Mutualism within a simulated microgravity environment; Piriformospora indica promotes the growth of Medicago truncatula.

Martin W Hayes, Gary W Stutte, Michelle Mc Keon-Bennett, Patrick G Murray


The endophytic fungus Piriformospora indica developed a sub epidermal infection within Medicago truncatula at 1g and at simulated micro gravity (µg) over a period of 15 days, resulting in intracellular colonization of mature host tissue. At 1g P. indica inoculation affected the growth and morphology of M. truncatula, predominantly roots. Inoculated M. truncatula had a significantly greater number of roots (102%), total root length (88%), and dry root weight (25%) than non-inoculated plants. Effects on shoot morphology of P. indica inoculated M. truncatula included longer (31%) and heavier (30%) shoots, along with increased leaf surface area (98%). P. indica retained the ability to promote the growth of M. truncatula under simulated µg conditions upon two dimensional clinostatic rotation, significantly increasing root number by 51% and root length by 48%. These physiological and morphological changes may mitigate biotic and abiotic stresses that would otherwise limit crop productivity.


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