Diversity of culturable alginate lyase-excreting bacteria associated with Sargassum

Large numbers of bacteria live on the surface of various brown algae and can produce alginate lyases to consume alginate,an important component of the cell wall of brown algae.Sargassum is a genus of the largest canopyforming brown algae of more than 150 species,which are widely distributed in tropical and subtropical environments.However,our knowledge about the epiphytic bacteria and the alginate lyase-excreting bacteria from Sargassum is still primitive.Here,we investigated the diversity of the culturable epiphytic bacteria and alginate-degrading bacteria from Sargassum samples collected from the coastal seawaters of Shandong Province,China.In total,37 strains belonging to 21 genera in 3 phyla were isolated,including 15 previously unreported genera,of which Vibrio(6/37)and Pseudoalteromonas(5/37)are the dominant genera.Eight strains,mainly Vibrio and Pseudoalteromonas species,were further identified as alginate lyase-excreting strains that can utilize alginate for growth.The extracellular alginolytic activity of the 8 strains was determined,and strains Vibrio sp.C42and Pseudoalteromonas sp.M9 showed the highest activity.These results provide a better understanding of brown algae epiphytes and alginate-degrading bacteria,and are fundamental for further studies on the interactions between brown algae and their epiphytes.

Function of the auxin-responsive gene TaSAUR75 under salt and drought stress

Small auxin-upregulated RNAs(SAURs) are genes regulated by auxin and environmental factors. In this study, we identified a SAUR gene in wheat, Ta SAUR75. Under salt stress,Ta SAUR75 is downregulated in wheat roots. Subcellular localization revealed that Ta SAUR75 was localized in both the cytoplasm and nucleus. Overexpression of Ta SAUR75 increased drought and salt tolerance in Arabidopsis. Transgenic lines showed higher root length and survival rate and higher expression of some stress-responsive genes than control plants under salt and drought stress. Less H_2O_2 accumulated in transgenic lines than in control plants under drought stress. Our findings reveal a positive regulatory role of the auxin-responsive gene Ta SAUR75 in plant responses to drought and salt stress and provide a candidate gene for improvement of abiotic stress tolerance in crop breeding.

Investigation and Analysis of Crop Germplasm Resources in Coastal Areas of Shandong Province

This study focused on the investigation of crop germplasm resources in coastal areas of Shandong Province, including132 villages in 82 towns of 34 counties. The survey collected local varieties and wild resources of grain crops, economic crops,vegetables and fruit trees, and a total of 848 samples were collected, belonging to 54 species of 39 genera in 15 families. In this study, the current situation and growth and decline conditions of crop germplasm resources were investigated, and their botanical classification and utilization importance were analyzed. Furthermore, the conservation, development and utilization of crop germplasm resources in coastal areas of Shandong Province were also discussed in this paper.