Biomolecules Generated During Programmed Cell Death (PCD) Enhance the Capacity of Proliferating Ustilago maydis Cells to Overcome the Negative Impacts of Non-PCD Necromass.

This work builds upon our previous “repopulation upon shattering” (RUS) studies in the yeast-like microbe Ustilago maydis, focusing mainly on a deeper understanding of the suicidal type of death caused by self-generated hypoxia (SGH). The key findings are: (1) the massive loss of viability induced by SGH occurs via programmed cell death (PCD), (2) the PCD-released materials are more beneficial for the surviving cells than the nutrients liberated from cells that die through necrotic processes, (3) products of PCD can stimulate growth even in the presence of growth-suppressive necromass, (4) the beneficial effects of substances released through PCD extend to two other species within the family Ustilaginaceae, and (5) U. maydis exhibited a remarkable ability to withstand the negative effects of non-PCD necromass. The third and fifth points are of special note. The third indicates that PCD-derived materials are essential for critical initial regrowth in post-stress environments where there is a high presence of non-PCD necromass. As the revitalized population strengthens, it would correspondingly enhance the communal ability to exploit more challenging nutrients. The robust resilience of U. maydis survivors against non-PCD necromass could represent an important fitness determinant, mediating competitive success in mixed microbial communities where non-PCD necromass imposes selective pressure. Thus, while providing valuable insights, the study also underscores the need for further research, especially in understanding the molecular underpinnings of the RUS phenomenon.