Endophytes isolated from three species of Protea in a nature reserve in the Western Cape, South Africa
Healthy leaves of three species of Protea, P. nitida, P. repens and P. neriifolia, were tested for endophytic fungi. Nine plants of each Protea species were sampled from a natural site which is ecologically undisturbed, other than from periodic bush fires. Leaves were sampled from the current flush (young leaves) and the previous year's flush (old leaves). After surface sterilisation, tissue was excised from the midrib (vein) and the leaf tissue either side of the midrib (intervein), plated on agar and all fungal colonies that developed were identified. Simple correspondence analysis showed that Protea repens and P. neriifolia had similar fungal endophyte assemblages, which differed from that of P. nitida. Significant differences in the numbers of isolates obtained from the different hosts, tissue types and tissue ages were demonstrated. Fewer fungi were isolated from young tissues by comparison with older tissues except in the case of P. nitida. Overall, fewer fungi were obtained from intervein tissues than from vein tissues. A much lower number of Botryosphaeria proteae isolates were obtained from P. nitida compared with the other two hosts. Botryosphaeria proteae is commonly associated with leaf tip dieback symptoms on P. repens. As this species proved to be the dominant taxon in the present study, isolates were tested for pathogenicity. No disease symptoms were observed thus suggesting that B. proteae could be a true endophyte, or at best a weakly opportunistic pathogen.