Henon bamboo flowering recorded first time in 120 years revealed how Aciculosporium take affects the floral organs of the host

Flowering of Henon bamboo (Phyllostachys nigra var. henonis) was observed in Japan in 2020s. We estimated that the observation of flowering was recorded for the first time in 120 y. Additionally, stromata of Aciculosporium take have also been observed in the flower buds, or spikelets, of Henon bamboo. Aciculosporium take usually forms stromata at the vegetative shoot apex, which presumably originated from ancestral pathogens affecting floral tissues. However, given the infrequent occurrence of bamboo flowering events, it is unclear whether A. take still retains the ability to colonize ovaries of flowers. To ascertain the location where the fungus forms stromata, anatomical and histological analyses were performed. Because flower buds, including floral organs, are fragile, tissue sections were prepared by adhering them to cellophane tape, and subsequently examined using a triple fluorescent staining method. The findings showed that the fungus did not invade the ovaries but formed stromata from the apical rudimentary floret within the flower buds.