Coastal Salinity Tolerant Grass Engineering and Technology Research Center, Ludong University, Yantai, Shandong, China.
BMC Plant Biol. 2022 Jul 21;22(1):355. doi: 10.1186/s12870-022-03752-0.
Zoysiagrass (Zoysia spp.) is a warm-season turfgrass. It is widely used as turfgrasses throughout the world, offers good turf qualities, including salt tolerance, resistance to drought and heat. However, the underlying genetic mechanism of zoysiagrass responsive to salt stress remains largely unexplored.
In present study, we performed a whole-genome comparative analysis for ten plant genomes. Evolutionary analysis revealed that Chloridoideae diverged from Panicoideae approximately 33.7 million years ago (Mya), and the phylogenetic relationship among three zoysiagrasses species suggested that Zoysia matrella may represent an interspecific hybrid between Zoysia japonica and Zoysia pacifica. Genomic synteny indicated that Zoysia underwent a genus-specific whole-genome duplication (WGD) event approximately 20.8 Mya. The expression bais of homologous genes between the two subgenomes suggested that the B subgenome of Z. japonica contributes to salt tolerance. In additon, comparative genomic analyses revealed that the salt adaptation of Zoysia is likely attributable to the expanded cytochrome P450 and ABA biosynthetic gene families. Furthermore, we further found that many duplicated genes from the extra WGD event exhibited distinct functional divergence in response to salt stress using transcriptomic analysis, suggesting that this WGD event contributed to strong resistance to salt stress.
Here, our results revealed that expanded cytochrome P450 and ABA biosynthetic gene families, and many of those duplicated genes from recent zoysia-specific WGD event contributed to salt adaptation of zoysiagrass, which provided insight into the genetic underpinning of salt adaptation and valuable information for further studies on salt stress-related traits in Zoysia.
结缕草（Zoysia spp.）是一种暖季型草坪草。它被广泛用作世界各地的草坪草，具有良好的草坪品质，包括耐盐性、抗旱性和耐热性。然而，结缕草对盐胁迫响应的潜在遗传机制在很大程度上仍未被探索。
在本研究中，我们对十个植物基因组进行了全基因组比较分析。进化分析表明，Chloridoideae 大约在 3370 万年前从 Panicoideae 分化出来，而三个结缕草种的系统发育关系表明，糙叶结缕草可能是结缕草和中华结缕草的种间杂种。基因组同线性表明，结缕草大约在 2080 万年前经历了一次属特异性的全基因组加倍（WGD）事件。两个亚基因组之间同源基因的表达偏倚表明，Z. japonica 的 B 亚基因组有助于耐盐性。此外，比较基因组分析表明，结缕草的耐盐性可能归因于细胞色素 P450 和 ABA 生物合成基因家族的扩展。此外，我们还发现，通过转录组分析，来自额外 WGD 事件的许多重复基因在响应盐胁迫时表现出明显的功能分化，表明该 WGD 事件有助于对盐胁迫的强烈抗性。
本研究结果表明，扩展的细胞色素 P450 和 ABA 生物合成基因家族，以及来自最近结缕草特异性 WGD 事件的许多重复基因，有助于结缕草对盐胁迫的适应，这为盐适应的遗传基础提供了深入了解，并为进一步研究结缕草与盐胁迫相关性状提供了有价值的信息。
