In photosynthetic eukaryotes,there are two well-characterized fructose-1,6-bisphosphatases(FBPases):the redox-insensitive cytosolic FBPase(cyFBPase),which participates in gluconeogenesis,and the redoxsensitive chlorop...In photosynthetic eukaryotes,there are two well-characterized fructose-1,6-bisphosphatases(FBPases):the redox-insensitive cytosolic FBPase(cyFBPase),which participates in gluconeogenesis,and the redoxsensitive chloroplastic FBPase(cpFBPasel),which is a critical enzyme in the Calvin cycle.Recent studies have identified a new chloroplastic FBPase,cpFBPase2;however,its phylogenetic distribution,evolutionary origin,and physiological function remain unclear.In this study,we identified and characterized these three FBPase isoforms in diverse,representative photosynthetic lineages and analyzed their phylogeny.In contrast to previous hypotheses,we found that cpFBPase2 is ubiquitous in photo synthetic eukaryotes.Additionally,all cpFBPase2 s from diverse lineages form a monophyly,suggesting cpFBPase2 is not a recently evolved enzyme restricted to land plants but rather evolved early in the evolution of photo synthetic organisms,and most likely,in the common ancestor of photosynthetic eukaryotes.cyFBPase was probably first duplicated to produce cpFBPase2,and then the latter duplicated to produce cpFBPase1.The ubiquitous coexistence of these two cpFBPases in chloroplasts is most likely the consequence of adaptation to different redox conditions of photosynthesis,especially those caused by recurrent changes in light conditions.展开更多
Elevated activities of cytosolic fructose-1,6-bisphosphatase(cyFBPase) and sedoheptulose-1,7-bisphosphatase(SBPase)are associated with higher yields in plants. In this study, the expression levels of the cyFBPase and ...Elevated activities of cytosolic fructose-1,6-bisphosphatase(cyFBPase) and sedoheptulose-1,7-bisphosphatase(SBPase)are associated with higher yields in plants. In this study, the expression levels of the cyFBPase and SBPase genes were increased by overexpressing rape(Brassica napus) cDNA in tobacco(Nicotiana tabacum) plants. The transgenic plants coexpressing cy FBPase and SBPase(TpFS), or expressing single cy FBPase(TpF) or SBPase(TpS) had 1.77-, 1.55-, 1.23-fold cyFBPase and 1.45-, 1.12-, 1.36-fold SBPase activities as compared to the wild-type(WT), respectively. Photosynthesis rates of TpF, TpS and TpFS increased 4, 20 and 25% compared with WT plants. The SBPase and cyFBPase positively regulated each other and functioned synergistically in transgenic tobacco plants. In addition, the sucrose contents of the three transgenic plants were higher than that of WT plants. The starch accumulation of the TpFS and TpS plants was improved by 53 and 37%, but slightly decreased in TpF plants. Moreover, the transgenic tobacco plants harbouring SBPase and/or cyFBPase genes showed improvements in their growth, biomass, dry weight, plant height, stem diameter, leaf size,flower number, and pod weight. In conclusion, co-expression of SBPase and cyFBPase may pave a new way for improving crop yield in agricultural applications.展开更多
基金the National Natural Science Foundation of China(31572256 and 31801967)State Key Laboratory of Genetic Resources and Evolution(GREKF17-03).
文摘In photosynthetic eukaryotes,there are two well-characterized fructose-1,6-bisphosphatases(FBPases):the redox-insensitive cytosolic FBPase(cyFBPase),which participates in gluconeogenesis,and the redoxsensitive chloroplastic FBPase(cpFBPasel),which is a critical enzyme in the Calvin cycle.Recent studies have identified a new chloroplastic FBPase,cpFBPase2;however,its phylogenetic distribution,evolutionary origin,and physiological function remain unclear.In this study,we identified and characterized these three FBPase isoforms in diverse,representative photosynthetic lineages and analyzed their phylogeny.In contrast to previous hypotheses,we found that cpFBPase2 is ubiquitous in photo synthetic eukaryotes.Additionally,all cpFBPase2 s from diverse lineages form a monophyly,suggesting cpFBPase2 is not a recently evolved enzyme restricted to land plants but rather evolved early in the evolution of photo synthetic organisms,and most likely,in the common ancestor of photosynthetic eukaryotes.cyFBPase was probably first duplicated to produce cpFBPase2,and then the latter duplicated to produce cpFBPase1.The ubiquitous coexistence of these two cpFBPases in chloroplasts is most likely the consequence of adaptation to different redox conditions of photosynthesis,especially those caused by recurrent changes in light conditions.
基金supported by the National Major Program on Transgenic Organisms from Ministry of Agriculture,China(2016ZX08005-004)。
文摘Elevated activities of cytosolic fructose-1,6-bisphosphatase(cyFBPase) and sedoheptulose-1,7-bisphosphatase(SBPase)are associated with higher yields in plants. In this study, the expression levels of the cyFBPase and SBPase genes were increased by overexpressing rape(Brassica napus) cDNA in tobacco(Nicotiana tabacum) plants. The transgenic plants coexpressing cy FBPase and SBPase(TpFS), or expressing single cy FBPase(TpF) or SBPase(TpS) had 1.77-, 1.55-, 1.23-fold cyFBPase and 1.45-, 1.12-, 1.36-fold SBPase activities as compared to the wild-type(WT), respectively. Photosynthesis rates of TpF, TpS and TpFS increased 4, 20 and 25% compared with WT plants. The SBPase and cyFBPase positively regulated each other and functioned synergistically in transgenic tobacco plants. In addition, the sucrose contents of the three transgenic plants were higher than that of WT plants. The starch accumulation of the TpFS and TpS plants was improved by 53 and 37%, but slightly decreased in TpF plants. Moreover, the transgenic tobacco plants harbouring SBPase and/or cyFBPase genes showed improvements in their growth, biomass, dry weight, plant height, stem diameter, leaf size,flower number, and pod weight. In conclusion, co-expression of SBPase and cyFBPase may pave a new way for improving crop yield in agricultural applications.
