The distribution of some fungal and bacterial endophytes in maize (Zea mays L.)

Abstract

SUMMARYEndophytic bacteria and fungi were isolated from healthy maize plants collected in a field in Devon. The average bacterial counts in the stem core tissues showed that the plant parts closer to the soil were more heavily colonized by bacteria than those near the top of the plants, and that the lower and middle part of the stems hosted the most frequently isolated bacterial species. Of the fungal species isolated, 12 had a relative importance of more than 10°o m the core, 15 in the epidermis, and only 5 in the leaves. In general the distribution patterns were different among the three tissue types studied, with core and epidermis of the stems showing almost equal colonization frequencies and the leaves being most heavily colonized. More fungal species were recovered from the core and epidermis of the stem than from the leaves. The fungi most frequently isolated showed some patterns of tissue specificity, with Alternaria alternata almost exclusively associated with the leaves and Aureobasidium pulhilans var. melanigerum most often present in the epidermal tissues.Assays showed low fungal colonization of seeds taken from freshly matured cobs and of seeds dried for 8 wk before testing, in contrast to higher colonization frequencies observed for the seeds used for planting. The mean values for fungal isolations in the stem pieces mostly in contact with the soil flora or close to the ground were lower than those of the more centrally placed sections. These areas of low fungal infection yielded the highest bacteriai counts. The potential role of bacterial endophytes in biological control is briefly discussed.

Rice Seeds as Sources of Endophytic Bacteria

“…In general, endophytic bacteria colonize the intercellular spaces and vascular systems of host plants, with only a few reports of intracellular colonization (9). Since endophytic bacteria are considered to compete with each other and with other endophytic organisms (such as fungi) for the limited space within the host plant (5,33), the endophytic bacteria that reside in seeds may have the advantage of being able to infect rapidly the next generation of plants.…”

Endophytic microorganisms: a review on insect control and recent advances on tropical plants

“…In maize, although nitrogen-fixing diazotrophic bacteria from the tropics have already been isolated as cited above, other endophytic bacteria studies with this host come from temperate regions (Fisher et al, 1992). Souza (1996) obtained 189 bacterial isolates from two populations of Zea mays and a hybrid between them, from two localities in Brazil.…”

“…However, Acremonium-like fungi were isolated only from leaf sheats of the first species. Although endophytic fungi had already been isolated from maize ( Zea mays), these endophytes were obtained from temperate regions (Fisher et al, 1992). A series of investigations were carried out, starting with the isolation of endophytic fungi from populations of Z. mays hybrids from tropical regions.…”

Influence of an endophytic fungus on host plant selection by a polyphagous moth via volatile spectrum changes

“…Among the least studied taxa of plant-associated fungal endophytes are the unspecialized, widespread soil-borne fungal endophytes belonging to the genus Acremonium. Species of this genus are commonly reported when investigating endophyte communities in plants (McGee et al 1991;Fisher et al 1992;Colllado et al 1999;Kumaresan and Suryanarayanan 2001;Wicklow et al 2005). Unlike the clavicipitaceous fungal endophytes of grasses, these endophytes are transmitted horizontally by spores (Gams 1991), are predominantly restricted to the root systems of host plants (Schulz et al 1993), show no symptoms of infection (Bargmann and Schönbeck 1992;Raps 1997), and are commonly found in studies screening for endophyte diversity (Schulz et al 1993;Gange et al 2007).…”