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ARS Home » Midwest Area » Lexington, Kentucky » Forage-animal Production Research » Research » Publications at this Location » Publication #281097
Title: Tall fescue endophyte effects on tolerance to water-deficit stress

Author
item NAGABHYRU, PADMAJA - University Of Kentucky
item Dinkins, Randy
item WOOD, CONSTANCE - University Of Kentucky
item Bacon, Charles
item SCHARDL, CHRISTOPHER - University Of Kentucky

Submitted to: BMC Plant Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2013
Publication Date: 9/9/2013
Citation: Nagabhyru, P., Dinkins, R.D., Wood, C.L., Bacon, C.W., Schardl, C.L. 2013. Tall fescue endophyte effects on tolerance to water-deficit stress. Biomed Central (BMC) Plant Biology. 13:127.

Interpretive Summary: To understand more about the enhanced drought tolerance conferred by the endophyte Neotyphodium coenophialum in tall fescue, we analyzed the effect of the endophyte on genetically identical tall fescue clones with (E+) and without the endophyte (E-), by generating E- plants through fungicide treatment of E+ plants and selectively propagating single tillers. Time course studies were conducted in which water was withheld from 0 to 5 days, and endophyte effects were investigated on sugars, sugar alcohols, and amino acids, as well as some of the major fungal metabolites levels in two tall fescue clone pairs. Upon re-watering, survival and re-tillering was significantly greater for E+ than E- plants starting from day 2 or 3 of the treatment. Endophyte effects on free sugars and amino acids in shoot and root were evident within two days of the onset of drought stress. Loline alkaloids and mannitol, which are endophyte metabolites, also significantly increased with drought stress. Thus it appears that the endophyte aids in survival and recovery of plants from drought, and may act in part by inducing rapid accumulation of compatible solutes soon after imposition of stress.

Technical Abstract: To understand more about the enhanced drought tolerance conferred by the endophyte Neotyphodium coenophialum in tall fescue, we analyzed the effect of the endophyte on genetically identical tall fescue clones with (E+) and without the endophyte (E-), by generating E- plants through fungicide treatment of E+ plants and selectively propagating single tillers. We conducted time course studies in which water was withheld from 0 to 5 days, and investigated endophyte effects on changes in levels of sugars, sugar alcohols, and amino acids, as well as some major fungal metabolites in two clone pairs of tall fescue. Upon re-watering, survival and re-tillering was significantly greater for E+ than E- plants starting from day 2 or 3 of the treatment. Endophyte effects on free sugars and certain amino acids in shoot and root were evident within two days of the onset of drought stress. Loline alkaloids and mannitol, which are endophyte metabolites, also significantly increased with drought stress. In the second genotype, similar effects of endophyte on survival and retillering were also observed, but of lesser magnitude than with the first genotype. Thus it was concluded that endophyte aids in survival and recovery of plants from drought, and may act in part by inducing rapid accumulation of these compatible solutes soon after imposition of stress.