Suppression of clonal reproduction in bulbous perennial herb Barnardia japonica sterilized by flower-smut fungi

Abstract

Flower-smut fungal infection has been widely observed in many plant species. As plants infected with flower-smut fungi exhibit visible changes in floral morphology and flower sterility, researchers have intensively studied the effects of the disease on sexual reproduction in host plants. Although most host plants are clonal perennials, the effects of flower-smut disease on clonal reproduction remain unclear. Here, we investigated the detrimental effects of flower-smut disease on clonal reproduction of a perennial host plant, Barnardia japonica. Barnardia japonica is a bulbous perennial and host of the flower-smut fungus Antherospora vaillantii. Diseased and healthy bulbs collected from fields at the end of the growing season were individually grown in pots for 1 year in a greenhouse, and their annual growth was analyzed, including offspring production. Survival, flowering probability, and the total bulb mass (i.e., the sum of a parent and its living offspring masses) at the end of the 1-year growth period and annual growth of the total bulb mass were comparable between diseased and healthy plants. We found a marked difference between diseased and healthy plants in the probability of clonal reproduction, which was 50% lower in diseased plants. Additionally, the number and mass of living offspring bulbs per parent were lower in diseased plants than in healthy plants. Our results indicate the detrimental effects of flower-smut disease on clonal reproduction in B. japonica, providing new insights into the effects of flower-smut disease on the reproduction of perennial host plants.