Geographic distribution patterns of vertically transmitted endophytes in two native grasses in Argentina

LEOPOLDO J. IANNONE, PATRICIA D. MC CARGO, LILIANA M. GIUSSANI, AND CHRISTOPHER L. SCHARDL

SYMBIOSIS

SPRINGER

Lugar: Berlin; Año: 2013 p. 99 - 110

0334-5114

The incidence of epichloid endophytes in populationsof wild grasses is usually variable, and the knowledgeabout distribution patterns and how environmental factorsaffect such an incidence is limited. Here we performed a broadscale survey data to study whether the distribution patternsand the incidence of vertically-transmitted endophytes in populationsof two native grasses from South-America, Poa lanuginosaPoir. and Poa bonariensis (Lam.) Kunth., areassociated with environmental characteristics. We also characterizedthe endophytes from different populations to establishif the genotype of the endophytes is also correlated withenvironmental variables. The incidence of endophytes rangedfrom 0 to 100 % in both host species. In P. lanuginosa,endophytes were only found in populations on sandy coastaldunes and their incidence was positively associated withwinter regime rainfall and soil water availability in the growingseason. In P. bonariensis, endophytes were only found inpopulations in xerophytic forests and their incidence washighly associated with plant community. The distributions ofinfested populations suggested that the endophytes are notfound in those areas with the most favorable or most stressinggrowth conditions accordingly to climatic or edaphical characteristics.Only the vertically transmitted hybrid endophytespecies Neotyphodium tembladerae was detected in both hostspecies. Under the hypothesis of vertical transmission, theseresults suggested that the endophyte should have been lost inendophyte free populations but is maintained in populationsestablished in environments presenting moderate stress assalinity or short drought periods.