盐胁迫对长穗偃麦草根系分泌碳水化合物的影响OA

INTRODUCTION:The carbohydrates secreted by plant roots play a crucial role in modulating the carbon source supply and metabolic activity of soil microorganisms. RATIONALE:In order to unveil the response mechanism of root-secreted carbohydrates in salt-tolerant plants to the intensity of salt stress,this study focused on the salt-tolerant forage grass Thinopyrum ponticum.Four levels of salt stress intensity were conducted by adding NaCl,including control,light,moderate,and heavy stress conditions(with soil salt contents of 0％,0.2％,0.4％,and 0.6％,respectively).Untargeted metabolomics techniques were employed to analyze the compositional alterations of root-secreted carbohydrates and their correlations with the rhizosphere soil properties were evaluated. RESULTS:The results demonstrated that:(1)Compared to the control,salt stress significantly decreased the contents of five types of carbohydrates,namely glycoside,aminoglycoside,D-glucosamine,2-O-methyl-L-fucose and galactoside,while markedly increasing glucose content;(2)Glycosides were the predominant carbohydrates secreted by T.ponticum roots,accounting for(79.63±8.19)％of the total relative abundance,whereas the remaining five carbohydrate types ranged from(3.40±0.53)％to(4.57±1.61)％;(3)Root-secreted carbohydrates exhibited significant differences between the control and light,moderate,or heavy salt stress treatments,but no significant distinctions were observed among the latter three treat-ments;(4)Soil electrical conductivity and nitrate nitrogen content were identified as key factors responsible for the down-regulation of the five carbohydrate types,while soil pH was the primary factor driving the up-regulation of glucose. CONCLUSION:T.ponticum can adapt to salt-stressed environments by regulating the content of carbohydrates secreted by its roots.Meanwhile,the abundance of carbohydrates secreted by the roots is also influenced by the soil properties.