Combining the Seed Endophytic Bacteria and the Back to the Future Approaches for Plant Holonbiont Breeding

Abstract

Given the limits of intensive agriculture (pollution, degradation of biodiversity, or soil desertification), it is necessary to develop sustainable alternatives to respond to future agricultural demand. Among these sustainable alternatives is the use of microbial biostimulants. Despite convincing scientific studies on them, their agricultural use remains minor. This can be explained by the lack of efficiency and reliability of their use. This review proposes to develop efficient microbial biostimulants based on the combination of two approaches, namely that of endophytic bacteria from seeds and the Back to the Future approach. Seed endophytic bacteria have a major agroindustrial potential insofar as they stand out from other microbial agents by their resistance, competitiveness, efficiency, and vertical transmission. Contrary to modern cultivars, non-domesticated plants harbor microbiomes which have not been impacted by the processes of domestication and agriculture intensification. The Back to the Future suggests therefore to use interesting microorganisms isolated from non-domesticated plants and to integrate them into modern cultivars. This could result in the rehabilitation of modern microbiomes and lead to make crop cultures more resistant and resilient. The idea consisting in the combination of both approaches aims at obtaining optimized microbiomes. Particular emphasis is placed on integrating these innovative microbiomes into variety breeding programs. Indeed, given the importance of plant-microorganism interactions, particularly from an agronomic point of view, taking the hologenome into account as a unit of selection in breeding programs is essential. This integrative and unprecedented approach to designing breeding programs is promising with a view to reconciling productivity and preservation of agroecosystems.

Seed Endophytic Bacteria of Pearl Millet (Pennisetum glaucum L.) Promote Seedling Development and Defend Against a Fungal Phytopathogen

“…Siderophores are iron-chelating agents that have a greater affinity for ferric ions and convert insoluble ferric form of iron to soluble ferrous form which are easily accessible to the plant. Siderophore producing bacteria also reduce the growth of pathogenic fungi by reducing the iron availability in soil ( Afzal et al, 2019 ; Duponnois and L’Hoir, 2021 ; Kumar et al, 2021 ). In both trials, we found that isolates KAS1, and KAS4 significantly increased the root-shoot lengths, biomass, and photosynthetic pigments in seedlings, and both isolates were the highest producers of IAA and the best P solubilizers ( Table 2 ).…”

Wheat endophytes and their potential role in managing abiotic stress under changing climate

“…The knowledge generated on the signalling pathways and the metabolites with their role in abiotic stress management in wheat can help in devising the strategies for overexpression of specific gene cluster or repression of the undesired genes so that the losses due to abiotic stresses can be minimized. A consolidated approach is also in foresee for using endophytic micro-organisms' profile or their metabolomics as one of the selection criteria in breeding climate resilient varieties (L'Hoir & Duponnois, 2021). However, the diversity of endophytic micro-organisms and the potential of metabolic signals suggest a multidimensional network of competing and symbiotic interactions in the endosphere of plants, making it difficult to simulate in in vitro experiments.…”

Host genotype, soil composition, and geo-climatic factors shape the fonio seed microbiome

“…In addition, the microbiome plays a crucial role in plant growth and development, nutrient uptake, and protection against biotic stress. Arguably, plants are holobionts meaning that a community of microbes coevolves with their host contributing to host phenology and fitness [ 38 ]. Therefore, microbes perform crucial functions throughout plant life history [ 49 ].…”