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

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.

Adptatives Responses of the Species Ethmalosa fimbriata in Biétri Bay, a Highly Disturbed Environment

The growth and size at first sexual maturity of the species Ethmalosa fimbriata were studied in two sites in the Ebrié lagoon: Bietri, a highly anthropized environment and Vitré 2, a reference site. Growth parameters estimated from size frequencies showed that growth in both size and weight was faster in females than in males regardless of habitat. On the other hand, specimens from Biétri bay have a slower growth rate than those from Vitré 2. In Bietri bay, individuals are characterized by early sexual maturity. They reach sexual maturity at the age of 0.55 years (about 7 months), corresponding to a size of 6.13 cm for males and 8.42 cm for females; whereas in Vitré 2, they reach sexual maturity at the age of 0.82 years (about 10 months) corresponding to a size of 10.22 cm and 12.94 cm for males and females respectively. These results show that in a highly antropic environment, the growth of Ethmalosa fimbriata is affected and individuals reproduce earlier.

The Abundance of Odonata Insect in Lebak Swamp, Bukit Baru, Palembang, Indonesia

Lebak swamp in Bukit Baru has been largely degraded due to reclamation activity. Lebak swamp plays important role as land resource in Bukit Baru, Palembang. The aim of this study was to examine the composition of Odonata in lebak swamps in Bukit Baru, Palembang, Indonesia. The transect line (1 km) was used to collect odonata in the study area. This study recorded 8 species during the study period. The highest diversity of odonata was found in site A1. The highest abundance of odonata was recorded at site A2 and A4 and dominated by Ceriagrion coromandelianum and Orthetrum sabina. Neurothemis ramburii had the lowest abund ance at site A1 and A2, but absent at site A3 and A4. The occurrence of odonate species are lower at site around anthropogenic activity suggests the need to protect the lebak swamp so that such uncommon species will not go into local extinction. Neurothemis ramburii can become potential species to evaluate the rate of disturbed environment.

Insights into the Endophytic Bacterial Community Comparison and their Potential Role in the Dimorphic Seeds of Halophyte Suaeda Glauca

Background: The seed dimorphism was thought to be a bet-hedging strategy, which assists plants to survive in the disturbed environment and has been widely studied for their 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 the present study, we firstly used 16S rRNA high-throughput gene sequencing method to compare the bacterial diversity and community composition 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 bacterial function roles. The endophytic bacterial communities of the dimorphic seeds might be influenced mainly by the seed coat structure and partly by seed phytochemical characteristics. These findings provide valuable information for better understanding of the ecological adaptation strategy of dimorphic seeds in the disturbed environment.