Massive tandem proliferation of ELIPs supports convergent evolution of desiccation tolerance across land plants

First author: Robert VanBuren; Affiliations: Michigan State University (密歇根州立大学): East Lansing, USA

Corresponding author: Robert VanBuren

Desiccation (干燥、脱水) tolerance was a critical adaptation for the colonization of land by early non-vascular plants. Resurrection (复苏) plants have maintained or rewired these ancestral protective mechanisms and desiccation-tolerant species are dispersed across the land plant phylogeny. Though common physiological, biochemical, and molecular signatures are observed across resurrection plant lineages, features underlying the recurrent evolution of desiccation tolerance are unknown. Here we used a comparative approach to identify patterns of genome evolution and gene duplication associated with desiccation tolerance. We identified a single gene family with dramatic expansion in all sequenced resurrection plant genomes and no expansion in desiccation-sensitive species. This gene family of early light-induced proteins (ELIPs) expanded in resurrection plants convergent through repeated tandem gene duplication. ELIPS are universally highly expressed during desiccation in all surveyed resurrection plants and may play a role in protecting against photooxidative (光氧化) damage of the photosynthetic apparatus (光合器官) during prolonged (延长的) dehydration. Photosynthesis is particularly sensitive to dehydration and the increased abundance of ELIPs may help facilitate the rapid recovery observed for most resurrection plants. Together, these observations support convergent evolution of desiccation tolerance in land plants through tandem gene duplication.

耐脱水性是早期非维管植物殖民陆地的重要适应过程。复苏植物保留或者重新获得了这些古老的保护性机制，耐脱水性植物在整个陆地植物分类系统中具有分布。尽管，对着复苏植物已经进行了常规的生理、生化及分子方面的研究，然而对于耐脱水性的反复演化还不是很清楚。本文，作者通过比较分析鉴定了与耐脱水性相关的基因组演化和基因复制模式。作者鉴定到了一个基因家族在所有的复苏植物中均有剧烈的扩张，而在脱水敏感的物种中没有扩张。早期光诱导蛋白ELIP基因家族在复苏植物中均通过重复的串联基因复制发生扩张。ELIP在所有调查的复苏植物脱水过程中均会高表达，可能在长时间脱水过程中保护光合器官免受光氧化的伤害。光合作用对于脱水十分敏感，大多数复苏植物中ELIP基因家族成员的增加可能有利于促进快速恢复。综上，本文的研究揭示了陆地植物通过串联基因复制协同演化出耐脱水性。

doi: https://doi.org/10.1104/pp.18.01420

Journal: Plant Physiology

First Published: 02 January, 2019