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Title: DO NEOTYPHODIUM-ENDOPHYTES AFFECT COPPER ACQUISITION BY COOL-SEASON GRASSES?

Author
item MALINOWSKI, D - TEXAS A&M UNIVERSITY
item Belesky, David
item ZUO, H - TEXAS A&M UNIVERSITY
item Ruckle, Joyce
item ALLOUSH, G - TISHREEN UNIV, SYRIA
item STRATTON, A - AGRESEARCH, NZ

Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: 7/1/2003
Publication Date: 12/15/2003
Citation: Malinowski, D.P., Belesky, D.P., Zuo, H., Ruckle, J.M., Alloush, G.A., Stratton, A.E. 2003. Do neotyphodium-endophytes affect copper acquisition by cool-season grasses?. In Annual Meeting Abstracts (CD-ROM). ASA, CSSA, and SSSA, Madison, WI.

Interpretive Summary:

Technical Abstract: Copper (Cu) concentration in tall fescue (Festuca arundinacea Schreb.) forage may be reduced in response to infection with endemic N. coenophialum-endophytes, resulting in low serum-Cu and immune-related disorders in grazing animals. We hypothesized a mechanism of Cu immobilization by root exudates of endophyte-infected grasses. Tall fescue varieties Grasslands Flecha and Jesup infected with a novel, non ergot producing endophyte strain AR542, perennial ryegrass (Lolium perenne L.) varieties Aries and Quartet infected with a novel, non lolitrem B producing strain AR1, and their noninfected (E-) forms were grown in nutrient solutions at 1.0 (P+) and 0.0 mM (P-) phosphorus concentrations. The Cu2+-binding activity of extracellular root exudates, and concentrations of Cu and other heavy metals in roots and shoots were measured. In response to P deficiency in nutrient solution, extracellular root exudates of AR542-infected tall fescue had higher Cu2+-binding activity (i.e., lower concentration of free Cu2+) then E- plants (0.096 vs. 0.188 'M Cu2+ g-1 root DM, respectively). In contrast, Cu2+-binding activity of root exudates of perennial ryegrass was not affected by endophyte infection, but was also higher in P- vs. P+ nutrient solution (0.068 vs. 0.114 'M Cu2+ g-1 root DM). The mechanism of Cu2+-binding by extracellular root exudates was not related to Cu concentrations in shoots of both grasses. The Cu2+-binding activity of extracellular root exudates may affect Cu accumulation by field-grown, endophyte-infected tall fescue under P-limiting growth conditions.