Ma Ziyan, Chen Si, Wang Zhizhi, Liu Jianxiu, Zhang Bing
College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China.
Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing 210014, China.
J Proteomics. 2021 Jun 15;241:104245. doi: 10.1016/j.jprot.2021.104245. Epub 2021 Apr 24.
As an important perennial warm-season turfgrass species, bermudagrass (Cynodon dactylon L.) forms underground-growing rhizomes and aboveground-growing stolons simultaneously, making it a fast propagating clonal plant with strong regeneration ability. In the current study, we compared the internode proteomes of rhizomes and stolons at the same developmental stage in the bermudagrass cultivar Yangjiang using iTRAQ. The results indicated that 228 protein species were differentially accumulated in the two specialized stems. In agreement with the different contents of starch, chlorophyll, anthocyanin and HO in the two types of stems, photosynthesis and flavonoid biosynthesis were enriched with differentially accumulated protein species (DAPs) in stolons, whereas starch and sucrose metabolism, glycolysis, and HO metabolism were enriched with DAPs in rhizomes. Burying stolons in the soil resulted in the gradual degradation of chlorophyll and anthocyanin, accumulation of starch, and increment of HO, which is similar to the physiological characteristics of rhizomes. These results collectively revealed that stolons and rhizomes of bermudagrass have significant differences at the proteome level and light might play important regulatory roles in the discrepancy of the proteome profiles and specialization of the two stems, providing new insights into the adaptation of plant stems to aboveground and underground growth. BIOLOGICAL SIGNIFICANCE: As two types of specialized stems that grow underground and aboveground respectively, rhizomes and stolons play important roles in overwintering and ecological invasion of many perennial and clonal plants. However, because rhizomes and stolons rarely coexist in single plant species, the differences between the two stems remain unclear at the molecular level. In this study, through an iTRAQ comparative proteomic analysis, we reported the identification of 228 differentially accumulated protein species (DAPs) in rhizomes and stolons of bermudagrass for the first time. We found that the 228 DAPs were interconnected to form protein networks in regulating diverse cellular activities and biochemical reactions. We also observed that stolons growing underground showed similar physiological activities and DAP expression as those of underground-growing rhizomes, suggesting that light might play important regulatory roles in the specialization of stolons and rhizomes. These results expanded our understanding of the mysterious adaption of plant stems to different growth conditions.
狗牙根（Cynodon dactylon L.）作为一种重要的多年生暖季型草坪草种，能同时形成地下生长的根茎和地上生长的匍匐茎，使其成为一种繁殖迅速、再生能力强的克隆植物。在本研究中，我们利用iTRAQ技术比较了狗牙根品种阳江在同一发育阶段根茎和匍匐茎的节间蛋白质组。结果表明，有228种蛋白质在这两种特化茎中差异积累。与两种茎中淀粉、叶绿素、花青素和HO的含量差异一致，光合作用和类黄酮生物合成在匍匐茎中富含差异积累蛋白质（DAPs），而淀粉和蔗糖代谢、糖酵解以及HO代谢在根茎中富含DAPs。将匍匐茎埋于土壤中会导致叶绿素和花青素逐渐降解、淀粉积累以及HO增加，这与根茎的生理特征相似。这些结果共同表明，狗牙根的匍匐茎和根茎在蛋白质组水平上存在显著差异，光照可能在两种茎的蛋白质组谱差异和特化过程中发挥重要调节作用，为植物茎适应地上和地下生长提供了新的见解。生物学意义：根茎和匍匐茎分别作为两种在地下和地上生长的特化茎，在许多多年生和克隆植物的越冬和生态入侵中发挥着重要作用。然而，由于根茎和匍匐茎很少在单一植物物种中共存，二者在分子水平上的差异仍不明确。在本研究中，通过iTRAQ比较蛋白质组分析，我们首次报道了在狗牙根的根茎和匍匐茎中鉴定出228种差异积累蛋白质（DAPs）。我们发现这228种DAPs相互连接形成蛋白质网络，以调节多种细胞活动和生化反应。我们还观察到，地下生长的匍匐茎表现出与地下生长的根茎相似的生理活动和DAP表达，这表明光照可能在匍匐茎和根茎的特化过程中发挥重要调节作用。这些结果扩展了我们对植物茎对不同生长条件的神秘适应性的理解。
