Videvall Elin, Paxton Kristina L, Campana Michael G, Cassin-Sackett Loren, Atkinson Carter T, Fleischer Robert C
Center for Conservation Genomics Smithsonian Conservation Biology Institute National Zoological Park Washington DC USA.
Present address: Hawai'i Cooperative Studies Unit University of Hawai'i at Hilo Hawai'i National Park HI USA.
Ecol Evol. 2021 Mar 27;11(9):4935-4944. doi: 10.1002/ece3.7401. eCollection 2021 May.
The malaria parasite (lineage GRW4) was introduced less than a century ago to the native avifauna of Hawai'i, where it has since caused major declines of endemic bird populations. One of the native bird species that is frequently infected with GRW4 is the Hawai'i 'amakihi (). To achieve a better understanding of the transcriptional activities of this virulent parasite, we performed a controlled challenge experiment of 15 'amakihi that were infected with GRW4. Blood samples containing malaria parasites were collected at two time points (intermediate and peak infection stages) from host individuals that were either experimentally infected by mosquitoes or inoculated with infected blood. We then used RNA sequencing to assemble a high-quality blood transcriptome of GRW4, allowing us to quantify parasite expression levels inside individual birds. We found few significant differences (one to two transcripts) in GRW4 expression levels between host infection stages and between inoculation methods. However, 36 transcripts showed differential expression levels among all host individuals, indicating a potential presence of host-specific gene regulation across hosts. To reduce the extinction risk of the remaining native bird species in Hawai'i, genetic resources of the local lineage are needed to enable further molecular characterization of this parasite. Our newly built Hawaiian GRW4 transcriptome assembly, together with analyses of the parasite's transcriptional activities inside the blood of Hawai'i 'amakihi, can provide us with important knowledge on how to combat this deadly avian disease in the future.
疟原虫（谱系GRW4）在不到一个世纪前被引入夏威夷的本地鸟类群落，自那时起，它已导致当地鸟类种群大幅减少。经常感染GRW4的本地鸟类物种之一是夏威夷绿雀（）。为了更好地了解这种致病寄生虫的转录活性，我们对15只感染GRW4的夏威夷绿雀进行了对照感染实验。在两个时间点（感染中期和高峰期）从通过蚊子实验感染或接种感染血液的宿主个体中采集含有疟原虫的血样。然后，我们使用RNA测序来组装高质量的GRW4血液转录组，从而能够量化单个鸟类体内的寄生虫表达水平。我们发现宿主感染阶段之间以及接种方法之间GRW4的表达水平几乎没有显著差异（一到两个转录本）。然而，36个转录本在所有宿主个体中显示出差异表达水平，表明在不同宿主之间可能存在宿主特异性基因调控。为了降低夏威夷剩余本地鸟类物种的灭绝风险，需要当地谱系的遗传资源来进一步对这种寄生虫进行分子特征分析。我们新构建的夏威夷GRW4转录组组装，以及对夏威夷绿雀血液中寄生虫转录活性的分析，能够为我们提供关于未来如何对抗这种致命禽类疾病的重要知识。
