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Endophyte-mediated adjustments in host morphology and physiology and effects on host fitness traits in grasses

Author:
Torres, Mónica S., White Jr., James F., Zhang, Xin, Hinton, Dorothy M., Bacon, Charles W.
Source:
Fungal ecology 2012 v.5 no.3 pp. 322
ISSN:
1754-5048
Subject:
antioxidant activity, auxins, biotic stress, cell death, disease resistance, drought tolerance, endophytes, grasses, hosts, metal tolerance, mycelium, oxidative stress, plant development, plant growth, plant tissues, reactive oxygen species, secretion, symbiosis
Abstract:
Endophytic fungi have been shown to increase tolerance of hosts to biotic and abiotic stresses and in some cases alter growth and development of plants. In this article we evaluate some effects that clavicipitaceous endophytes have on development and physiology of plant tissues. We postulate that oxidative stress protection is the fundamental underlying benefit conferred by many endophytes, accounting for frequently observed enhanced disease resistance, drought tolerance, heavy metal tolerance and tolerance to numerous additional oxidative stresses. We hypothesize that endophyte-mediated oxidative stress protection of the host is the result of at least two processes, including: (1) secretion of reactive oxygen species (ROS) from endophytic mycelia into plant cells; and (2) secretion of auxin from endophytic mycelia into plant cells. Both processes result in an increase in ROS in plant tissues; and stimulate plant tissues to increase activities of antioxidant systems. Auxin is suggested to function in suppression of plant cell death and may be important in maintaining the endophyte–plant symbiosis.
Agid:
56786
Handle:
10113/56786