Department of Agronomy, Key Laboratory of Crop Germplasm Resource of Zhejiang Province, Zhejiang University, Hangzhou, 310058, China.
College of Agronomy, Hunan Agricultural University, Changsha, 410128, China.
Planta. 2022 Aug 27;256(4):64. doi: 10.1007/s00425-022-03982-4.
Stomatal density and guard cell length of 274 global core germplasms of rapeseed reveal that the stomatal morphological variation contributes to global ecological adaptation and diversification of Brassica napus. Stomata are microscopic structures of plants for the regulation of CO assimilation and transpiration. Stomatal morphology has changed substantially in the adaptation to the external environment during land plant evolution. Brassica napus is a major crop to produce oil, livestock feed and biofuel in the world. However, there are few studies on the regulatory genes controlling stomatal development and their interaction with environmental factors as well as the genetic mechanism of adaptive variation in B. napus. Here, we characterized stomatal density (SD) and guard cell length (GL) of 274 global core germplasms at seedling stage. It was found that among the significant phenotypic variation, European germplasms are mostly winter rapeseed with high stomatal density and small guard cell length. However, the germplasms from Asia (especially China) are semi-winter rapeseed, which is characterized by low stomatal density and large guard cell length. Through selective sweep analysis and homology comparison, we identified several candidate genes related to stomatal density and guard cell length, including Epidermal Patterning Factor2 (EPF2; BnaA09g23140D), Epidermal Patterning Factor Like4 (EPFL4; BnaC01g22890D) and Suppressor of LLP1 (SOL1 BnaC01g22810D). Haplotype and phylogenetic analysis showed that natural variation in EPF2, EPFL4 and SOL1 is closely associated with the winter, spring, and semi-winter rapeseed ecotypes. In summary, this study demonstrated for the first time the relation between stomatal phenotypic variation and ecological adaptation in rapeseed, which is useful for future molecular breeding of rapeseed in the context of evolution and domestication of key stomatal traits and global climate change.
274 份油菜全球核心种质的气孔密度和保卫细胞长度揭示了气孔形态变异有助于油菜的全球生态适应和多样化。气孔是植物调节 CO2 同化和蒸腾作用的微观结构。在陆地植物进化过程中，气孔形态在适应外部环境方面发生了很大变化。油菜是世界上生产油、牲畜饲料和生物燃料的主要作物。然而，关于控制气孔发育的调控基因及其与环境因素的相互作用以及油菜适应性变异的遗传机制的研究较少。在这里，我们对 274 份全球核心种质在幼苗期的气孔密度（SD）和保卫细胞长度（GL）进行了表征。结果发现，在显著的表型变异中，欧洲种质主要是冬油菜，具有较高的气孔密度和较小的保卫细胞长度。然而，来自亚洲（尤其是中国）的种质是半冬油菜，其特征是气孔密度低，保卫细胞长度大。通过选择扫描分析和同源比较，我们鉴定了几个与气孔密度和保卫细胞长度相关的候选基因，包括表皮图案因子 2（EPF2；BnaA09g23140D）、表皮图案因子样 4（EPFL4；BnaC01g22890D）和 LLP1 抑制物（SOL1 BnaC01g22810D）。单倍型和系统发育分析表明，EPF2、EPFL4 和 SOL1 的自然变异与冬、春、半冬油菜生态型密切相关。总之，这项研究首次证明了油菜气孔表型变异与生态适应之间的关系，这对于未来油菜在关键气孔性状的进化和驯化以及全球气候变化背景下的分子育种是有用的。
