College of Forestry, Shandong Agricultural University, Taian 271018, China.
State Forestry and Grassland Administration Key Laboratory of Silviculture in the Downstream Areas of the Yellow River, Shandong Agricultural University, Taian 271018, China.
Gigascience. 2022 Dec 28;12. doi: 10.1093/gigascience/giad053. Epub 2023 Jul 26.
The woody halophyte Tamarix chinensis is a pioneer tree species in the coastal wetland ecosystem of northern China, exhibiting high resistance to salt stress. However, the genetic information underlying salt tolerance in T. chinensis remains to be seen. Here we present a genomic investigation of T. chinensis to elucidate the underlying mechanism of its high resistance to salinity.
Using a combination of PacBio and high-throughput chromosome conformation capture data, a chromosome-level T. chinensis genome was assembled with a size of 1.32 Gb and scaffold N50 of 110.03 Mb. Genome evolution analyses revealed that T. chinensis significantly expanded families of HAT and LIMYB genes. Whole-genome and tandem duplications contributed to the expansion of genes associated with the salinity adaptation of T. chinensis. Transcriptome analyses were performed on root and shoot tissues during salt stress and recovery, and several hub genes responding to salt stress were identified. WRKY33/40, MPK3/4, and XBAT31 were critical in responding to salt stress during early exposure, while WRKY40, ZAT10, AHK4, IRX9, and CESA4/8 were involved in responding to salt stress during late stress and recovery. In addition, PER7/27/57/73 encoding class III peroxidase and MCM3/4/5/7 encoding DNA replication licensing factor maintained up/downregulation during salt stress and recovery stages.
The results presented here reveal the genetic mechanisms underlying salt adaptation in T. chinensis, thus providing important genomic resources for evolutionary studies on tamarisk and plant salt tolerance genetic improvement.
木本盐生植物柽柳是中国北方滨海湿地生态系统中的先锋树种，具有很强的耐盐能力。然而，柽柳耐盐性的遗传信息尚不清楚。本研究对柽柳进行了基因组研究，以阐明其高耐盐性的潜在机制。
利用 PacBio 和高通量染色体构象捕获数据相结合的方法，组装得到了一个大小为 1.32 Gb、支架 N50 为 110.03 Mb 的柽柳染色体水平基因组。基因组进化分析表明，柽柳 HAT 和 LIMYB 基因家族显著扩张。全基因组和串联重复导致了与柽柳耐盐性相关基因的扩张。对盐胁迫和恢复过程中根和茎组织的转录组进行了分析，鉴定出了几个响应盐胁迫的枢纽基因。WRKY33/40、MPK3/4 和 XBAT31 在早期暴露时对盐胁迫的响应至关重要，而 WRKY40、ZAT10、AHK4、IRX9 和 CESA4/8 则参与了晚期胁迫和恢复过程中对盐胁迫的响应。此外，编码 III 类过氧化物酶的 PER7/27/57/73 和编码 DNA 复制许可因子的 MCM3/4/5/7 在盐胁迫和恢复阶段保持上调/下调。
本研究结果揭示了柽柳适应盐胁迫的遗传机制，为柽柳进化研究和植物耐盐性遗传改良提供了重要的基因组资源。
