查看更多>>摘要：Thermomorphogenesis and the heat shock(HS)response are distinct thermal responses in plants that are regulated by PHYTOCHROME-INTERAC-TING FACTOR 4(PIF4)and HEAT SHOCK FACTOR A1s(HSFA1s),respectively.Little is known about whether these responses are interconnected and whether they are activated by similar mechanisms.An analysis of transcriptome dynamics in re-sponse to warm temperature(28℃)treatment re-vealed that 30 min of exposure activated the expression of a subset of HSFA1 target genes in Arabidopsis thaliana.Meanwhile,a loss-of-function HSFA1 quadruple mutant(hsfa1-cq)was insensitive to warm temperature-induced hypo-cotyl growth.In hsfa1-cq plants grown at 28℃,the protein and transcript levels of PIF4 were greatly reduced,and the circadian rhythm of many thermomorphogenesis-related genes(including PIF4)was disturbed.Additionally,the nuclear localization of HSFA1s and the binding of HSFA1d to the PIF4 promoter increased following warm temperature exposure,whereas PIF4 overexp-ression in hsfa1-cq partially rescued the altered warm temperature-induced hypocotyl growth of the mutant.Taken together,these results suggest that HSFA1s are required for PIF4 accumulation at a warm temperature,and they establish a central role for HSFA1s in regulating both thermomorpho-genesis and HS responses in Arabidopsis.
查看更多>>摘要：Dormancy is an adaptive trait which prevents seeds from germinating under unfavorable envi-ronmental conditions.Seeds with weak dormancy undergo pre-harvest sprouting(PHS)which de-creases grain yield and quality.Understanding the genetic mechanisms that regulate seed dormancy and resistance to PHS is crucial for ensuring global food security.In this study,we illustrated the function and molecular mechanism of TaSRO1 in the regulation of seed dormancy and PHS resist-ance by suppressing TaVP1.The tasro1 mutants exhibited strong seed dormancy and enhanced resistance to PHS,whereas the mutants of tavp1 displayed weak dormancy.Genetic evidence has shown that TaVP1 is epistatic to TaSRO1.Bio-chemical evidence has shown that TaSRO1 inter-acts with TaVP1 and represses the transcriptional activation of the PHS resistance genes TaPHS1 and TaSdr.Furthermore,TaSRO1 undermines the synergistic activation of TaVP1 and TaABI5 in PHS resistance genes.Finally,we highlight the great potential of tasro1 alleles for breeding elite wheat cultivars that are resistant to PHS.
查看更多>>摘要：Plants are highly susceptible to abiotic stresses,particularly heat stress during the reproductive stage.However,the specific molecular mechanisms underlying this sensitivity remain largely unknown.In the current study,we demonstrate that the Nuclear Transcription Factor,X-box Binding Protein 1-Like 1(NFXL1),directly regulates the expression of DEHYDRATION-RESPONSIVE ELEMENT-BINDING PROTEIN 2A(DREB2A),which is crucial for re-productive thermotolerance in Arabidopsis.NFXL1 is upregulated by heat stress,and its mutation leads to a reduction in silique length(seed number)under heat stress conditions.RNA-Seq analysis reveals that NFXL1 has a global impact on the expression of heat stress responsive genes,including DREB2A,Heat Shock Factor A3(HSFA3)and Heat Shock Protein 17.6(HSP17.6)in flower buds.Interestingly,NFXL1 is enriched in the promoter region of DREB2A,but not of either HSFA3 or HSP17.6.Further experiments using electrophoretic mobility shift assay have confirmed that NFXL1 directly binds to the DNA fragment derived from the DREB2A promoter.Moreover,effector-reporter assays have shown that NFXL1 activates the DREB2A promoter.The DREB2A mutants are also heat stress sensitive at the reproductive stage,and DEREB2A is epistatic to NFXL1 in regulating thermotolerance in flower buds.It is known that HSFA3,a direct target of DREB2A,regulates the expression of heat shock proteins genes under heat stress conditions.Thus,our findings establish NFXL1 as a critical up-stream regulator of DREB2A in the transcriptional cassette responsible for heat stress responses required for reproductive thermotolerance in Arabi-dopsis.
查看更多>>摘要：RNA-binding proteins(RBPs)are components of the post-transcriptional regulatory system,but their reg-ulatory effects on complex traits remain unknown.Using an integrated strategy involving map-based cloning,functional characterizations,and tran-scriptomic and population genomic analyses,we re-vealed that RBP-K(LOC_Os08g23120),RBP-A(LO-C_Os11g41890),and RBP-J(LOC_Os10g33230)encode proteins that form an RBP-A-J-K complex that negatively regulates rice yield-related traits.Ex-aminations of the RBP-A-J-K complex indicated RBP-K functions as a relatively non-specific RBP chaperone that enables RBP-A and RBP-J to func-tion normally.Additionally,RBP-J most likely affects GA pathways,resulting in considerable increases in grain and panicle lengths,but decreases in grain width and thickness.In contrast,RBP-A negatively regulates the expression of genes most likely in-volved in auxin-regulated pathways controlling cell wall elongation and carbohydrate transport,with substantial effects on the rice grain filling process as well as grain length and weight.Evolutionarily,RBP-K is relatively ancient and highly conserved,whereas RBP-J and RBP-A are more diverse.Thus,the RBP-A-J-K complex may represent a typical functional model for many RBPs and protein complexes that function at transcriptional and post-transcriptional levels in plants and animals for increased functional consistency,efficiency,and versatility,as well as in-creased evolutionary potential.Our results clearly demonstrate the importance of RBP-mediated post-transcriptional regulation for the diversity of complex traits.Furthermore,rice grain yield and quality may be enhanced by introducing various complete or partial loss-of-function mutations to specific RBP genes using clustered regularly interspaced palin-dromic repeats(CRISPR)/CRISPR-associated protein 9 technology and by exploiting desirable natural tri-genic allelic combinations at the loci encoding the components of the RBP-A-J-K complex through marker-assisted selection.
查看更多>>摘要：Secondary vascular tissue(SVT)development and regeneration are regulated by phytohormones.In this study,we used an in vitro SVT regeneration system to demonstrate that gibberellin(GA)treatment sig-nificantly promotes auxin-induced cambium rees-tablishment.Altering GA content by overexpressing or knocking down ent-kaurene synthase(KS)af-fected secondary growth and SVT regeneration in poplar.The poplar DELLA gene GIBBERELLIC ACID INSENSITIVE(PtoGAI)is expressed in a specific pattern during secondary growth and cambium re-generation after girdling.Overexpression of PtoGAI disrupted poplar growth and inhibited cambium regeneration,and the inhibition of cambium re-generation could be partially restored by GA appli-cation.Further analysis of the PtaDR5:GUS trans-genic plants,the localization of PIN-FORMED 1(PIN1)and the expression of auxin-related genes found that an additional GA treatment could enhance the auxin response as well as the expression of PIN1,which mediates auxin transport during SVT re-generation.Taken together,these findings suggest that GA promotes cambium regeneration by stim-ulating auxin signal transduction.
Hayeon KimHye Won KangDae Yeon HwangNayoung Lee...
103-120页
查看更多>>摘要：In order to flower in the appropriate season,plants monitor light and temperature changes and alter downstream pathways that regulate florigen genes such as Arabidopsis(Arabidopsis thaliana)FLOWERING LOCUS T(FT).In Arabidopsis,FT messenger RNA levels peak in the morning and evening under natural long-day conditions(LDs).However,the regulatory mechanisms governing morning FT induction remain poorly understood.The morning FT peak is absent in typical labo-ratory LDs characterized by high red:far-red light(R:FR)ratios and constant temperatures.Here,we demonstrate that ZEITLUPE(ZTL)interacts with the FT repressors TARGET OF EATs(TOEs),thereby repressing morning FT expression in natural environments.Under LDs with simulated sunlight(R:FR=1.0)and daily temperature cycles,which are natural LD-mimicking environmental conditions,FT transcript levels in the ztl mutant were high specifically in the morning,a pattern that was mirrored in the toe1 toe2 double mutant.Low night-to-morning temperatures increased the inhibitory effect of ZTL on morning FT expression by increasing ZTL protein levels early in the morning.Far-red light counteracted ZTL activity by decreasing its abundance(possibly via phyto-chrome A(phyA))while increasing GIGANTEA(GI)levels and negatively affecting the formation of the ZTL-GI complex in the morning.Therefore,the phyA-mediated high-irradiance response and GI play pivotal roles in morning FT induction.Our findings suggest that the delicate balance be-tween low temperature-mediated ZTL activity and the far-red light-mediated functions of phyA and GI offers plants flexibility in fine-tuning their flowering time by controlling FT expression in the morning.
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