Diversity and distribution pattern of bacterial community on bark surface of Larix principis-rupprechtii

Abstract:

Epiphytic microorganisms on the bark surface play an important role in host plants' health and adaptability. The maintenance mechanism of microbial community structure and diversity in bark microhabitats need attention. [Objective] We studied the distribution characteristics and fitness mechanisms of the bacterial community on the bark surface of Larix principis-rupprechtii along elevation gradients and light in Pangquangou Natural Reserve.[Methods] By using PCR-DGGE and high-throughput sequencing technology, we studied the structure of bacterial community. By using nonmetric multidimensional scaling (NMDS) ordination, we analyzed the spatial distribution characteristic of bacterial community. By using redundancy analysis, we analyzed the relationship between bacterial community and environmental factors and by using One-way ANOVA, we compared bacterial community composition between sunny and shady surface. Based on zero-deviation analysis, the driving factors of bacterial community assembly on the shady and sunny surface were studied. [Results] Bacterial community structure was significantly different among elevation gradients (ANOSIM; P<0.05). The redundancy analysis showed that pH and total carbon (TC) on bark surface were significantly correlated with the community structure (P<0.05). The relative abundances of photosynthetic autotrophic bacteria (norank_Cyanobacteria) on the sunny surface were significantly higher than those on shady one, while the relative abundance of Rhizobiales showed an opposite trend. We suggested that light might be a driving factor in determining the structure of bark bacterial community. The results of zero-deviation analysis showed that the diversity pattern of the bacterial community on the bark surface was mainly affected by environmental filtration. [Conclusion] The determination processes were dominant factors in shaping the structure and diversity pattern of bacterial community on the bark surface of Larix principis-rupprechtii in this area.

Key words:community assembly;the bark surface;bacteria community;deterministic process