The Key Laboratory of Plant Biotechnology of Liaoning Province, School of Life Science, Liaoning Normal University, No.1 Liushu South Street, Dalian, 650081, China.
State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Science, Sun Yat-Sen University, Guangzhou, 510275, China.
BMC Microbiol. 2021 May 12;21(1):143. doi: 10.1186/s12866-021-02206-1.
Seed dimorphism has been thought to be a bet-hedging strategy that helps plants survive in the disturbed environment and has been widely studied for its ecological adaptation mechanism. Many studies showed that seed-associated microorganisms play an important role in enhancing plant fitness, but information regarding endophytic bacteria associated with dimorphic seeds is limited. This study explores the influence of seed coat structure and seed phytochemical properties on the community composition and diversity of endophytic bacteria of dimorphic seeds of Suaeda glauca. In this study, we used 16S rRNA high-throughput gene sequencing method to compare the community composition and bacterial diversity between brown and black seeds of Suaeda glauca.
A significant difference was observed in seed coat structure and phytochemical properties between brown and black seeds of S. glauca. Total 9 phyla, 13 classes, 31 orders, 53 families, 102 genera were identified in the dimorphic seeds. The dominant phyla were Proteobacteria, Firmicutes, and Actinobacteria. The results showed that seed dimorphism had little impact on the diversity and richness of endophytic bacterial communities but significantly differs in the relative abundance of the bacterial community between brown and black seeds. At the phylum level, Actinobacteria tend to be enriched significantly in brown seeds. At the genus level, Rhodococcus, Ralstonia, Pelomonas and Bradyrhizobium tend to be enriched significantly in brown seeds, while Marinilactibacillus was mainly found in black seeds. Besides, brown seeds harbored a large number of bacteria with plant-growth-promoting traits, whereas black seeds presented bacteria with enzyme activities (i.e., pectinase, cellulolytic and xylanolytic activities).
The endophytic bacterial community compositions were significantly different between dimorphic seeds of Suaeda glauca, and play an important role in the ecological adaptation of dimorphic seeds by performing different biological function roles. The endophytic bacterial communities of the dimorphic seeds may be influenced mainly by the seed coat structureand partly by the seed phytochemical characteristics. These findings provide valuable information for better understanding of the ecological adaptation strategy of dimorphic seeds in the disturbed environment.
种子二型性被认为是一种避险策略，可以帮助植物在受干扰的环境中生存，并因其生态适应机制而得到广泛研究。许多研究表明，与种子相关的微生物在增强植物适应性方面发挥着重要作用，但有关与二型种子相关的内生细菌的信息有限。本研究探讨了种皮结构和种子次生代谢产物对盐地碱蓬二型种子内生细菌群落组成和多样性的影响。在本研究中，我们使用 16S rRNA 高通量基因测序方法比较了盐地碱蓬棕色和黑色种子内生细菌的群落组成和细菌多样性。
盐地碱蓬棕色和黑色种子在种皮结构和次生代谢产物方面存在显著差异。共鉴定出二型种子 9 个门、13 个纲、31 个目、53 个科、102 个属。优势门为变形菌门、厚壁菌门和放线菌门。结果表明，种子二型性对内生细菌群落的多样性和丰富度影响不大，但棕色和黑色种子之间的细菌群落相对丰度存在显著差异。在门水平上，放线菌在棕色种子中明显富集。在属水平上，棕色种子中罗尔斯通氏菌属、雷尔氏菌属、海单胞菌属和慢生根瘤菌属明显富集，而海洋芽孢杆菌属主要存在于黑色种子中。此外，棕色种子中含有大量具有植物生长促进特性的细菌，而黑色种子中则具有酶活性（即果胶酶、纤维素酶和木聚糖酶活性）的细菌。
盐地碱蓬二型种子的内生细菌群落组成存在显著差异，通过发挥不同的生物学功能作用，对二型种子的生态适应具有重要意义。二型种子的内生细菌群落主要受种皮结构影响，部分受种子次生代谢产物特性影响。这些发现为更好地理解二型种子在受干扰环境中的生态适应策略提供了有价值的信息。
