Species composition of endophytic fungi in Amaranthus hybridus leaves, petioles, stems, and roots

Abstract

The objectives of this study were to identify and quantify fungi in asymptomatic, 5-mo-old Amaranthus hybridus plants grown in cultivated plots and in a greenhouse, and determine the species composition in different plant parts. Plants were sampled in South Africa from a plot at Potchefstroom in 1997, from two plots at Bloemfontein in 1997, and from one plot at Bloemfontein in 1996. Leaves, petioles, roots, stems, and seeds were collected, surface disinfested, and small sections were placed on corn-meal agar; seeds were not sectioned (9160 isolation attempts). All fungal colonies growing from the sections/seeds were transferred from colony margins onto separate agar plates and identified. Differences in species composition were found among plant parts (P<0.001). The most common species isolated from leaves and petioles at both sites and both years were species of the Alternaria tenuissima group. Fungal genera other than Alternaria predominated in the roots with pronounced differences between the two sites. Isolation frequencies from stems and seeds were low. This paper identifies the endophytic fungi found in A. hybridus and sets the stage for further studies dealing with these fungi.

Key Words:

• Alternaria tenuissima
• amaranth
• fungal ecology
• latent-infecting fungi