P335 Genome plasticity in Candida albicans : acutting-edge strategy for evolution, adaptation, and survival
Authors: Mba Ifeanyi , Nweze Emeka Innocent 
Published: September 2022

Abstract

Poster session 3, September 23, 2022, 12:30 PM - 1:30 PM

Objectives
Candida albicans is the most implicated fungal species that grows as a commensal or opportunistic pathogen in the human host. The genome plasticity is central to its adaptation and has long been of considerable interest. Understanding the factors that affect the genome is crucial for a proper understanding of species and rapid development and adjustment of therapeutic strategies to mitigate their spread.

Methods
Here, we present an up-to-date overview of recent genomic studies involving C. albicans and discuss the accumulating evidence that shows how mitotic recombination events, ploidy dynamics, aneuploidy, and loss of heterozygosity (LOH) influence evolution, adaptation, and survival in C. albicans. This review was exclusively based on a thorough literature review on research papers investigating C. albicans and its genome. The Boolean search for relevant literatures was performed in Google scholar, Science direct, PubMed, and Web of science using a combination of the following precise keywords: Candida albicans, Genome plasticity, Parasexual events, Ploidy dynamics, Aneuploidy, LOH, and Mutations. All the papers that relate to the genome and genetics of C. albicans were included in the study.

Results
Candida albicans has a diploid heterozygous genome that is highly dynamic and can display variation from small to large-scale chromosomal rearrangement and aneuploidy, which have implications for drug resistance, virulence, and pathogenicity. The instability in the genome arising from stress or exposure to the host environment can be detrimental to survival. However, C. albicans can tactically exploit this instability in their genome as a survival strategy. Our investigation showed that there is a need for more studies to understand the regulation and the exact mechanisms that lead to chromosomal instability in C. albicans. It is important to understand how increasing ploidy affects genome stability. It is also important to unravel how tetraploids lose chromosomes to revert to diploids. Whether other ploidy states can be efficiently sustained also remains to be unraveled. Moreover, as the understanding of the pathogenicity of fungi continues to evolve, there is a continuing challenge in grasping the processes and factors that mediate the switching from commensal to the pathogen. It remains unclear whether parasexual processes also operate within natural populations. More studies are needed to appreciate better parasexual recombination events and mutational processes in C. albicans evolution and its link to persistence and infection establishment. The interrelationship between the host and the microbes can promote microbial fitness in the host and help the host acquire some beneficial features such as resistance against several pathogens. However, the long-term consequences on host fitness are largely unknown. This evidence provides an avenue to study evolutionary forces controlling C. albicans fitness level after host exposure.

Conclusion
The variation in the genome of C. albicans greatly influences its biology, stress response approaches, and its virulence and resistant potentials. Understanding how C. albicans generate diversity is very crucial as this will help to design strategies mitigating their spread.