Single-stranded DNA multipartite viruses, which mostly consist of members of the genus Begomovirus, family Geminiviridae and all members of the family Nanoviridae, partly resolve the cost of genomic integrity maintenance through two remarkable capacities. They are able to systemically infect a host even when their genomic segments are not together in the same host cell, and these segments can be separately transmitted by insect vectors from host to host. These capacities potentially allow such viruses to reassort at a much larger spatial scale, since reassortants could arise from parental genotypes that do not co-infect the same cell or even the same host. To assess the limitations affecting reassortment and their implications in genome integrity maintenance, the objective of this review is to identify putative molecular constraints influencing reassorted segments throughout the infection cycle, and to confront expectations based on these constraints with empirical observations. Trans-replication of the reassorted segments emerges as the major constraint, while encapsidation, viral movement, and transmission compatibilities appear more permissive. Confronting the available molecular data and the resulting predictions on reassortments to field population surveys reveals notable discrepancies, particularly a surprising rarity of inter-specific natural reassortments within the Nanoviridae family. These apparent discrepancies unveil important knowledge gaps in the biology of ssDNA multipartite viruses and call for further investigation on the role of reassortment in their biology.

中文翻译：

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单链 DNA 多部分病毒的重配：通过现场观察对抗基于分子限制的期望

单链DNA多部分病毒主要由贝戈莫病毒属、双子病毒科和纳米病毒科的所有成员组成，通过两种卓越的能力部分解决了基因组完整性维护的成本。即使它们的基因组片段不在同一宿主细胞中，它们也能够系统性地感染宿主，并且这些片段可以通过昆虫载体在宿主之间单独传播。这些能力可能允许此类病毒在更大的空间尺度上重配，因为重配体可能来自不共感染同一细胞甚至同一宿主的亲代基因型。为了评估影响重配的限制及其对基因组完整性维护的影响，本综述的目的是确定影响整个感染周期重配片段的假定分子限制，并通过经验观察来应对基于这些限制的期望。重配片段的反式复制成为主要限制，而衣壳化、病毒运动和传播相容性似乎更为宽松。面对现有的分子数据和对现场种群调查的重配结果的预测，发现了显着的差异，特别是纳米病毒科内种间自然重配的罕见性令人惊讶。这些明显的差异揭示了 ssDNA 多部分病毒生物学中的重要知识差距，并需要进一步研究重配在其生物学中的作用。