Assessing the Effect of Litter Species on the Dynamic of Bacterial and Fungal Communities during Leaf Decomposition in Microcosm by Molecular Techniques

Wenjing Xu,Peter Casper,Lingling Shi,Xiaoming Zou,Onchim Chan,Jiao Li,Brian Stevenson

doi:10.1371/journal.pone.0084613

Abstract

Although bacteria and fungi are well-known to be decomposers of leaf litter, few studies have examined their compositions and diversities during the decomposition process in tropical stream water. Xishuangbanna is a tropical region preserving one of the highest floristic diversity areas in China. In this study, leaf litter of four dominant plant species in Xishuangbanna was incubated in stream water for 42 days during which samples were taken regularly. Following DNA extraction, PCR-DGGE (denaturing gradient gel electrophoresis) and clone-sequencing analyses were performed using bacterial and fungal specific primers. Leaf species have slightly influences on bacterial community rather than fungal community. The richness and diversity of bacteria was higher than that of fungi, which increased towards the end of the 42-day-incubation. The bacterial community was initially more specific upon the type of leaves and gradually became similar at the later stage of decomposition with alpha-proteobacteria as major component. Sequences affiliated to methanotrophs were obtained that indicates potentially occurrence of methane oxidation and methanogenesis. For the fungal community, sequences affiliated to Aspergillus were predominant at the beginning and then shifted to Pleosporales. Our results suggest that the microorganisms colonizing leaf bioﬁlm in tropical stream water were mostly generalists that could exploit the resources of leaves of various species equally well.

Highlights

Allochthonous leaf litter inputs are the main carbon and energy sources for headwater streams of forests [1,2]
Along with driving decomposition processes, fungi and bacteria are important intermediaries in energy flow in stream ecosystems, as they can break down large molecules, such as cellulose, chitin, and lignin, into smaller compounds that can be taken up by the biota of higher trophic levels [3,4]
Bacteria can benefit from the compounds released by this process and take advantage of the increased surface area provided by the macerated plant tissue and fungal hyphae for colonization [9]

Summary

Introduction

Allochthonous leaf litter inputs are the main carbon and energy sources for headwater streams of forests [1,2]. Along with driving decomposition processes, fungi and bacteria are important intermediaries in energy flow in stream ecosystems, as they can break down large molecules, such as cellulose, chitin, and lignin, into smaller compounds that can be taken up by the biota of higher trophic levels [3,4]. Fungi are generally more efficient than bacteria in exploiting available resources through invasion and enzymatic hydrolysis of leaf material and lysed hyphae [5,6,7]. Diversity of fungi and their decomposition capabilities during leaf litter decomposition have been investigated from the various studies [8]. Different groups of bacteria and fungi have various biochemical and physiological capabilities, and these differences may influence the leaf decomposition process that underscores the need to examine microbial community structure

Objectives

Methods

Results