**1. Introduction**

Strawberries are a popular fruit in the US and worldwide. In the US, per capita consumption of strawberries has increased from 2 pounds/person/year to approximately 8 pounds/person/year in recent years [1]. This trend is also apparent in other developed and developing countries of the world. As a result, strawberry growers are using synthetic fertilizers and pest management products to maximize yield. As increased use of synthetic chemicals (fertilizers and pesticides) in crop production and protection has posed a threat to both environment and human health [2], an alternative approach for plant growth promotion, pest management, and sustainable agriculture is being explored all over the world. Strawberry and other fruits and vegetables that are mostly consumed fresh are getting special research attention to innovate production techniques excluding synthetic chemicals [3]. Strawberry growers are specifically eager to find new agro-techniques with special emphasis on the use of both plant growth promotion and nutritional quality improvement in a move toward a more sustainable and environment-friendly approach. In addition,

researchers have been testing novel, sustainable approaches to improve the quality and antioxidant properties of strawberries to increase health benefits. One of the reasons for strawberry demand and consumption has been going up as this fruit is an excellent source of natural antioxidants, such as carotenoids, phenolics, vitamins, anthocyanins, and flavonoids with remarkably high capacity of scavenging free radicals [4]. Improving fruit quality and yield sustainability without synthetic inputs is a research priority for this nutritious fruit. Beneficial microorganisms that are used as bio-fertilizers or bio-stimulants possess the ability to colonize the rhizosphere, plant roots, or both when applied to seeds or plant organs that are used for vegetative propagation (strawberry tips). Some of these microbes have shown potential to promote strawberry plant growth by the release of metabolites into the rhizosphere that may inhibit various pathogens as biocontrol agents [5–8]. However, Tomic et al. [9] found that the response to bacterial inoculation is cultivar-related in strawberries. These microbes were reported to improve plant nutrition and support plant development under natural or stressed conditions as well as increase yield and quality of many important crops and thus may play a crucial role in sustainable crop production in the future [10–12]. A small but significant body of literature also suggests that these microbes can increase strawberry fruit quality in terms of taste and nutritional value and thereby have a positive impact on human health with associated reduction of healthcare costs [13, 14]. The objective of this review is to update our knowledge on the research conducted on improving yield and quality of strawberry by using natural products and beneficial microbes around the globe. Major focus of the review is to relate bio-fortified strawberry fruit with human health benefit. Some novel eco-friendly approaches and potential mechanisms involved with yield and quality improvement in strawberry are also discussed.
