Transcriptional variation in malaria parasites: why and how.

Oriol Llorà-Batlle,Elisabet Tintó-Font,Alfred Cortés

doi:10.1093/bfgp/elz009

Abstract

Transcriptional differences enable the generation of alternative phenotypes from the same genome. In malaria parasites, transcriptional plasticity plays a major role in the process of adaptation to fluctuations in the environment. Multiple studies with culture-adapted parasites and field isolates are starting to unravel the different transcriptional alternatives available to Plasmodium falciparum and the underlying molecular mechanisms. Here we discuss how epigenetic variation, directed transcriptional responses and also genetic changes that affect transcript levels can all contribute to transcriptional variation and, ultimately, parasite survival. Some transcriptional changes are driven by stochastic events. These changes can occur spontaneously, resulting in heterogeneity within parasite populations that provides the grounds for adaptation by dynamic natural selection. However, transcriptional changes can also occur in response to external cues. A better understanding of the mechanisms that the parasite has evolved to alter its transcriptome may ultimately contribute to the design of strategies to combat malaria to which the parasite cannot adapt.

Highlights

Differences among the individuals of a microbial population are essential for their survival in changing environments, as diversity provides the grounds for dynamic natural selection when the conditions of the environment fluctuate
This include changes in temperature associated with fever episodes, changes in nutrient availability associated with the metabolic or nutritional state of the host, changes in erythrocyte properties associated with host genetic traits, or changes in host immunity, among others
Optimal fitness of the majority of individuals is favored in some multicellular higher eukaryotes such as humans, but it is of little importance in microbial communities with population sizes several orders of magnitude higher

Summary

Introduction

Differences among the individuals of a microbial population are essential for their survival in changing environments, as diversity provides the grounds for dynamic natural selection when the conditions of the environment fluctuate. The intrinsic heterogeneity in the expression of these genes, which precedes unpredictable environment changes, results in phenotypic variation within parasite populations, providing a substrate for natural selection.

Results

Conclusion