Cytokinins are mobile phytohormones that regulate plant growth,development,and environmental adaptability.The major cytokinin species include isopentenyl adenine(iP),trans-zeatin(tZ),cis-zeatin(cZ),and dihydrozeatin(D...Cytokinins are mobile phytohormones that regulate plant growth,development,and environmental adaptability.The major cytokinin species include isopentenyl adenine(iP),trans-zeatin(tZ),cis-zeatin(cZ),and dihydrozeatin(DZ).The spatial distributions of different cytokinin species in different organelles,cells,tissues,and organs are primarily shaped by biosynthesis via isopentenyltransferases(IPT),cytochrome P450 monooxygenase,and 50-ribonucleotide phosphohydrolase and by conjugation or catabolism via glycosyltransferase or cytokinin oxidase/dehydrogenase.Cytokinins bind to histidine receptor kinases in the endoplasmic reticulum or plasma membrane and relay signals to response regulators in the nucleus via shuttle proteins known as histidine phosphotransfer proteins.The movements of cytokinins from sites of biosynthesis to sites of signal perception usually require long-distance,intercellular,and intracellular transport.In the past decade,ATP-binding cassette(ABC)transporters,purine permeases(PUP),AZA-GUANINE RESISTANT(AZG)transporters,equilibrative nucleoside transporters(ENT),and Sugars Will Eventually Be Exported transporters(SWEET)have been characterized as involved in cytokinin transport processes.This review begins by introducing the spatial distributions of various cytokinins and the subcellular localizations of the proteins involved in their metabolism and signaling.Highlights focus on an inventory of the characterized transporters involved in cytokinin compartmentalization,including long-distance,intercellular,and intracellular transport,and the regulation of the spatial distributions of cytokinins by environmental cues.Future directions for cytokinin research are also discussed.展开更多
基金supported by the National Natural Science Foundation of China(32370334,32100270 to J.Z.31470370 to K.Z.)the Zhejiang Provincial Natural Science Foundation of China(grants LZ23C020001 to K.Z.and LY22C020003 to J.Z.).
文摘Cytokinins are mobile phytohormones that regulate plant growth,development,and environmental adaptability.The major cytokinin species include isopentenyl adenine(iP),trans-zeatin(tZ),cis-zeatin(cZ),and dihydrozeatin(DZ).The spatial distributions of different cytokinin species in different organelles,cells,tissues,and organs are primarily shaped by biosynthesis via isopentenyltransferases(IPT),cytochrome P450 monooxygenase,and 50-ribonucleotide phosphohydrolase and by conjugation or catabolism via glycosyltransferase or cytokinin oxidase/dehydrogenase.Cytokinins bind to histidine receptor kinases in the endoplasmic reticulum or plasma membrane and relay signals to response regulators in the nucleus via shuttle proteins known as histidine phosphotransfer proteins.The movements of cytokinins from sites of biosynthesis to sites of signal perception usually require long-distance,intercellular,and intracellular transport.In the past decade,ATP-binding cassette(ABC)transporters,purine permeases(PUP),AZA-GUANINE RESISTANT(AZG)transporters,equilibrative nucleoside transporters(ENT),and Sugars Will Eventually Be Exported transporters(SWEET)have been characterized as involved in cytokinin transport processes.This review begins by introducing the spatial distributions of various cytokinins and the subcellular localizations of the proteins involved in their metabolism and signaling.Highlights focus on an inventory of the characterized transporters involved in cytokinin compartmentalization,including long-distance,intercellular,and intracellular transport,and the regulation of the spatial distributions of cytokinins by environmental cues.Future directions for cytokinin research are also discussed.
