The miniature1 （mn1） seed phenotype is a loss-of-function mutation at the Mnl locus that encodes a cell wall invertase; its deficiency leads to pleiotropic changes including altered sugar levels and decreased levels...The miniature1 （mn1） seed phenotype is a loss-of-function mutation at the Mnl locus that encodes a cell wall invertase; its deficiency leads to pleiotropic changes including altered sugar levels and decreased levels of IAA throughout seed development. To understand the molecular details of such a sugar-hormone relationship, we have initiated studies on IAA biosynthesis genes in developing seeds of maize. Two tryptophan-dependent pathways of IAA biosynthesis, tryptamine （TAM） and indole-3-pyruvic acid （IPA）, are of particular interest. We report on molecular isolation and characterization of an endosperm-specific ZmTARelatedl （ZmTarl） gene of the IPA branch; we have also reported recently on ZmYucl gene in the TAM branch. Comparative gene expression analyses here have shown that （1） the ZmTarl transcripts were approximately 10-fold higher levels than the ZmYucl; （2） although both genes showed the highest level of expression at 8-12 d after pollination （DAP） coincident with an early peak in IAA levels, the two showed highly divergent （antagonistic） response at 12 and 16 DAP but similar patterns at 20 and 28 DAP in the Mnl and ran1 endosperm. The Western blot analyses for the ZmTAR1 protein, however, displayed disconcordant protein/transcript expression patterns. Overall, these data report novel observations on redundant trp-dependent pathways of auxin biosynthesis in developing seeds of maize, and suggest that homeostatic control of IAA in this important sink is highly complex and may be regulated by both sucrose metabolism and developmental signals.展开更多
Grain filling is a crucial process that affects yield in rice(Oryza sativa L.).Auxin biosynthesis and signaling are closely related to rice yield;therefore,it is important to understand the effects of auxin biosynthes...Grain filling is a crucial process that affects yield in rice(Oryza sativa L.).Auxin biosynthesis and signaling are closely related to rice yield;therefore,it is important to understand the effects of auxin biosynthesis on rice grain filling to improve crop yield.In this study,we used physiological and molecular strategies to identify the roles of auxin in rice grain filling.Exogenous application of auxin(IAA)or auxin analogues(2,4-D)to young spikelets and flag leaves improved the seed-setting rate and yield per spike.Furthermore,real-time quantitative PCR assays confirmed that nine members of the OsYUCCA family of auxin biosynthetic genes were upregulated during grain filling,implication that auxin biosynthesis plays a major role in grain development.The specific expression of either Arabidopsis AtYUCCA1 or OsYUCCA2 in the endosperm or leaves resulted in increased expression of OsIAA genes and auxin content of seeds,as well as increased grain filling and seed-setting rate.This result establishes that the auxin content in grains and leaves is important for grain development.Our findings further highlight the potential applications for improving rice yield by elevating targeted gene expression in specific tissues.展开更多
The influence of nitric acid （HNO3） as a strong mineral acid on rooting response of fresh mad aging mung bean cuttings has been studied on the level of Indole-3-Acetic Acid （IAA）. The data revealed significant inc...The influence of nitric acid （HNO3） as a strong mineral acid on rooting response of fresh mad aging mung bean cuttings has been studied on the level of Indole-3-Acetic Acid （IAA）. The data revealed significant increase in rooting response of fresh cuttings treated with （0.0001% and 0.1%） concentrations of HNO3 solution, significant increase in rooting response of aged cuttings （for 3 days in d/H20） with （0.0001% and 0.01%） concentration of HNO3 solution and highly significant increase in rooting response of aged cuttings （for 3 days in HNO3 solution） with （0.0001%） concentration, while highly concentration （0.5%） revealed highly significant decrease in rooting response compared to control （d/H20）. Quantitative estimation oflAA by spectrophotometric method as indicators for oxidative processes that occurrence during aging phenomenon verified a highly significant increase of IAA content in hypocotyles of fresh and aged cuttings in optimal concentration of HNO3.展开更多
文摘The miniature1 （mn1） seed phenotype is a loss-of-function mutation at the Mnl locus that encodes a cell wall invertase; its deficiency leads to pleiotropic changes including altered sugar levels and decreased levels of IAA throughout seed development. To understand the molecular details of such a sugar-hormone relationship, we have initiated studies on IAA biosynthesis genes in developing seeds of maize. Two tryptophan-dependent pathways of IAA biosynthesis, tryptamine （TAM） and indole-3-pyruvic acid （IPA）, are of particular interest. We report on molecular isolation and characterization of an endosperm-specific ZmTARelatedl （ZmTarl） gene of the IPA branch; we have also reported recently on ZmYucl gene in the TAM branch. Comparative gene expression analyses here have shown that （1） the ZmTarl transcripts were approximately 10-fold higher levels than the ZmYucl; （2） although both genes showed the highest level of expression at 8-12 d after pollination （DAP） coincident with an early peak in IAA levels, the two showed highly divergent （antagonistic） response at 12 and 16 DAP but similar patterns at 20 and 28 DAP in the Mnl and ran1 endosperm. The Western blot analyses for the ZmTAR1 protein, however, displayed disconcordant protein/transcript expression patterns. Overall, these data report novel observations on redundant trp-dependent pathways of auxin biosynthesis in developing seeds of maize, and suggest that homeostatic control of IAA in this important sink is highly complex and may be regulated by both sucrose metabolism and developmental signals.
基金supported by the National Natural Science Foundation of China(Grant Nos.31801193,31820103008,91754104,and 31670283)the Fundamental Research Funds for the Central Universities(No.lzujbky-2020-it13).
文摘Grain filling is a crucial process that affects yield in rice(Oryza sativa L.).Auxin biosynthesis and signaling are closely related to rice yield;therefore,it is important to understand the effects of auxin biosynthesis on rice grain filling to improve crop yield.In this study,we used physiological and molecular strategies to identify the roles of auxin in rice grain filling.Exogenous application of auxin(IAA)or auxin analogues(2,4-D)to young spikelets and flag leaves improved the seed-setting rate and yield per spike.Furthermore,real-time quantitative PCR assays confirmed that nine members of the OsYUCCA family of auxin biosynthetic genes were upregulated during grain filling,implication that auxin biosynthesis plays a major role in grain development.The specific expression of either Arabidopsis AtYUCCA1 or OsYUCCA2 in the endosperm or leaves resulted in increased expression of OsIAA genes and auxin content of seeds,as well as increased grain filling and seed-setting rate.This result establishes that the auxin content in grains and leaves is important for grain development.Our findings further highlight the potential applications for improving rice yield by elevating targeted gene expression in specific tissues.
文摘The influence of nitric acid （HNO3） as a strong mineral acid on rooting response of fresh mad aging mung bean cuttings has been studied on the level of Indole-3-Acetic Acid （IAA）. The data revealed significant increase in rooting response of fresh cuttings treated with （0.0001% and 0.1%） concentrations of HNO3 solution, significant increase in rooting response of aged cuttings （for 3 days in d/H20） with （0.0001% and 0.01%） concentration of HNO3 solution and highly significant increase in rooting response of aged cuttings （for 3 days in HNO3 solution） with （0.0001%） concentration, while highly concentration （0.5%） revealed highly significant decrease in rooting response compared to control （d/H20）. Quantitative estimation oflAA by spectrophotometric method as indicators for oxidative processes that occurrence during aging phenomenon verified a highly significant increase of IAA content in hypocotyles of fresh and aged cuttings in optimal concentration of HNO3.
