Bacterial Community Structure of Pinus Thunbergii Naturally Infected by the Nematode Bursaphelenchus Xylophilus.

Yang Ma,Bing Liu,Zhao-Lei Qu,Jia-Jin Tan,Fred O Asiegbu,Hui Sun

doi:10.3390/microorganisms8020307

Yang Ma, Bing Liu + Show 4 more

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https://doi.org/10.3390/microorganisms8020307

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Abstract

Pine wilt disease (PWD) caused by the nematode Bursaphelenchus xylophilus is a devastating disease in conifer forests in Eurasia. However, information on the effect of PWD on the host microbial community is limited. In this study, the bacterial community structure and potential function in the needles, roots, and soil of diseased pine were studied under field conditions using Illumina MiSeq coupled with Phylogenetic Investigation of Communities by Reconstruction of Unobserved states (PICRUSt) software. The results showed that the community and functional structure of healthy and diseased trees differed only in the roots and needles, respectively (p < 0.05). The needles, roots, and soil formed unique bacterial community and functional structures. The abundant phyla across all samples were Proteobacteria (41.9% of total sequence), Actinobacteria (29.0%), Acidobacteria (12.2%), Bacteroidetes (4.8%), and Planctomycetes (2.1%). The bacterial community in the healthy roots was dominated by Acidobacteria, Planctomycetes, and Rhizobiales, whereas in the diseased roots, Proteobacteria, Firmicutes, and Burkholderiales were dominant. Functionally, groups involved in the cell process and genetic information processing had a higher abundance in the diseased needles, which contributed to the difference in functional structure. The results indicate that PWD can only affect the host bacteria community structure and function in certain anatomical regions of the host tree.

Highlights

Plants in nature are closely associated with a variety of microorganisms
The results of soil property analysis showed that the soil total nitrogen content, soil pH, and microbial biomass carbon differed between the diseased and healthy soils, and were significantly higher in soils surrounding diseased trees (p < 0.05) (Table 1)
The differences in bacterial community structure and function between healthy and diseased trees were only observed in roots and needles, respectively, suggesting that Pine wilt disease (PWD) can only affect the host bacteria community structure and function in certain anatomic regions of the host tree

Summary

Introduction

Plants in nature are closely associated with a variety of microorganisms. Plant microbial communities play important roles in host fitness. Some plant-related bacteria can have beneficial (symbiotic) effects, promoting plant growth and improving plant stress and disease resistance [2]. Paenibacillus polymyxa can promote the growth of lodgepole pine seedlings via enhancing the nitrogen fixation of the root [3]. ZL2 can increase the resistance of tomato to root rot caused by Fusarium sp. Some bacteria can have neutral, mutualistic, or negative (pathogenicity) interactions with host plants [5,6]. Some actinomycetes can colonize plant root internal tissues and form symbiotic relationships with plants to promote plant growth without causing disease symptoms [7]

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