This strategic proposal focuses on the microbiota (bacterial and fungal community) that exists on the surface of and inside plants. It proposes various measures for the development of new technologies for agricultural and material production based on new concepts, through comprehensive understanding of the interactions between plants and microbiome and the combination of strengths of the Japanese basic research and technologies in related areas.

In this proposal, the microbial community interacting with plants are described as "microbiome" which encompasses both bacteria (prokaryotes) and fungi (eukaryotes).

The term "microbial flora" usually refers to groups of microbes (bacteria, archaea, protists, fungi, viruses, etc.) existing in a particular environment (soil, sea, ambient air, living space, inside/on the surface of animals and plants, etc.). Unless specified otherwise, this term in this proposal refers only to the microbial flora that exists on the surface of individual plants (above-ground parts and roots) and inside them (plant tissue). The microbial flora that exists in the rhizosphere (around the roots) or soil will be termed "rhizosphere ?-" or "soil ---."

The world population has been rapidly growing, and is anticipated to exceed 8 billion by the year 2030 (by that time, the demand for major agricultural products will be 40-50% greater than the current level). In addition, the burden on the environment due to nitrogen and phosphorus of agricultural origin will become more serious, along with a significantly greater influence of environmental changes (water shortage, global warming, etc.) on agriculture. In these circumstances, it is imperative that we develop a form of agriculture, which can cope with environmental changes without increasing the load on the environment. Furthermore, we need to seriously consider solutions for the current situation in Japan, i.e., rapidly decreasing birth rates, accelerated aging society, and sharp decrease in the farming population, which has caused a crisis in the conventional Japanese agricultural base.

Thus, maintaining and increasing the agricultural production despite severe environmental changes, while saving nitrogen, phosphate fertilizers, and water, is a major challenge for global sustainable advancement. In addition to that, to maintain Japanese agricultural base, it is important to develop new methods of agricultural production, which are less-labor and more-cost effective while yielding higher added value products. There are great expectations for science and technology to help achieve these goals. The development of innovative cultivation-related technologies (biological pesticide, biological fertilizers, crop protection, etc.) is one of the major challenges.

The microbe/microbiota has traditionally been anticipated to have association with growth and diseases of plants and animals. Research in this field has been challenged high complexity of microbe. However, thanks to remarkable improvements in recent years in the performance of next-generation sequencers, a major movement towards the complete elucidation and control of microbiota is now beginning. Research on microbiota in humans has made significant advancements and the results have been applied in new health/medical care technology. Research on microbiota in plants is also activating recently, although it is still at the level of basic research. Plants support our daily lives, as well as all life on Earth, through photosynthesis-based primary production. Because agricultural crops, resource crops, and trees are mainly cultivated in the open air field, there are interactions with great amount of microbiota from germination to the harvesting stage. To date, basic and applied research, as well as application at the field/society level, has focused on fungi such as rhizobia and mycorrhizal fungi (which are representative microbes that provide benefits to their plant hosts through mutualistic interactions). However, there has been almost no research on interactions with the other huge amount of microbiota (revealed by next-generation sequencers). Today, great competition is beginning in this field of research across the world.

Japan has a competitive edge in terms of research in fields such as plant science, microbiology, and natural organic chemistry over other countries, which will serve as the major role for promoting research in the above-mentioned fields. If research and development including those are strategically promoted, it might be possible for us to produce world-leading outcomes. This strategic proposal pertains to the 4 tasks listed below. These R&D tasks will enable us to obtain a comprehensive understanding of plant-microbiota interactions and to establish basic control technology.

　　Task 1: Understanding, isolation, and culture of microbial flora
　　Task 2: Identification and functional analysis of factors involved in plant-microbial flora interactions
　　Task 3: Evaluation/Assessment and re-designing based on-field measurements
　　Task 4: Application for agricultural material development, crop production/protection, and effective utilization

"Tasks 1 and 2" pertain to obtaining a comprehensive understanding of the microbiota, which interacts with plants, but has not been sufficiently understood, and of the essential nature of this interaction. In "Task 1," the microbes with beneficial functions for crop production will be selected rapidly and efficiently, and these microbes will be isolated and cultured. In "Task 2," the groups of microbes (cocktail) with useful functions for crop production and chemical signaling molecules for plant-microbe interaction will be identified using the superior Japanese basic research techniques. The knowledge will be the basis for application at the field/society level. In "Task 3," the multi-omics data collected from the cultivation of agricultural crops will be assessed in an integrated manner and the basic technology for re-designing optimum production process for a given situation will be developed. This will enable appropriate control of plant-microbiota interactions during practical agricultural production. "Tasks 1 through 3" are not unidirectional R&D activity (basic to applied), but should be promoted in a circular manner through repeated feedback each other. In "Task 4," frontier R&D activity completely covering "Tasks 1 through 3" will be supported and expanded, to develop new intervention techniques (development of new agricultural materials, creation of cultivation management technology, etc.) and to accelerate the application at the field/society level. The technological goals of these R&D activities include achieving high yield, high stress resistance, disease/pest resistance, high quality, high added value, low environmental load, cost saving, and labor saving. If such a fundamental technological base can be established through promotion of this proposal, it will contribute greatly to the maintenance of sustainable agricultural infrastructure in Japan (enabling high yield with high quality and high added value). In addition, it will enable to maintain or improve of global agricultural crop production capacities and the control of environmental load simultaneously, thus contributing to sustainable production of food and bio-based materials.