Vila Taissa, Nazir Rashid, Rozental Sonia, Dos Santos Giulia M P, Calixto Renata O R, Barreto-Bergter Eliana, Wick Lukas Y, van Elsas Jan Dirk
Laboratório de Biologia Celular de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brazil.
Department of Microbial Ecology, Groningen Institute for Evolutionary Life Sciences, University of GroningenGroningen, Netherlands; Department of Environmental Sciences, COMSATS Institute of Information TechnologyAbbottabad, Pakistan.
Front Microbiol. 2016 Oct 27;7:1689. doi: 10.3389/fmicb.2016.01689. eCollection 2016.
The soil bacterium strain BS001 can interact with varying soil fungi, using mechanisms that range from the utilization of carbon/energy sources such as glycerol to the ability to reach novel territories in soil via co-migration with growing fungal mycelia. Here, we investigate the intrinsic properties of the BS001 interaction with the basidiomycetous soil fungus sp. strain Karsten. In some experiments, the ascomycetous 302 was also used. The hyphae of sp. strain Karsten were largely hydrophilic on water-containing media versus hydrophobic when aerial, as evidenced by contact angle analyses (CA). Co-migration of strain BS001 cells with the hyphae of the two fungi occurred preferentially along the - presumably hydrophilic - soil-dwelling hyphae, whereas aerial hyphae did not allow efficient migration, due to reduced thickness of their surrounding mucous films. Moreover, the cell numbers over the length of the hyphae in soil showed an uneven distribution, i.e., the CFU numbers increased from minima at the inoculation point to maximal numbers in the middle of the extended hyphae, then decreasing toward the terminal side. Microscopic analyses of the strain BS001 associations with the sp. strain Karsten hyphae in the microcosms confirmed the presence of BS001 cells on the mucous matter that was present at the hyphal surfaces of the fungi used. Cell agglomerates were found to accumulate at defined sites on the hyphal surfaces, which were coined 'fungal-interactive' hot spots. Evidence was further obtained for the contention that receptors for a physical bacterium-fungus interaction occur at the sp. strain Karsten hyphal surface, in which the specific glycosphingolipid ceramide monohexoside (CMH) plays an important role. Thus, bacterial adherence may be mediated by heterogeneously distributed fungal-specific receptors, implying the CMH moieties. This study sheds light on the physical aspects of the BS001 - sp. strain Karsten interaction, highlighting heterogeneity along the hyphae with respect to hydrophobicity and the presence of potential anchoring sites.
土壤细菌菌株BS001可与多种土壤真菌相互作用，其作用机制包括利用甘油等碳/能源，以及通过与生长中的真菌菌丝体共同迁移到达土壤新区域的能力。在此，我们研究了BS001与担子菌土壤真菌sp.菌株Karsten相互作用的内在特性。在一些实验中，还使用了子囊菌302。通过接触角分析（CA）证明，sp.菌株Karsten的菌丝在含水培养基上大多为亲水性，而气生菌丝则为疏水性。菌株BS001细胞与两种真菌的菌丝共同迁移优先沿着 - 可能是亲水性的 - 土壤中生长的菌丝进行，而气生菌丝由于其周围黏液膜厚度减小，不允许有效迁移。此外，土壤中菌丝长度上的细胞数量显示出不均匀分布，即菌落形成单位（CFU）数量从接种点的最小值增加到延伸菌丝中部的最大值，然后向末端减少。对微观世界中菌株BS001与sp.菌株Karsten菌丝的关联进行显微镜分析，证实了BS001细胞存在于所用真菌菌丝表面的黏液物质上。发现细胞聚集体聚集在菌丝表面的特定位置，这些位置被称为“真菌相互作用”热点。进一步获得的证据支持了这样的观点，即物理性细菌 - 真菌相互作用的受体存在于sp.菌株Karsten的菌丝表面，其中特定的糖鞘脂神经酰胺单己糖苷（CMH）起着重要作用。因此，细菌黏附可能由异质分布的真菌特异性受体介导，这意味着CMH部分。本研究揭示了BS001 - sp.菌株Karsten相互作用的物理方面，突出了菌丝在疏水性和潜在锚定位点存在方面的异质性。
