Legumes of the Sardinia Island: Knowledge on Symbiotic and Endophytic Bacteria and Interactive Software Tool for Plant Species Determination

Abstract

A meta-analysis was carried out on published literature covering the topic of interactive plant microbiology for botanical species of legumes occurring within the boundary of the Italian island Sardinia, lying between the Tyrrhenian and the western Mediterranean seas. Reports were screened for the description of three types of bacterial occurrences; namely, (a) the nitrogen-fixing symbionts dwelling in root nodules; (b) other bacteria co-hosted in nodules but having the ancillary nature of endophytes; (c) other endophytes isolated from different non-nodular portions of the legume plants. For 105 plant species or subspecies, over a total of 290 valid taxonomical descriptions of bacteria belonging to either one or more of these three categories were found, yielding 85 taxa of symbionts, 142 taxa of endophytes in nodules, and 33 in other plant parts. The most frequent cases were within the Medicago, Trifolium, Lotus, Phaseolus, and Vicia genera, the majority of symbionts belonged to the Rhizobium, Mesorhizobium, Bradyrhizobium, and Sinorhizobium taxa. Both nodular and extra-nodular endophytes were highly represented by Gammaproteobacteria (Pseudomonas, Enterobacter, Pantoea) and Firmicutes (Bacillus, Paenibacillus), along with a surprisingly high diversity of the Actinobacteria genus Micromonospora. The most plant-promiscuous bacteria were Sinorhizobium meliloti as symbiont and Bacillus megaterium as endophyte. In addition to the microbial analyses we introduce a practical user-friendly software tool for plant taxonomy determination working in a Microsoft Excel spreadsheet that we have purposely elaborated for the classification of legume species of Sardinia. Its principle is based on subtractive keys that progressively filter off the plants that do not comply with the observed features, eventually leaving only the name of the specimen under examination.

The potential of biostimulants on soil microbial community: a review

“…The important factor in improving the efficiency of the bacteria is to introduce them very close to the root of the developing plants via the in-furrow method or seed treatment (Bender et al, 2022). The relationship between bacteria and crop plants has been investigated for the Leguminosae crop plant family, including alfalfa, beans, clovers, and peas (Muresu et al, 2022). Inoculating these bacteria with soybean also revealed the prevalent function of N-fixing bacteria as biostimulants.…”

Seasonal Shifts in Soil Microbiome Structure Are Associated with the Cultivation of the Local Runner Bean Variety around the Lake Mikri Prespa

“…The symbiotic relationships of leguminous crops with soil nitrogen-fixing bacteria [ 31 ] and other endophytic [ 32 , 33 ] and non-endophytic bacteria [ 34 , 35 , 36 , 37 ] have been extensively studied in the literature, given their contribution to agricultural sustainability and productivity [ 38 , 39 , 40 ] by initiating nutrient cycling in nutrient-depleted soils [ 41 ]. Agronomically important examples of nitrogen-fixing symbiosis in the Fabaceae family, include the common bean ( Phaseolus vulgaris L.) with Rhizobium etli , and lentils ( Lens culinaris Medik.)…”

Ecology and Evolution of Plants in the Mediterranean Basin: Perspectives and Challenges

“…Finally, last but not least, an increasing attention should be paid by future investigations to the contribution given by interactions between vascular plants and other organisms, especially those able to establish bio-chemical interactions as viruses, bacteria, and fungi. This aspect is explored in our Special Issue by Muresu et al [15], who investigated the interactions among some Fabaceae species and symbiotic and endophytic bacteria in Sardinia. This paper shows an intriguing field of plant biodiversity research, with important applications to understand the trajectories of plant evolution as strongly conditioned by interactions among plants and other organisms.…”

“…There is increasing evidence that biological diversity is not a static concept but needs to be continuously monitored at multiple spatial scales, from regional [6], to local [7], to detailed niche adaptation [10]. If we go further to the very detailed, even organisms, such as plants and animals, can be considered at spatial scale as we are aware that they (we) are true ecosystems [15]. The comprehension of biodiversity at multiple spatial scales is, therefore, a crucial challenge for the research on plant ecology and the evolution of Mediterranean plants in future decades.…”