluent, demand for land for animal production is increasing, as is demand for fiber and energy production.  It is predicted that by 2050 the world may need to support 9 billion people, meaning we must increase food production by 70-100%. By 2050, climatic conditions will change, global temperatures will rise 2-5 ^oC, rainfall will become less predictable, and atmospheric CO₂ and methane will increase the occurrence of severe weather. These climatic changes will impact all aspects of plant growth, development, reproduction and the plant’s ability to respond to both abiotic and biotic stresses. The world needs the next Green Revolution to “Feed Our World” while simultaneously “Protecting Our Environment” and “Improving Our Health.”

Plant Health: A New Strategic Plan

Plant yield varies tremendously depending on location and climate. The actual yield of a crop is usually below its theoretical yield, and the difference is known as the “yield gap.” If we can reduce or eliminate this yield gap, then agricultural production could increase 45-70%.  Currently, many yield gaps are attributed to deficits in water, nutrients, or pesticides. However, as these key parameters become increasingly limited, alternate approaches need to be embraced. In the arena of human health, recently the Human Microbiome Project confirmed that microbial cells outnumber human cells 10 to 1 (1,000 trillion to 100 trillion) and that these microbes play essential roles in almost every aspect of human health, from protecting our skin to digesting food and protecting us from pathogens. A new focus in agricultural production is to understand how plant-associated microorganisms affect plant development, growth and health. It is understood that various parts of a plant hosts distinct communities of microorganisms. These microbes represent additional functioning ‘organelles’ of plants. As the total genetic diversity of these microbes is 3-6 orders of magnitude greater than that of the host, they represent the plant’s second genome that contributes significantly to plant success through fundamental processes including nutrient uptake, regulation of plant growth and development, and in reducing the negative impacts of abiotic and biotic stresses on plant growth and subsequent yield. The plant-microbiome is a key driver for plant health, productivity, and ecosystem functioning.

This proposal will focus our efforts to the plant organ that is arguably the most important for growth, development and yield–the root/rhizosphere system. The root plays critical roles for the plant, including: anchorage, site of all water, mineral and nutrient uptake, site of nutrient storage, location of biogeochemical and microbial processes, and the source of atmospheric carbon sequestration back into soil. In comparison to non-plant associated soil, the microbial community associated with the rhizosphere has lower diversity but significantly higher population numbers. Plant roots secrete 10-40% of their total photosynthetic fixed Carbon through roots, determining which members of the soil microbial community are recruited to the rhizosphere, the microbial community influenced by the root. It is hypothesized that the microbial community may be controlled by a limited number of plant alleles. Therefore, understanding root biology and the root microbiome will lead to intelligent choices in plant breeding for improved root function. This approach is clearly in line with the goal of the National Research Council, to achieve farming systems that are productive, profitable, energy conserving, environmentally sound, conserving of natural resources, and that ensure food safety and quality. COALS, in coordination with Texas A&M AgriLife Research and Texas A&M AgriLife Extension Service, has solid faculty expertise and the state includes regions that mimic many worldwide soil and climatic conditions, which positions us ahead of other institutions. Several departments, including SCSC, PLPM, ENTO, and HORT, plus the IPGB and the TGBS provide a core of faculty and technology expertise. This expertise, coupled with faculty expertise at the thirteen AgriLife centers across the state, can enable us to develop and validate results rapidly and at multiple sites under diverse soil and climatic conditions.