The endophytic fungal community in leaves of a coastal redwood population diversity and spatial patterns

Abstract

SUMMARYLeaf endophytic fungi were isolated from 1 to 12-yr-old leaves of mature trees and basal sprouts of coastal redwood [Sequoia sempervirens (D. Don ex Lamb.) EndL] in a redwood forest in Central California. Almost all samples yielded at least one species. The two most frequent species were Pleuroplaconema sp. and Cryptosporiopsis abietina Petrak. Among isolated taxa are endophytic generalists, species previously known as pathogens and a possible specialist. Species composition in leaves of progressing age in single branches revealed a patchy pattern of leaf colonization without an obvious sequence of succession. Changes in diversity and equitability in the endophytic community with leaf age are linked with differential distribution of some species in young versus old leaves and the increase in species richness in 4-and 5-yr-old leaves. The endophytic communities from leaves of trees and sprouts were generally similar, but with important differences in species richness and in distribution of Pleuroplaconema sp. and Pestalotiopsis funerea (Desm.) Stey. Principal component analysis based on endophytic frequency also indicated closeness of trees and sprouts as groups, but clearly separated each tree from its sprout. Differential susceptibility between trees and sprouts to endophytic infection is suggested on the basis of their endophytic communities.

Endophytic fungi associated with the temperate palm, Trachycarpus fortunei, within and outside its natural geographic range

“…This hypothesis has been supported by isozyme studies (Rodrigues et al, 1993) and other studies investigating the genetic diversity of endophyte isolates (Ha$ mmerli et al, 1992 ;McCutcheon et al, 1993). Changes in infection rates are probably due to physical alterations of the plant tissue or degradation of the leaf cuticle which may make plant hosts more susceptible to invasion with age (Stone, 1987 ;Espinosa-Garcia & Langenheim, 1990).…”

“…The endophytic mycota of plant hosts occurring outside their natural range, in disjunct distributions, have been reported to show both quantitative and qualitative differences when compared with the mycota of the host within its natural range Espinosa-Garcia & Langenheim, 1990 ;Fisher et al, 1993Fisher et al, , 1994. In general, these studies indicate that endophyte assemblages on plant hosts occurring outside the natural range are depauperate and contain different species than those in native habitats.…”

“…The quantitative differences were related to the higher diversity of plant species at one site contributing to an increased source of inoculum. Several other studies on the distribution of endophytes within the host's natural geographic range (Espinosa-Garcia & Langenheim, 1990 ;Fisher & Petrini, 1990 ;Rollinger & Langenheim, 1993 ;Rodrigues, 1994) illustrate that endophytes show a remarkable degree of similarity when compared over several dispersed sites, providing there is a geographic continuity of the hosts between the sites.…”

“…Petrini et al (1992) concluded that different plant tissues and organs may in fact resemble distinct microhabitats. Espinosa-Garcia & Langenheim (1990) expanded this concept by demonstrating that each individual of a host species may function as a distinct ecosystem.…”

“…Rodrigues (1994), however, found no significant difference between young and old leaves of immature palms. Frequency of colonization and\or species diversity has also been found to increase with the age of the organs or tissues in several hosts in temperate countries (Bernstein & Carroll, 1977 ;Carroll et al, 1977 ;Petrini & Carroll, 1981 ;Cabral, 1985 ;Sieber & Hugentobler, 1987 ;Bertoni & Cabral, 1988 ;Espinosa-Garcia & Langenheim, 1990 ;Carroll, 1991). This trend of increasing infection with increasing tissue age is thought to be due to repeated re-infection of host tissue over time from airborne endophytes, as opposed to outgrowth from a few initial infection sites Stone, 1987 ;Bertoni & Cabral, 1988).…”