Pectin contributes greatly to cell wall phosphorus(P)remobilization.However,it is currently unclear whether the methylesterification degree of the pectin,which is related to the activity of pectin methylesterases(PMEs...Pectin contributes greatly to cell wall phosphorus(P)remobilization.However,it is currently unclear whether the methylesterification degree of the pectin,which is related to the activity of pectin methylesterases(PMEs),is also involved in this process.Here,we demonstrated that elevated PME activity can facilitate the remobilization of P deposited in the cell wall.P-deficient conditions resulted in the reduction of root cell wall P content.This reduction was more pronounced in Nipponbare than in Kasalath,in company with a significant increment of the PME activity,indicating a possible relationship between elevated PME activity and cell wall P remobilization.This hypothesis was supported by in vitro experiments,as pectin with lower methylesterification degree had higher ability to release inorganic P(Pi)from insoluble FePO_(4).Furthermore,among the 35 OsPME members in rice,only the expression of OsPME14 showed a relationship with PME activity.In addition,transgenic rice lines overexpressing OsPME14 had increased PME activity,released more P from the root cell wall,and more resistant to P deficiency.In conclusion,PMEs enhance P remobilization in P-starved rice by increasing PME activity in Nipponbare,which in turn helps to remobilize P from the cell wall,and thus makes more available P.展开更多
Tomato processing includes a break step, which involves rapid heating of freshly chopped tomatoes to >90°C for hot break, or 60°C to 77°C for cold break. Pectolytic enzyme deactivation is...Tomato processing includes a break step, which involves rapid heating of freshly chopped tomatoes to >90°C for hot break, or 60°C to 77°C for cold break. Pectolytic enzyme deactivation is believed to be the key element in the hot break step;therefore, pectin content of different products should be qualitatively distinct. The objective of this study was to investigate the effect of hot break versus cold break on the cell-wall pectin of tomato. Cell-wall pectin from hot and cold break tomato products was isolated and analyzed for carbohydrate composition, degree of polymerization, and degree of esterification. The results showed no observable differences in the cell-wall pectin isolated from the two products, indicating that there was no significant pectolytic breakdown of the tomato in the cold break product, and the pectin might not, by itself, contribute to the differences in the final product viscosity resulting from the two processing techniques.展开更多
基金This study was supported by the Foundation for Distinguished Young Scholars of Jiangsu Province,China(Grant No.BK20190050)Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2015250)+2 种基金the‘Strategic Priority Research Program’of the Chinese Academy of Sciences(Grant No.XDB15030300)National Science Foundation of China(Grant No.31501825)the State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources in China in 2020(Grant No.SKLCUSA-b201909).
文摘Pectin contributes greatly to cell wall phosphorus(P)remobilization.However,it is currently unclear whether the methylesterification degree of the pectin,which is related to the activity of pectin methylesterases(PMEs),is also involved in this process.Here,we demonstrated that elevated PME activity can facilitate the remobilization of P deposited in the cell wall.P-deficient conditions resulted in the reduction of root cell wall P content.This reduction was more pronounced in Nipponbare than in Kasalath,in company with a significant increment of the PME activity,indicating a possible relationship between elevated PME activity and cell wall P remobilization.This hypothesis was supported by in vitro experiments,as pectin with lower methylesterification degree had higher ability to release inorganic P(Pi)from insoluble FePO_(4).Furthermore,among the 35 OsPME members in rice,only the expression of OsPME14 showed a relationship with PME activity.In addition,transgenic rice lines overexpressing OsPME14 had increased PME activity,released more P from the root cell wall,and more resistant to P deficiency.In conclusion,PMEs enhance P remobilization in P-starved rice by increasing PME activity in Nipponbare,which in turn helps to remobilize P from the cell wall,and thus makes more available P.
文摘Tomato processing includes a break step, which involves rapid heating of freshly chopped tomatoes to >90°C for hot break, or 60°C to 77°C for cold break. Pectolytic enzyme deactivation is believed to be the key element in the hot break step;therefore, pectin content of different products should be qualitatively distinct. The objective of this study was to investigate the effect of hot break versus cold break on the cell-wall pectin of tomato. Cell-wall pectin from hot and cold break tomato products was isolated and analyzed for carbohydrate composition, degree of polymerization, and degree of esterification. The results showed no observable differences in the cell-wall pectin isolated from the two products, indicating that there was no significant pectolytic breakdown of the tomato in the cold break product, and the pectin might not, by itself, contribute to the differences in the final product viscosity resulting from the two processing techniques.
