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Endophytes in sunflowers and other plants

Endophytes are microorganisms, fungal or bacterial, that live within plant tissues.  They may promote growth of plants by increasing nutrient availability. For example, nitrogen fixing bacteria have been identified in conifer needles. These bacteria may contribute to conifer survival in N-limited soils. Endophytes may also aid plants to withstand biotic and abiotic stresses. The advent of next generation sequencing (NGS) has revolutionized the field of plant-microbe associations and aided the identification of plant endophytes species since not all bacteria may be cultured in the laboratory.

We are interested in examining the endophytes in the California native sunflower species, Helianthus winteri, which has a limited distribution on the drought-prone south-facing foothills of the Southern Sierra Nevada and is phenologically and structurally distinct from the more common H. annuus (Stebbins et al. 2013). Several studies have examined root endophytes in H. annuus and reported that inoculation with certain bacteria increased stem and root growth. The endophyte populations of H. annuus and H. winteri have not been characterized. Our hypothesis is that there are differences in endophyte populations in the two species and that the endophytes may allow H. winterii to tolerate the warm dry locations better than H. annuus in which it is found.  Our  goal is to describe and compare the endophyte populations of H. winterii. We further hypothesize that endophytes may be partially responsible for the perennial life history of H. winterii. 

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