Table_3_Interplay between rhizospheric Pseudomonas chlororaphis strains lays the basis for beneficial bacterial consortia.xlsx

Pseudomonas chlororaphis (Pc) representatives are found as part of the rhizosphere-associated microbiome, and different rhizospheric Pc strains frequently perform beneficial activities for the plant. In this study we described the interactions between the rhizospheric Pc strains PCL1601, PCL1606 and PCL1607 with a focus on their effects on root performance. Differences among the three rhizospheric Pc strains selected were first observed in phylogenetic studies and confirmed by genome analysis, which showed variation in the presence of genes related to antifungal compounds or siderophore production, among others. Observation of the interactions among these strains under lab conditions revealed that PCL1606 has a better adaptation to environments rich in nutrients, and forms biofilms. Interaction experiments on plant roots confirmed the role of the different phenotypes in their lifestyle. The PCL1606 strain was the best adapted to the habitat of avocado roots, and PCL1607 was the least, and disappeared from the plant root scenario after a few days of interaction. These results confirm that 2 out 3 rhizospheric Pc strains were fully compatible (PCL1601 and PCL1606), efficiently colonizing avocado roots and showing biocontrol activity against the fungal pathogen Rosellinia necatrix. The third strain (PCL1607) has colonizing abilities when it is alone on the root but displayed difficulties under the competition scenario, and did not cause deleterious effects on the other Pc competitors when they were present. These results suggest that strains PCL1601 and PCL1606 are very well adapted to the avocado root environment and could constitute a basis for constructing a more complex beneficial microbial synthetic community associated with avocado plant roots.

栖稻假单胞菌（Pseudomonas chlororaphis，Pc）类群常作为根际相关微生物组的一部分存在，不同根际Pc菌株通常可对植物发挥有益生理活性。本研究针对三株根际Pc菌株PCL1601、PCL1606与PCL1607的互作关系展开描述，重点关注其对根系生长性能的影响。首先通过系统发育分析发现三株筛选得到的根际Pc菌株存在差异，后续基因组分析验证了该结果，显示其在抗真菌化合物相关基因、铁载体合成相关基因等多个功能基因的携带情况上存在变异。实验室条件下的菌株互作观察显示，PCL1606对富营养环境的适应性更强，且可形成生物膜。植物根系互作实验证实了不同表型在菌株生活史中的作用：PCL1606是最适配牛油果根系生境的菌株，而PCL1607适应性最差，仅在互作数日后便从根系微环境中消失。本研究结果确认，三株根际Pc菌株中有两株（PCL1601与PCL1606）完全兼容，可高效定殖牛油果根系，并对真菌病原菌褐座坚壳（Rosellinia necatrix）展现生防活性。第三株菌株PCL1607单独存在时具备根系定殖能力，但在竞争环境下定殖困难，且当其他Pc菌株存在时，不会对其产生有害影响。上述结果提示，PCL1601与PCL1606可很好地适配牛油果根系生境，可作为构建与牛油果植物根系相关的复杂有益微生物合成群落的基础。