Selenium-enriched tea is highly valued for its nutritional and health benefits due to its rich selenium content and various bioactive compounds,such as tea polyphenols,theanine,and catechins.However,the limited availa...Selenium-enriched tea is highly valued for its nutritional and health benefits due to its rich selenium content and various bioactive compounds,such as tea polyphenols,theanine,and catechins.However,the limited availability of selenium resources in soil significantly impedes the development of the seleniumenriched tea industry.Selenium-reducing bacteria,as functional microorganisms capable of efficiently converting inorganic selenium into selenium nanoparticles(SeNPs),play a crucial role in selenium enrichment and stabilization processes in tea plants.In this study,a highly selenium-tolerant strain,Raoultella ornithinolytica S-1,was successfully isolated,demonstrating an exceptional tolerance to sodium selenite concentrations of up to 200 mM.This strain not only efficiently reduces sodium selenite to SeNPs,but also exhibits multiple growth-promoting functions,including nitrogen fixation,phosphorus solubilization,siderophore production,and IAA synthesis.Furthermore,the S-1 bio-nano selenium microbial agent was successfully prepared using mannitol as the carbon source,tryptone as the nitrogen source,and calcium chloride as the inorganic salt at 5 mM sodium selenite and 4%inoculum.Foliar spraying of the microbial agent significantly increased selenium content in the summer-autumn tea fresh leaves,enhancing the levels of refreshing taste compounds,such as soluble sugars,theanine,and other free amino acids.Concurrently,it reduced the content of bitter substances(tea polyphenols and catechins)and harmful elements(aluminium,cadmium,and fluorine),thereby improving the quality and safety of the summer-autumn tea.This study expands the application of selenium-enriched microorganisms and provides an innovative solution for the development of selenium-enriched tea.展开更多
[Objectives] This study was carried out to explore the selenium-enriching effect of different crops, and provide certain references for production of selenium-enriched agricultural products. [Methods] Four kinds of cr...[Objectives] This study was carried out to explore the selenium-enriching effect of different crops, and provide certain references for production of selenium-enriched agricultural products. [Methods] Four kinds of crops (tomato, leaf mustard, peanut, and carrot) were exogenous selenium fertilizer treated, to explore the selenium-enriching effects on these crops. [Results] Exogenous application of microbial nano-selenium can significantly increase the selenium content of the crops, of which the effects on big tomato (Weiyanuo) were the best. After spraying, the selenium content increased by 1.39 times, and at the same time the sugar content of tomato was also increased. [Conclusions] This study is expected to provide references for increase of the selenium content of agricultural products.展开更多
基金supported by the research and developmentprogram of China Se-enriched industry research institute(Grant No.2024FXZX-01)the Key Research and Development Program ofShaanxi(Grant No.2024NC-ZDCYL-04-07 and 2025NC-YBXM-240)the China Agricul-tural Research System of the Ministry of Finance and the Ministry ofAgriculture and Rural Affairs(CARS-19).
摘要Selenium-enriched tea is highly valued for its nutritional and health benefits due to its rich selenium content and various bioactive compounds,such as tea polyphenols,theanine,and catechins.However,the limited availability of selenium resources in soil significantly impedes the development of the seleniumenriched tea industry.Selenium-reducing bacteria,as functional microorganisms capable of efficiently converting inorganic selenium into selenium nanoparticles(SeNPs),play a crucial role in selenium enrichment and stabilization processes in tea plants.In this study,a highly selenium-tolerant strain,Raoultella ornithinolytica S-1,was successfully isolated,demonstrating an exceptional tolerance to sodium selenite concentrations of up to 200 mM.This strain not only efficiently reduces sodium selenite to SeNPs,but also exhibits multiple growth-promoting functions,including nitrogen fixation,phosphorus solubilization,siderophore production,and IAA synthesis.Furthermore,the S-1 bio-nano selenium microbial agent was successfully prepared using mannitol as the carbon source,tryptone as the nitrogen source,and calcium chloride as the inorganic salt at 5 mM sodium selenite and 4%inoculum.Foliar spraying of the microbial agent significantly increased selenium content in the summer-autumn tea fresh leaves,enhancing the levels of refreshing taste compounds,such as soluble sugars,theanine,and other free amino acids.Concurrently,it reduced the content of bitter substances(tea polyphenols and catechins)and harmful elements(aluminium,cadmium,and fluorine),thereby improving the quality and safety of the summer-autumn tea.This study expands the application of selenium-enriched microorganisms and provides an innovative solution for the development of selenium-enriched tea.
基金Supported by Program of Local Specialty Crop Varieties and Protective Cultivation Technique in Foshan City(Agricultural Technology Extension Project of Foshan City in 2017-2018)Characteristic Vegetable Innovation Team of Modern Agricultural Industrial Technology System of Guangdong Province(2016LM1015)
摘要[Objectives] This study was carried out to explore the selenium-enriching effect of different crops, and provide certain references for production of selenium-enriched agricultural products. [Methods] Four kinds of crops (tomato, leaf mustard, peanut, and carrot) were exogenous selenium fertilizer treated, to explore the selenium-enriching effects on these crops. [Results] Exogenous application of microbial nano-selenium can significantly increase the selenium content of the crops, of which the effects on big tomato (Weiyanuo) were the best. After spraying, the selenium content increased by 1.39 times, and at the same time the sugar content of tomato was also increased. [Conclusions] This study is expected to provide references for increase of the selenium content of agricultural products.