Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen 361102, Fujian, China.
Novogene Co. Ltd, Building 301, Zone A10 Jiuxianqiao North Road, Chaoyang District, Beijing 100006, China.
Curr Biol. 2024 Aug 19;34(16):3707-3721.e7. doi: 10.1016/j.cub.2024.07.010. Epub 2024 Jul 29.
Vivipary is a prominent feature of mangroves, allowing seeds to complete germination while attached to the mother plant, and equips propagules to endure and flourish in challenging coastal intertidal wetlands. However, vivipary-associated genetic mechanisms remain largely elusive. Genomes of two viviparous mangrove species and a non-viviparous inland relative were sequenced and assembled at the chromosome level. Comparative genomic analyses between viviparous and non-viviparous genomes revealed that DELAY OF GERMINATION 1 (DOG1) family genes (DFGs), the proteins from which are crucial for seed dormancy, germination, and reserve accumulation, are either lost or dysfunctional in the entire lineage of true viviparous mangroves but are present and functional in their inland, non-viviparous relatives. Transcriptome dynamics at key stages of vivipary further highlighted the roles of phytohormonal homeostasis, proteins stored in mature seeds, and proanthocyanidins in vivipary under conditions lacking DFGs. Population genomic analyses elucidate dynamics of syntenic regions surrounding the missing DFGs. Our findings demonstrated the genetic foundation of constitutive vivipary in Rhizophoraceae mangroves.
胎生是红树林的一个显著特征，允许种子在附着于母株时完成发芽，并使繁殖体能够在具有挑战性的沿海潮间湿地中生存和繁衍。然而，与胎生相关的遗传机制在很大程度上仍难以捉摸。对两个胎生红树林物种和一个非胎生内陆亲缘种的基因组进行了测序和染色体水平组装。胎生与非胎生基因组之间的比较基因组分析表明，延迟萌发 1 型（DOG1）家族基因（DFGs）的蛋白质对于种子休眠、萌发和储备积累至关重要，在真正胎生红树林的整个谱系中要么丢失要么功能失调，但在它们的内陆非胎生亲缘种中存在且功能正常。胎生关键阶段的转录组动态进一步强调了在缺乏 DFG 的情况下，植物激素稳态、成熟种子中储存的蛋白质和原花青素在胎生中的作用。种群基因组分析阐明了缺失 DFG 周围同源区域的动态。我们的研究结果证明了 Rhizophoraceae 红树林中胎生的遗传基础。
