Abstract: Cell death is a common event in all types of plant organisms. Understanding the phenomenon of programmed cell death (PCD) is an important area of research for plant scientists because of its role in senescen...Abstract: Cell death is a common event in all types of plant organisms. Understanding the phenomenon of programmed cell death (PCD) is an important area of research for plant scientists because of its role in senescence and the post-harvest quality of ornamentals, fruits, and vegetables. In the present paper, PCD in relation to petal senescence in ornamental plants is reviewed. Morphological, anatomical, physiological, and biochemical changes that are related to PCD in petals, such as water content, sink-source relationships, hormones, genes, and signal transduction pathways, are discussed. Several approaches to improving the quality of post-harvest ornamentals are reviewed and some prospects for future research are given.展开更多
Petals and leaves share common evolutionary origins but have different phenotypic characteristics,such as the absence of stomata in the petals of most angiosperm species.Plant NAC transcription factor,NAP,is involved ...Petals and leaves share common evolutionary origins but have different phenotypic characteristics,such as the absence of stomata in the petals of most angiosperm species.Plant NAC transcription factor,NAP,is involved in ABA responses and regulates senescence-associated genes,and especially those that affect stomatal movement.However,the regulatory mechanisms and significance of NAP action in senescing astomatous petals is unclear.A major limiting factor is failure of flower opening and accelerated senescence.Our goal is to understand the finely regulatory mechanism of dehydration tolerance and aging in rose flowers.We functionally characterized RhNAP,an AtNAP-like transcription factor gene that is induced by dehydration and aging in astomatous rose petals.Cytokinins(CKs)are known to delay petal senescence and we found that a cytokinin oxidase/dehydrogenase gene 6(RhCKX6)shares similar expression patterns with RhNAP.Silencing of RhNAP or RhCKX6 expression in rose petals by virus induced gene silencing markedly reduced petal dehydration tolerance and delayed petal senescence.Endogenous CK levels in RhNAP-or RhCKX6-silenced petals were significantly higher than those of the control.Moreover,RhCKX6 expression was reduced in RhNAP-silenced petals.This suggests that the expression of RhCKX6 is regulated by RhNAP.Yeast one-hybrid experiments and electrophoresis mobility shift assays showed that RhNAP binds to the RhCKX6 promoter in heterologous in vivo system and in vitro,respectively.Furthermore,the expression of putative signal transduction and downstream genes of ABA-signaling pathways were also reduced due to the repression of PP2C homolog genes by RhNAP in rose petals.Taken together,our study indicates that the RhNAP/RhCKX6 interaction represents a regulatory step enhancing dehydration tolerance in young rose petals and accelerating senescence in mature petals in a stomata-independent manner.展开更多
Flowers are key organs in many ornamental plants,and various phases of flower development impact their economic value.The final stage of petal development is associated with flower senescence,which is an irreversible ...Flowers are key organs in many ornamental plants,and various phases of flower development impact their economic value.The final stage of petal development is associated with flower senescence,which is an irreversible process involving programmed cell death,and premature senescence of cut flowers often results in major losses in quality during postharvest handling.Flower opening and senescence are two sequential processes.As flowers open,the stamens are exposed to attract pollinators.Once pollination occurs,flower senescence is initiated.Both the opening and senescence processes are regulated by a range of endogenous phytohormones and environmental factors.Ethylene acts as a central regulator for the ethylene-sensitive flowers.Other phytohormones,including auxin,gibberellin,cytokinin,jasmonic acid and abscisic acid,are also involved in the control of petal expansion and senescence.Water status also directly influences postharvest flower opening,while pollination is a key event in initiating the onset flower senescence.Here,we review the current understanding of flower opening and senescence,and propose future research directions,such as the study of interactions between hormonal and environmental signals,the application of new technology,and interdisciplinary research.展开更多
文摘Abstract: Cell death is a common event in all types of plant organisms. Understanding the phenomenon of programmed cell death (PCD) is an important area of research for plant scientists because of its role in senescence and the post-harvest quality of ornamentals, fruits, and vegetables. In the present paper, PCD in relation to petal senescence in ornamental plants is reviewed. Morphological, anatomical, physiological, and biochemical changes that are related to PCD in petals, such as water content, sink-source relationships, hormones, genes, and signal transduction pathways, are discussed. Several approaches to improving the quality of post-harvest ornamentals are reviewed and some prospects for future research are given.
基金This work was supported by the National Key R&D Program of China(2019YFD1000404)the Construction of Beijing Science and Technology Innovation and Service Capacity in Top Subjects(CEFFPXM2019_014207_000032).
文摘Petals and leaves share common evolutionary origins but have different phenotypic characteristics,such as the absence of stomata in the petals of most angiosperm species.Plant NAC transcription factor,NAP,is involved in ABA responses and regulates senescence-associated genes,and especially those that affect stomatal movement.However,the regulatory mechanisms and significance of NAP action in senescing astomatous petals is unclear.A major limiting factor is failure of flower opening and accelerated senescence.Our goal is to understand the finely regulatory mechanism of dehydration tolerance and aging in rose flowers.We functionally characterized RhNAP,an AtNAP-like transcription factor gene that is induced by dehydration and aging in astomatous rose petals.Cytokinins(CKs)are known to delay petal senescence and we found that a cytokinin oxidase/dehydrogenase gene 6(RhCKX6)shares similar expression patterns with RhNAP.Silencing of RhNAP or RhCKX6 expression in rose petals by virus induced gene silencing markedly reduced petal dehydration tolerance and delayed petal senescence.Endogenous CK levels in RhNAP-or RhCKX6-silenced petals were significantly higher than those of the control.Moreover,RhCKX6 expression was reduced in RhNAP-silenced petals.This suggests that the expression of RhCKX6 is regulated by RhNAP.Yeast one-hybrid experiments and electrophoresis mobility shift assays showed that RhNAP binds to the RhCKX6 promoter in heterologous in vivo system and in vitro,respectively.Furthermore,the expression of putative signal transduction and downstream genes of ABA-signaling pathways were also reduced due to the repression of PP2C homolog genes by RhNAP in rose petals.Taken together,our study indicates that the RhNAP/RhCKX6 interaction represents a regulatory step enhancing dehydration tolerance in young rose petals and accelerating senescence in mature petals in a stomata-independent manner.
基金This work was supported by the National Natural Science Foundation of China(Grant No.31730079,31902059)Science and Technology Program of Yunnan Province(Grant No.202102AE090001).
文摘Flowers are key organs in many ornamental plants,and various phases of flower development impact their economic value.The final stage of petal development is associated with flower senescence,which is an irreversible process involving programmed cell death,and premature senescence of cut flowers often results in major losses in quality during postharvest handling.Flower opening and senescence are two sequential processes.As flowers open,the stamens are exposed to attract pollinators.Once pollination occurs,flower senescence is initiated.Both the opening and senescence processes are regulated by a range of endogenous phytohormones and environmental factors.Ethylene acts as a central regulator for the ethylene-sensitive flowers.Other phytohormones,including auxin,gibberellin,cytokinin,jasmonic acid and abscisic acid,are also involved in the control of petal expansion and senescence.Water status also directly influences postharvest flower opening,while pollination is a key event in initiating the onset flower senescence.Here,we review the current understanding of flower opening and senescence,and propose future research directions,such as the study of interactions between hormonal and environmental signals,the application of new technology,and interdisciplinary research.
