Insights into the endophytic bacterial community comparison and their potential role in the dimorphic seeds of halophyte Suaeda glauca

Abstract

Background 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. Results 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). Conclusion 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.

Endorhizosphere of indigenous succulent halophytes: a valuable resource of plant growth promoting bacteria

“…There is a limited number of studies on the structure of endophytic communities associated with halophytes in different natural saline habitats. Only a few studies describe endophytic communities associated with Salicornia genus [ 18 ], especially Salicornia europaea [ 21 , 64 , 72 , 73 ], and even fewer describe the endophytic microbiota associated with representatives of Suaeda genus [ 71 , 75 ]. There are no reported data on endophyte microbiota communities associated with Suaeda maritima and Camphorosma genus in the current literature.…”

Dynamic changes in the endophytic bacterial community during maturation of Amorphophallus muelleri seeds

“…Endophytic bacteria in seeds are not only closely related to seed activity and seed quality but also affect various seed traits, such as seed germination, plant growth, disease occurrence, and stress resistance ( Walitang et al, 2017 ; Wang et al, 2021 ). In this study, high-throughput sequencing was used to reveal the composition and diversity of endophytic bacterial communities in A. muelleri .…”

“…Bradyrhizobium is a group of slow-growing, alkali-producing, nitrogen-fixing rhizobia. Some Bradyrhizobium strains can fix nitrogen and can promote the growth and root development of some plants ( Wang et al, 2021 ). In this study, with the increase in maturity stage, the relative abundance of Bradyrhizobium in the seed coat showed a gradually increasing trend.…”

“…The seed coat is the “armor” of the seed, so the significant increase in the relative abundance of Streptomyces is conducive to increasing the resistance of the mature seed coat and protecting the seed from the invasion of plant pathogens. Endophytic bacteria can improve plant adaptability by enhancing nutrient mobilization, nitrogen fixation, and phosphate solubilization and conferring plant resistance to pathogens ( Hardoim et al, 2012 ; Wang et al, 2021 ). Therefore, we speculate that fully mature seeds and seed coats contain many microorganisms with plant growth-promoting traits and contribute to plant resistance, which may contribute to the establishment and development of seedlings of A. muelleri .…”

“…To avoid bacterial contamination of the environment, surface sterilization of collected seeds was performed according to Wang et al (2021) with some improvements. First, the seeds were rinsed with 50 mL of sterilized distilled water at least three times or until no turbidity was observed.…”