From Beneficial Bacteria to Microbial Derived Elicitors: Biotecnological Applications to Improve Fruit Quality

Abstract

Food security is the global goal set by the UN in which enough and high-quality food should be available for any person at all times to live a healthy life. Increasing productivity has gone through several milestones in terms of selecting varieties, mineral plant nutrition or transgenic plants. However, additional efforts need to be made to further increase productivity, especially in low-quality soils. Among the new actions to take is to turn the plant into an active player in production, not a passive element that just absorbs nutrients. At that point, the microorganisms that inhabit plant roots become relevant actors since plants select those that best meet their needs in a given environment by releasing different molecules through the root, selecting efficient collaborators. Therefore, isolated strains become active materials to improve plant nutrition and/or trigger plant metabolism to develop biofertilizers and/or biostimulants for agriculture.

The application of active strains to different crops has proved to be effective to increase yield. However, the systemic changes induced in plant metabolism affect many processes, at the metabolic and gene expression level, affecting secondary metabolism pathways. Expression of core and regulatory genes is activated, resulting in modification of secondary metabolites profiles. When these secondary metabolites target human receptors, they are termed bioactives; hence, fruits from plants that have been stimulated contain more bioactives and hold a higher potential benefit for health. Isolation of bacterial determinants (elicitors) from effective strains able to target specific genes of interest in plants is a challenging approach to improve fruit quality, and at the same time, trigger plant defense reducing the need for chemical inputs during production. A case study blackberry illustrates bacterial strain and elicitors effects on fruit quality.