A Yale-led research team has found that tree seedlings grew less effectively in soil located below their mother tree than in soil found under a different individual of the same species. After ruling out other potential drivers, they concluded that the differences in growth were most likely due to microbial pathogens that specialize at the genotype level. Theoretical models revealed that such highly specialized pathogens could help maintain diversity in tree communities and promote increased seed dispersal over evolutionary timescales.
“We often think of pathogens as pests,” said Jenalle Eck
, a postdoctoral researcher at the University of Zurich and a former visiting doctoral student at the Yale School of Forestry & Environmental Studies (F&ES), “but we’re finding that they play a key role in a highly diverse ecosystem.”
The study was published in the Proceedings of the National Academy of Sciences
. The senior author of the paper was Liza Comita
, an assistant professor of tropical forest ecology at F&ES.
For the study, Eck conducted a shadehouse experiment, potting more than 200 seedlings of the tropical tree Virola surinamensis
grown from seeds collected in a diverse tropical forest in Panama. The soil for the pots was sourced from either the seedlings’ maternal tree or other trees of the same species.
The researchers showed that the difference in performance between seedlings growing in “maternal” soil and “non-maternal” soil was not the result of variations in soil nutrients or beneficial symbiotic relationships with fungi, thanks to lab work conducted at Yale by Camille Delavaux ’16 M.E.Sc.,
currently a doctoral student at the University of Kansas.