Title |
Highly diverse endophytes in roots of Cycas bifida (Cycadaceae), an ancient but endangered gymnosperm |
Author |
Ying Zheng1,2,3, Tzen-Yuh Chiang4, Chao-Li Huang4, and Xun Gong1,2* |
Address |
1Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, P. R. China, 2Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, P. R. China, 3University of Chinese Academy of Sciences, Beijing 100049, P. R. China, 4Department of Life Sciences, National Cheng Kung University, Tainan 701, Taiwan |
Bibliography |
Journal of Microbiology, 56(5),337–345, 2018,
|
DOI |
10.1007/s12275-018-7438-3
|
Key Words |
coralloid root, cyanobacteria, Cycas, diversity, endophyte,
next-generation sequencing technique |
Abstract |
As an ancient seed plant, cycads are one of the few gymnosperms
that develop a root symbiosis with cyanobacteria,
which has allowed cycads to cope with harsh geologic and
climatic conditions during the evolutionary process. However,
the endophytic microbes in cycad roots remain poorly identified.
In this study, using next-generation sequencing techniques,
we investigated the microbial diversity and composition
of both the coralloid and regular roots of Cycas bifida
(Dyer) K.D. Hill. Highly diverse endophytic communities were
observed in both the coralloid and regular roots. Of the associated
bacteria, the top five families were the Nostocaceae,
Sinobacteraceae, Bradyrhizobiaceae, Bacillaceae, and Hyphomicrobiaceae.
The Nectriaceae, Trichocomaceae, and Incertae
sedis were the predominant fungal families in all root samples.
A significant difference in the endophytic bacterial community
was detected between coralloid roots and regular
roots, but no difference was observed between the fungal communities
in the two root types. Cyanobacteria were more dominant
in coralloid roots than in regular roots. The divergence
of cycad root structures and the modified physiological
processes may have contributed to the abundance of cyanobionts
in coralloid roots. Consequently, the colonization of
cyanobacteria inhibits the assemblage of other endophytes.
Our results contribute to an understanding of the species diversity
and composition of the cycad-endophyte microbiome
and provide an abbreviated list of potential ecological roles
of the core microbes present. |