At 7h post-inoculation, we observed a mixed population of red and green mitochondria in the appressorium and apical cell, while photoconverted mitochondrial decreases in the distal and middle cells. (10/13)

We found the volume of mitochondria in the appressorium was greater than the starting average mitochondrial the apical conidial cell at 0h. This observation suggests de novo biogenesis during appressorium maturation. (9/13)

We investigated whether autophagy is required for organelle breakdown in conidial cells. Using a ∆atg8:Scad2-paGFP strain lacking autophagy, we found that only the apical cell transported mitochondria to the appressorium, while those in distal and middle cells remained intact. (8/13)

We next asked whether the three-celled conidium of M. oryzae uniformly contributes organelles to the appressorium. Using paGFP-tagged mitochondria, we found that only the apical cell transfers intact mitochondria to the appressorium. The distal and middle cells retain their photoactivated signal 7/

Our observations provide evidence that the three-celled conidium is an open system that facilitates trafficking from all cells to the appressorium. However, conidium-appressorium connectivity is transient. By 6 hpi, cytoplasmic streaming into the appressorium ceases.(6/13)

Given that filamentous fungi possess septal pores for intercellular exchange, we asked whether the conidium behaves as an open system. Photoactivation experiments confirmed rapid cytoplasmic diffusion across cells and into the appressorium, indicating open septal pores early in development. (5/13)

To quantify these changes, we modeled fluorescence intensity over time. The distal and middle cells showed a rapid linear decrease in organelle signal, while the apical cell retained organelles longer, correlating with a steady increase in the appressorium—suggesting directional trafficking. (4/13)

Using 4D live-cell imaging, we observed a continuous influx of organelles from the conidium into the growing appressorium, accompanied by a decline in organelle abundance within the conidial cells (3/13)

To carry out the investigation, first we fluorescently tagged 10 organelle proteins with eGFP in M. oryzae to track their fate, and confirmed that vector integration didn't affect pathogenicity (2/13)