Corrigendum: Investigating genetic diversity within the most abundant and prevalent non-pathogenic leaf-associated bacteria interacting with Arabidopsis thaliana in natural habitats

[This corrects the article DOI: 10.3389/fmicb.2022.984832.].

Investigating genetic diversity within the most abundant and prevalent non-pathogenic leaf-associated bacteria interacting with Arabidopsis thaliana in natural habitats

Microbiota modulates plant health and appears as a promising lever to develop innovative, sustainable and eco-friendly agro-ecosystems. Key patterns of microbiota assemblages in plants have been revealed by an extensive number of studies based on taxonomic profiling by metabarcoding. However, understanding the functionality of microbiota is still in its infancy and relies on reductionist approaches primarily based on the establishment of representative microbial collections. In Arabidopsis thaliana, most of these microbial collections include one strain per OTU isolated from a limited number of habitats, thereby neglecting the ecological potential of genetic diversity within microbial species. With this study, we aimed at estimating the extent of genetic variation between strains within the most abundant and prevalent leaf-associated non-pathogenic bacterial species in A. thaliana located south-west of France. By combining a culture-based collection approach consisting of the isolation of more than 7,000 bacterial colonies with an informative-driven approach, we isolated 35 pure strains from eight non-pathogenic bacterial species. We detected significant intra-specific genetic variation at the genomic level and for growth rate in synthetic media. In addition, significant host genetic variation was detected in response to most bacterial strains in in vitro conditions, albeit dependent on the developmental stage at which plants were inoculated, with the presence of both negative and positive responses on plant growth. Our study provides new genetic and genomic resources for a better understanding of the plant-microbe ecological interactions at the microbiota level. We also highlight the need of considering genetic variation in both non-pathogenic bacterial species and A. thaliana to decipher the genetic and molecular mechanisms involved in the ecologically relevant dialog between hosts and leaf microbiota.

Development of a Rapid Approach for Detecting Sharp Eyespot Resistance in Seedling-Stage Wheat and Its Application in Chinese Wheat Cultivars

Sharp eyespot, caused by Rhizoctonia cerealis, has become one of the most severe diseases affecting global wheat production in recent decades. Quick and efficient screening methods are required to accelerate the development of cultivars for sharp eyespot resistance in wheat breeding. Here, a two-step colonized wheat kernels (TSCWK) method for the inoculation and classification of sharp eyespot resistance in seedlings was established in a greenhouse. After preliminary verification of the reliability of the method in two replicates, 196 wheat cultivars were assessed for sharp eyespot resistance, and significant correlations were identified among the four replicates (r = 0.78 to 0.84; P < 0.01). Furthermore, the 196 cultivars were scored for sharp eyespot resistance at the milk-ripe stage using traditional toothpick inoculation in the field. Correlation and linear regression analysis showed that the application of this approach at the seedling stage showed good consistency with the traditional field method. Moreover, the scoring of 442 cultivars using the TSCWK method indicated that most cultivars from the Huanghuai valley were susceptible to R. cerealis, suggesting an urgent need to improve sharp eyespot resistance in this region. Additionally, the relative resistance index of sharp eyespot decreased in the surveyed cultivars of the region with time. This study offers a rapid and effective approach for the identification of wheat sharp eyespot resistance and provides valuable germplasm for improving sharp eyespot resistance in wheat breeding.