Unlocking the Changes of Phyllosphere Fungal Communities of Fishscale Bamboo (Phyllostachys heteroclada) under Rhombic-Spot Disease Stressed Conditions

Lijuan Liu,Feichuan Tan,Renhua Chen,Xiulan Xu,Chunlin Yang,Yinggao Liu,Yufeng Liu,Tiantian Lin,Ming Liu,Xue Wang

doi:10.3390/f13020185

Abstract

As an important nonwood bioresource, fishscale bamboo (Phyllostachys heteroclada Oliver) is widely distributed in the subtropical region of China. Rhombic-spot disease, caused by Neostagonosporella sichuanensis, is one of the most serious diseases that threatens fishscale bamboo health. However, there is limited knowledge about how rhombic-spot disease influences the diversity and structures of phyllosphere fungal communities. In this study, we investigated the phyllosphere fungal communities from stems, branches, and leaves of fishscale bamboo during a rhombic-spot disease outbreak using 18S rRNA sequencing. We found that only the phyllosphere fungal community from stems was significantly affected by pathogen invasion in terms of community richness, diversity, and structure. FUNGuild analysis revealed that the major classifications of phyllosphere fungi based on trophic modes in stems, branches, and leaves changed from symbiotroph-pathotroph, no obvious dominant trophic mode, and symbiotroph to saprotroph, saprotroph–pathotroph–symbiotroph, and saprotroph–symbiotroph, respectively, after pathogen invasion. The fungal community composition of the three tissues displayed significant differences at the genus level between healthy and diseased plants. The associations among fungal species in diseased samples showed more complex co-occurrence network structures than those of healthy samples. Taken together, our results highlight the importance of plant pathological conditions for the assembly of phyllosphere fungal communities in different tissues.

Highlights

The phyllosphere is composed of aerial parts of plants, such as leaves, stems, flowers, buds, and fruits [1,2]
Less is known about fungi, there have been studies analyzing the fungal community in the phyllosphere of different plant species (e.g., Arabidopsis, wheat, rice, maize, Populus, and tropical mangrove) [4,8–12]
We found that Ascomycota was the most prevalent phylum associated with all tissue samples, including healthy stems, branches, and leaves, which might indicate that phyllosphere fungal phylotypes of different plant tissues are consistent at the phylum level

Summary

Introduction

The phyllosphere is composed of aerial parts of plants, such as leaves, stems, flowers, buds, and fruits [1,2]. Phyllosphere microorganisms (mainly bacteria, filamentous fungi, yeast, algae, etc.) are some of the most important components of microbial communities on Earth [3]. These microorganisms contain both epiphytic microorganisms inhabiting plant tissue surfaces and endophytic microorganisms living asymptomatically within plant tissues [3]. A number of studies using either traditional culturedependent methods or high-throughput sequencing technologies have shown that the phyllosphere bacterial community basically consists of the bacterial phyla Proteobacteria, Actinobacteria, and Bacteroidetes across different plant species [5–7]. Less is known about fungi, there have been studies analyzing the fungal community in the phyllosphere of different plant species (e.g., Arabidopsis, wheat, rice, maize, Populus, and tropical mangrove) [4,8–12]

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