Ascomycete fungal communities associated with early decaying leaves of Spartina spp. from central California estuaries

Abstract

Ascomycetous fungi play an important role in the early stages of decomposition of Spartina alterniflora, but their role in the decomposition of other Spartina species has not been investigated. Here we use fingerprint (terminal restriction fragment length polymorphism) and phylogenetic analyses of the 18S to 28S internal transcribed spacer region to compare the composition of the ascomycete fungal communities on early decay blades of Spartina species (Spartina alterniflora, Spartina densiflora, Spartina foliosa, and a hybrid (S. alterniflora x S. foliosa)) collected from three salt marshes in San Francisco Bay and one in Tomales Bay, California, USA. Phaeosphaeria spartinicola was found on all samples collected and was often dominant. Two other ascomycetes, Phaeosphaeria halima and Mycosphaerella sp. strain 2, were also common. These three species are the same ascomycetes previously identified as the dominant fungal decomposers on S. alterniflora on the east coast. Ascomycetes appeared to exhibit varying degrees of host specificity, demonstrated by grouping patterns on phylogenetic trees. Neither the exotic S. alterniflora nor the hybrid supported fungal flora different from that of the native S. foliosa. However, S. densiflora had a significantly different fungal community than the other species, and hosted at least two unique ascomycetes. Significant differences in the fungal decomposer communities were also detected within species (two clones of S. foliosa), but these were minor and may be due to morphological differences among the plants.

Cordgrass Biomass in Salt Marshes

“…Below-and above-ground biomasses are key functional traits that play very important roles in the ecological behavior of cordgrasses. Thus, Spartina biomass influences on the carbon content of marsh sediments (Tanner et al, 2010), the marsh carbon stock (Wieski et al, 2010), marsh methane emissions (Cheng et al, 2010), salt marsh microbial community (First & Hollibaugh, 2010;Lyons et al, 2010), grazing (Burlakova et al, 2009), sediment dynamic (Neumeier & Ciavola, 2004;Salgueiro & Cacador, 2007;Li & Yang, 2009), etc. Cordgrass biomass affects the emergent of the habitat structure, facilitating succession development by providing a base for habitat development (Castellanos et al, 1994;Figueroa et al, 2003;Proffitt et al, 2005;Castillo et al, 2008b).…”

GÉNEROS DE HONGOS NECROFÍTICOS ASOCIADOS A HOJAS DE Spartina argentinensis Parodi Y Panicum prionitis Ness en Argentina

“…Phaeosphaeria spartinicola y Mycosphaerella sp. serían algunas de las especies más frecuentemente involucradas en el proceso de degradación de hojas del género Spartina (Lyons et al, 2010). Todas las muestras bajo estudio estuvieron asociadas al menos a un género ligninolítico.…”

“…Para este fin, el alto porcentaje de lignina de ambas especies es la principal barrera a vencer (Himmel et al, 2007;Gómez et al, 2008). Existe información sobre descomposición de especies del género Spartina creciendo en costas marinas, donde se señala la relevancia que tienen los hongos en el proceso (Gessner y Goos, 1973;Newell y Porter, 2000;Newell 2001a;Newell 2001b;Buchan et al, 2002;Kohlmeyer y Volkmann-Kohlmeyer, 2002;Blum et al, 2004;Lyons et al, 2005;Lyons et al, 2010) puesto que este grupo de organismos se destaca por su capacidad ligninolítica (Benner et al, 1986;Newell and Porter, 2000).…”

Fungal Biodiversity in Salt Marsh Ecosystems

“…The colonization of fungi on standing dead halophytes commences during the early stages of decomposition before leaf fall to the salt marsh sediment surface [ 20 , 21 ]. The decomposition of the senescent tissues of halophytes by salt marsh fungi is brought about by the direct penetration of the host cell wall and the production of enzymes active in degrading lignocellulosic compounds, such as lignin, cellulose, and hemicellulose [ 22 , 23 , 24 , 25 , 26 ]. Bacterial communities are the major decomposers in the latter stage of decomposition [ 27 , 28 ].…”