Butković Anamarija, González Rubén, Rivarez Mark Paul Selda, Elena Santiago F
Instituto de Biología Integrativa de Sistemas (I2SysBio), CSIC-Universitat de València, Catedrático Agustín Escardino 9, Paterna, València 46980, Spain.
Virus Evol. 2021 Jun 30;7(2):veab063. doi: 10.1093/ve/veab063. eCollection 2021.
Viruses lie in a continuum between generalism and specialism depending on their ability to infect more or less hosts. While generalists are able to successfully infect a wide variety of hosts, specialists are limited to one or a few. Even though generalists seem to gain an advantage due to their wide host range, they usually pay a pleiotropic fitness cost within each host. On the contrary, a specialist has maximal fitness within its own host. A relevant yet poorly explored question is whether viruses differ in the way they interact with their hosts' gene expression depending on their degree of specialization. Using a genome-wide association study approach, we have identified host genes whose expression depends on whether hosts were infected with more or less specialized viral strains. Four hundred fifty natural accessions of were inoculated with strains with different past evolutionary histories and that shown different degrees of specialization. Three disease-related traits were measured and associated with different sets of host genes for each strain. The genetic architectures of these traits differed among viral strains and, in the case of the more specialized virus, also varied along the duration of infection. While most of the mapped loci were strain specific, one shared locus was mapped for both strains, a disease-resistance TIR-NBS-LRR class protein. Likewise, only putative cysteine-rich receptor-like protein kinases were involved in all three traits. The impact on disease progress of 10 selected genes was validated by studying the infection phenotypes of loss-of-function mutant plants. Nine of these mutants have altered the disease progress and/or symptoms intensity between both strains. Compared to wild-type plants six had an effect on both viral strains, three had an effect only on the more specialized, and two were significant during infection with the less specialized.
病毒处于泛化和特化的连续统一体中，这取决于它们感染宿主数量的多少。泛化病毒能够成功感染多种宿主，而特化病毒则局限于一种或少数几种宿主。尽管泛化病毒因其广泛的宿主范围似乎具有优势，但它们通常在每个宿主内付出多效性的适合度代价。相反，特化病毒在其自身宿主内具有最大适合度。一个相关但研究较少的问题是，病毒根据其特化程度与宿主基因表达相互作用的方式是否存在差异。我们采用全基因组关联研究方法，鉴定了那些表达取决于宿主感染的是特化程度较高还是较低的病毒株的宿主基因。用具有不同进化历史且特化程度不同的病毒株接种了450个自然种质。测量了三种与疾病相关的性状，并将其与每种病毒株的不同宿主基因集相关联。这些性状的遗传结构在病毒株之间存在差异，对于特化程度更高的病毒，其遗传结构在感染持续时间内也有所变化。虽然大多数定位的基因座是菌株特异性的，但两种病毒株都定位到了一个共同的基因座，即一种抗病TIR-NBS-LRR类蛋白。同样，只有假定的富含半胱氨酸的类受体蛋白激酶参与了所有三种性状。通过研究功能丧失突变体植物的感染表型，验证了10个选定基因对疾病进展的影响。其中9个突变体改变了两种病毒株之间的疾病进展和/或症状强度。与野生型植物相比，6个对两种病毒株都有影响，3个只对特化程度更高的病毒株有影响，2个在感染特化程度较低的病毒时具有显著影响。
