Candida albicans is a commensal fungal species that commonly colonizes a heterogeneous mixture of human body where it intimately interacts with other microbes in the host environment such as the gastrointestinal (GI) tract. Most studies in fungal-bacterial interactions are about synergistic or antagonistic effects of bacterial functions on fungal physiological activities including pathogenicity. Very few studies have been demonstrated about the role of fungi on bacteria. In this study, we investigated the interactions between C. albicans and the bacterium Escherichia coli and unexpectedly observed that C. albicans enhances growth and proliferation of Escherichia coli strain K12 by facilitating its cell division. Importantly, we found, based on our genetic screens, that both fungus- and bacterium-derived factors, including the iron-responsive transcription factors Sef1 and Sfu1 in C. albicans and the siderophere enterobactin transporters FepD and FepG in E. coli, actively contribute to this transkingdom interaction. Deletion of SFU1 or SEF1 caused a dramatic reduction in growth enhancement of E. coli. Compared to the wild type E. coli, the enhanced growth of both fepD and fepG null mutants were largely dampened. However, the E. coli mutant lacking entB, a key enzyme catalyzing the biosynthesis of siderophore enterobactin, showed similar growth enhancement as the wild type when co-inoculated with C. albicans. C. albicans promotes growth and proliferation of the commensal bacterium E. coli and an iron-responsive signaling pathway appears to be required. C. albicans may act to supply a siderophere-like molecule that captures the environmental iron to promote the growth of E. coli. Our studies gave insight into a novel interacting mechanism operative in interspecies communication that occurs when bacteria and fungi co-exist.

白色念珠菌是一种常见的真菌物种，通常定居在人体的异质混合物中，在这里它与宿主环境（如胃肠道）中的其他微生物密切相互作用。关于真菌-细菌相互作用的大多数研究都涉及细菌功能对真菌生理活性（包括致病性）的协同或拮抗作用。关于真菌对细菌的作用的研究很少。在这项研究中，我们调查了白色念珠菌与大肠杆菌之间的相互作用，出乎意料地观察到白色念珠菌可增强大肠杆菌的生长和增殖。K12菌株通过促进其细胞分裂。重要的是，根据我们的遗传筛选，我们发现真菌和细菌衍生的因子，包括白色念珠菌中的铁响应转录因子Sef1和Sfu1，以及大肠杆菌中的人类肠杆菌素转运蛋白FepD和FepG，都起着积极的作用。与异族互动。SFU1或SEF1的删除导致大肠杆菌的生长增强显着降低。与野生型大肠杆菌相比，fepD和fepG null突变体的增强生长受到很大程度的抑制。但是，大肠杆菌突变体缺乏entB（一种催化铁载体肠杆菌素生物合成的关键酶），当与白色念珠菌共接种时，与野生型具有相似的生长促进作用。白色念珠菌可促进共生细菌大肠杆菌的生长和增殖，似乎需要铁应答信号通路。白色念珠菌可能起到提供类似siderophere的分子的作用，该分子捕获环境中的铁以促进大肠杆菌的生长。我们的研究为细菌和真菌共存时在种间交流中起作用的新型相互作用机制提供了见识。