| description |
The phyllosphere, the leaf surface of terrestrial plants, represents the largest biological interface on earth. This habitat is colonized by diverse microorganisms that affect plant health and growth. Not only their identity of these phyllosphere microorganisms, but in particular their responses to rising atmospheric CO2 concentration is poorly understood. Using a massive parallel pyrosequencing technique, we investigated the response of phyllosphere bacterial community in rice to elevated CO2 (eCO2) at tillering, filling, and maturation stages in a rice field under different level of nitrogen fertilization. Our analyses revealed 9 406 distinct OTUs (operational taxonomic units) that could be classified into 8 phyla, 13 classes, 26 orders, 59 families and 120 genera. The family Enterobacteriaceae of Gammaproteobacteria was the most dominant phylotype during rice growing seasons tested, accounting for 60.9-97.2% of the total microbial communities. eCO2 showed the trend of stimulating the relative abundance of dominant phylotype from 60.9-89.4% at aCO2 (ambient CO2) to 66.7-97.2% at eCO2 at all rice growing stages, but suppressing the overall rare phylotypes such as Moraxellaceae, Xanthomonadaceae, Pseudomonadaceae, Bacillaceae, Microbacteriaceae, Sphingobacteriaceae, Flavobacteriaceae, and Comamonadaceae from 6.56-33.6% at aCO2 to 1.31-25.0% at eCO2 in most cases. This contrasting response pattern was largely consistent at all growing stages tested and appeared to be insensitive to nitrogen fertilizations. Furthermore, eCO2 illustrated the trend of enhancing phyllosphere bacterial diversity at rice tillering and filling stages, while the opposite trend was observed at maturing stage. The results of this study provide a novel conceptual framework for moving toward a mechanistic understanding of phyllosphere bacterial responses to global climate changes. |