Covering: up to 2018 Plants live in close association with a myriad of microbes that are generally harmless. However, the minority of microbes that are pathogens can severely impact crop quality and yield, thereby endangering food security. By contrast, beneficial microbes provide plants with important services, such as enhanced nutrient uptake and protection against pests and diseases. Like pathogens, beneficial microbes can modulate host immunity to efficiently colonize the nutrient-rich niches within and around the roots and aerial tissues of a plant, a phenomenon mirroring the establishment of commensal microbes in the human gut. Numerous ingenious mechanisms have been described by which pathogenic and beneficial microbes in the plant microbiome communicate with their host, including the delivery of immune-suppressive effector proteins and the production of phytohormones, toxins and other bioactive molecules. Plants signal to their associated microbes via exudation of photosynthetically fixed carbon sources, quorum-sensing mimicry molecules and selective secondary metabolites such as strigolactones and flavonoids. Molecular communication thus forms an integral part of the establishment of both beneficial and pathogenic plant-microbe relations. Here, we review the current knowledge on microbe-derived small molecules that can act as signalling compounds to stimulate plant growth and health by beneficial microbes on the one hand, but also as weapons for plant invasion by pathogens on the other. As an exemplary case, we used comparative genomics to assess the small molecule biosynthetic capabilities of the Pseudomonas genus; a genus rich in both plant pathogenic and beneficial microbes. We highlight the biosynthetic potential of individual microbial genomes and the population at large, providing evidence for the hypothesis that the distinction between detrimental and beneficial microbes is increasingly fading. Knowledge on the biosynthesis and molecular activity of microbial small molecules will aid in the development of successful biological agents boosting crop resiliency in a sustainable manner and could also provide scientific routes to pathogen inhibition or eradication.

Economic growth and human activities challenge the regional harmony of the economy and environment. Based on an evaluation of ecological carrying capacity (ECC), we have constructed a three‐dimensional trade‐off model for socially harmonious development for the Sichuan and Yunnan regions in southwest China. The results demonstrate that there is a continuous increase in socioeconomic coordination (SEC; slope > 0.23) and a change in the ECC in the study area, characterized by subtle fluctuations from 2000 through 2008. This was primarily due to the loss of resource and environment carrying capacity wiping out the profits of SEC. Significant government aid during the postdisaster reconstruction and more attention being paid to the environment in policy resulted in a faster increase in ECC (slope > 0.38) from 2008 to 2016. Based on this trade‐off model, managers could deeply understand the relationship between resources, the economy, and ecology. Summary for Managers Ecological environment protection is increasingly crucial in Sichuan and Yunnan regions as they feel the effects of climate change and human activities. The three‐dimensional trade‐off model measuring socially coordinated development is a modified multiobjective, decision‐making model. Based on this trade‐off model, managers could, understand the relationship between resources, the economy, and ecology. It can help manage our environmental assets and plan ecological conservation, to ensure that the environment maintains its capacity to serve the societal development.

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