Cytokinin-responsive RhRR1-RhSCL28 transcription factor module positively regulates petal size by promoting cell division in rose.

Petal size, a crucial trait in the economically important ornamental rose (Rosa hybrida), is synergistically regulated by cell division and cell expansion. Cell division primarily occurs during the early development of petals. However, the molecular mechanism underlying the regulation of petal size is far from clear. In this study, we isolated the transcription factor gene RhSCL28, which is highly expressed at the early stage of rose petal development and is induced by cytokinin. Silencing RhSCL28 resulted in a reduced final petal size and reduced cell number in rose petals. Further analysis showed that RhSCL28 participates in the regulation of cell division by positively regulating the expression of the cyclin genes RhCYCA1;1 and RhCYCB1;2. To explore the potential mechanism for cytokinin-mediated regulation of RhSCL28 expression, we investigated the cytokinin response factor RhRR1 and determined that it positively regulates RhSCL28 expression. Like RhSCL28, silencing RhRR1 also resulted in smaller petals by decreasing cell number. Taken together, these results reveal that the RhRR1-RhSCL28 module positively regulates petal size by promoting cell division in rose.

RhMYC2 controls petal size through synergistic regulation of jasmonic acid and cytokinin signaling in rose.

Petal size is determined by cell division and cell expansion. Jasmonic acid (JA) has been reported to be associated with floral development, but its regulatory mechanism affecting petal size remains unclear. Here, we reveal the vital role of JA in regulating petal size and the duration of the cell division phase via the key JA signaling component RhMYC2. We show that RhMYC2 expression is induced by exogenous treatment with methyl jasmonate and decreases from stage 0 to stage 2 of flower organ development, corresponding to the cell division phase. Furthermore, silencing RhMYC2 shortened the duration of the cell division phase, ultimately accelerating flowering opening and resulting in smaller petals. In addition, we determined that RhMYC2 controls cytokinin homeostasis in rose petals by directly activating the expression of the cytokinin biosynthetic gene LONELY GUY3 (RhLOG3) and repressing that of the cytokinin catabolism gene CYTOKININ OXIDASE/DEHYDROGENASE6 (RhCKX6). Silencing RhLOG3 shortened the duration of the cell division period and produced smaller petals, similar to RhMYC2 silencing. Our results underscore the synergistic effects of JA and cytokinin in regulating floral development, especially for petal size in roses.

AGAMOUS-LIKE 24 senses continuous inductive photoperiod in the inflorescence meristem to promote anthesis in chrysanthemum.

During the floral transition, many plant species including chrysanthemum (Chrysanthemum morifolium) require continuous photoperiodic stimulation for successful anthesis. Insufficient photoperiodic stimulation results in flower bud arrest or even failure. The molecular mechanisms underlying how continuous photoperiodic stimulation promotes anthesis are not well understood. Here, we reveal that in wild chrysanthemum (C. indicum), an obligate short-day (SD) plant, floral evocation is not limited to SD conditions. However, SD signals generated locally in the inflorescence meristem (IM) play a vital role in ensuring anthesis after floral commitment. Genetic analyses indicate that the florigen FLOWERING LOCUS T-LIKE3 (CiFTL3) plays an important role in floral evocation, but a lesser role in anthesis. Importantly, our data demonstrate that AGAMOUS-LIKE 24 (CiAGL24) is a critical component of SD signal perception in the IM to promote successful anthesis, and that floral evocation and anthesis are two separate developmental events in chrysanthemum. We further reveal that the central circadian clock component PSEUDO-RESPONSE REGULATOR 7 (CiPRR7) in the IM activates CiAGL24 expression in response to SD conditions. Moreover, our findings elucidate a negative feedback loop in which CiAGL24 and SUPPRESSOR OF OVEREXPRESSION OF CO 1 (CiSOC1) modulate LEAFY (CiLFY) expression. Together, our results demonstrate that the CiPRR7-CiAGL24 module is vital for sustained SD signal perception in the IM to ensure successful anthesis in chrysanthemum.

NtWIN1 regulates the biosynthesis of scopoletin and chlorogenic acid by targeting NtF6'H1 and NtCCoAMT genes in Nicotiana tabacum.

Scopoletin and chlorogenic acid (CGA) are important polyphenols that regulate plant growth, development, and stress resistance. The ERF transcription factor WAX INDUCER1 (WIN1) promotes the biosynthesis of cutin, suberine, and wax. However, its full roles in regulating the accumulation of plant secondary metabolites still remain to be further clarified. In this study, NtWIN1 gene encoding a SHINE-type AP2/ERF transcription factor of the Va subgroup was identified from N. tabacum. NtWIN1 showed high expression levels in tobacco stems, sepals, and pistils. Overexpression (OE) and knock-out of NtWIN1 showed that it promoted the accumulation of total polyphenols and altered their composition. Compare to that of WT plants, the CGA contents significantly increased by 25%-50% in the leaves, flowers, and capsules of OE lines, while the scopoletin contents in the OE plants significantly decreased by 30%-67%. In contrast, the CGA contents in ntwin1 lines reduced by 23%-26%, and the scopoletin contents in ntwin1 increased by 38%-75% compare to that of WT plants. Chromatin immunoprecipitation and Dual-Luc transcription activation assays showed that NtWIN1 could bind to the promoters of NtF6'H1 and NtCCoAMT, thereby modulating their expression. The scopoletin content in ntwin1/ntf6'h1 double mutant was significantly lower than that in ntwin1 and WT plants, but showed no significant differences with that in ntf6'h1 mutant, further indicating that the inhibition of NtWIN1 on scopoletin accumulation depends on the activity of NtF6'H1. Our study illustrates the new roles of NtWIN1, and provides a possible target for regulating the synthesis of polyphenols in tobacco.

Multi-omics analysis reveals key regulatory defense pathways and genes involved in salt tolerance of rose plants.

Salinity stress causes serious damage to crops worldwide, limiting plant production. However, the metabolic and molecular mechanisms underlying the response to salt stress in rose (Rosa spp.) remain poorly studied. We therefore performed a multi-omics investigation of Rosa hybrida cv. Jardin de Granville (JDG) and Rosa damascena Mill. (DMS) under salt stress to determine the mechanisms underlying rose adaptability to salinity stress. Salt treatment of both JDG and DMS led to the buildup of reactive oxygen species (H2O2). Palisade tissue was more severely damaged in DMS than in JDG, while the relative electrolyte permeability was lower and the soluble protein content was higher in JDG than in DMS. Metabolome profiling revealed significant alterations in phenolic acid, lipids, and flavonoid metabolite levels in JDG and DMS under salt stress. Proteome analysis identified enrichment of flavone and flavonol pathways in JDG under salt stress. RNA sequencing showed that salt stress influenced primary metabolism in DMS, whereas it substantially affected secondary metabolism in JDG. Integrating these datasets revealed that the phenylpropane pathway, especially the flavonoid pathway, is strongly enhanced in rose under salt stress. Consistent with this, weighted gene coexpression network analysis (WGCNA) identified the key regulatory gene chalcone synthase 1 (CHS1), which is important in the phenylpropane pathway. Moreover, luciferase assays indicated that the bHLH74 transcription factor binds to the CHS1 promoter to block its transcription. These results clarify the role of the phenylpropane pathway, especially flavonoid and flavonol metabolism, in the response to salt stress in rose.

TSPO-induced degradation of the ethylene receptor RhETR3 promotes salt tolerance in rose (Rosa hybrida).

The gaseous plant hormone ethylene regulates plant development, growth, and responses to stress. In particular, ethylene affects tolerance to salinity; however, the underlying mechanisms of ethylene signaling and salt tolerance are not fully understood. Here, we demonstrate that salt stress induces the degradation of the ethylene receptor ETHYLENE RESPONSE 3 (RhETR3) in rose (Rosa hybrid). Furthermore, the TspO/MBR (Tryptophan-rich sensory protein/mitochondrial benzodiazepine receptor) domain-containing membrane protein RhTSPO interacted with RhETR3 to promote its degradation in response to salt stress. Salt tolerance is enhanced in RhETR3-silenced rose plants but decreased in RhTSPO-silenced plants. The improved salt tolerance of RhETR3-silenced rose plants is partly due to the increased expression of ACC SYNTHASE1 (ACS1) and ACS2, which results in an increase in ethylene production, leading to the activation of ETHYLENE RESPONSE FACTOR98 (RhERF98) expression and, ultimately accelerating H2O2 scavenging under salinity conditions. Additionally, overexpression of RhETR3 increased the salt sensitivity of rose plants. Co-overexpression with RhTSPO alleviated this sensitivity. Together, our findings suggest that RhETR3 degradation is a key intersection hub for the ethylene signalling-mediated regulation of salt stress.

Evaluation of aphid resistance on different rose cultivars and transcriptome analysis in response to aphid infestation.

BACKGROUND: The rose is one of the most important ornamental flowers in the world for its aesthetic beauty but can be attacked by many pests such as aphids. Aphid infestation causes tremendous damage on plant tissues leading to harmed petals and leaves. Rose cultivars express different levels of resistance to aphid infestation yet the information remains unclear. Not only that, studies about the transcriptional analysis on defending mechanisms against aphids in rose are limited so far. RESULTS: In this study, the aphid resistance of 20 rose cultivars was evaluated, and they could be sorted into six levels based on the number ratio of aphids. And then, a transcriptome analysis was conducted after aphid infestation in one high resistance (R, Harmonie) and one highly susceptibility (S, Carefree Wonder) rose cultivar. In open environment the majority of rose cultivars had the highest aphid number at May 6th or May 15th in 2020 and the resistance to infestation could be classified into six levels. Differential expression analysis revealed that there were 1,626 upregulated and 767 downregulated genes in the R cultivar and 481 upregulated and 63 downregulated genes in the S cultivar after aphid infestation. Pathway enrichment analysis of the differentially expressed genes revealed that upregulated genes in R and S cultivars were both enriched in defense response, biosynthesis of secondary metabolites (phenylpropanoid, alkaloid, and flavonoid), carbohydrate metabolism (galactose, starch, and sucrose metabolism) and lipid processing (alpha-linolenic acid and linolenic acid metabolism) pathways. In the jasmonic acid metabolic pathway, linoleate 13S-lipoxygenase was specifically upregulated in the R cultivar, while genes encoding other crucial enzymes, allene oxide synthase, allene oxide cyclase, and 12-oxophytodienoate reductase were upregulated in both cultivars. Transcription factor analysis and transcription factor binding search showed that WRKY transcription factors play a pivotal role during aphid infestation in the R cultivar. CONCLUSIONS: Our study indicated the potential roles of jasmonic acid metabolism and WRKY transcription factors during aphid resistance in rose, providing clues for future research.

The transcription factor RhMYB17 regulates the homeotic transformation of floral organs in rose (Rosa hybrida) under cold stress.

Low temperatures affect flower development in rose (Rosa hybrida), increasing petaloid stamen number and reducing normal stamen number. We identified the low-temperature-responsive R2R3-MYB transcription factor RhMYB17, which is homologous to Arabidopsis MYB17 by similarity of protein sequences. RhMYB17 was up-regulated at low temperatures, and RhMYB17 transcripts accumulated in floral buds. Transient silencing of RhMYB17 by virus-induced gene silencing decreased petaloid stamen number and increased normal stamen number. According to the ABCDE model of floral organ identity, class A genes APETALA 1 (AP1) and AP2 contribute to sepal and petal formation. Transcription factor binding analysis identified RhMYB17 binding sites in the promoters of rose APETALA 2 (RhAP2) and APETALA 2-LIKE (RhAP2L). Yeast one-hybrid assays, dual-luciferase reporter assays, and electrophoretic mobility shift assays confirmed that RhMYB17 directly binds to the promoters of RhAP2 and RhAP2L, thereby activating their expression. RNA sequencing further demonstrated that RhMYB17 plays a pivotal role in regulating the expression of class A genes, and indirectly influences the expression of the class C gene. This study reveals a novel mechanism for the homeotic transformation of floral organs in response to low temperatures.

The F-box protein RhSAF destabilizes the gibberellic acid receptor RhGID1 to mediate ethylene-induced petal senescence in rose.

Roses are among the most popular ornamental plants cultivated worldwide for their great economic, symbolic, and cultural importance. Nevertheless, rapid petal senescence markedly reduces rose (Rosa hybrida) flower quality and value. Petal senescence is a developmental process tightly regulated by various phytohormones. Ethylene accelerates petal senescence, while gibberellic acid (GA) delays this process. However, the molecular mechanisms underlying the crosstalk between these phytohormones in the regulation of petal senescence remain largely unclear. Here, we identified SENESCENCE-ASSOCIATED F-BOX (RhSAF), an ethylene-induced F-box protein gene encoding a recognition subunit of the SCF-type E3 ligase. We demonstrated that RhSAF promotes degradation of the GA receptor GIBBERELLIN INSENSITIVE DWARF1 (RhGID1) to accelerate petal senescence. Silencing RhSAF expression delays petal senescence, while suppressing RhGID1 expression accelerates petal senescence. RhSAF physically interacts with RhGID1s and targets them for ubiquitin/26S proteasome-mediated degradation. Accordingly, ethylene-induced RhGID1C degradation and RhDELLA3 accumulation are compromised in RhSAF-RNAi lines. Our results demonstrate that ethylene antagonizes GA activity through RhGID1 degradation mediated by the E3 ligase RhSAF. These findings enhance our understanding of the phytohormone crosstalk regulating petal senescence and provide insights for improving flower longevity.

Scaffold protein BTB/TAZ domain-containing genes (CmBTs) play a negative role in root development of chrysanthemum.

Scaffold proteins, which are known as hubs controlling information flow in cells, can function in a diverse array of biological processes in plants. The BTB/TAZ domain-containing scaffold proteins are associated with multiple signaling pathways in plants. However, there have been few studies of the roles of BT scaffold proteins in chrysanthemum to date. In this study, four CmBT genes named as CmBT1, CmBT1-LIKE1 (CmBT1L1), CmBT1-LIKE2 (CmBT1L2), and CmBT5 were cloned based our previous RNA-seq database. The four CmBT genes showed distinctive expression patterns both in different tissues and in response to different stimuli, such as light, sugar, nitrate and auxin. Knockdown of the four CmBTs facilitated the development of adventitious roots and root hair in chrysanthemum. Transcriptome sequencing analysis revealed thousands of differentially expressed genes after knockdown of the four CmBT genes. Moreover, functional annotation suggested that CmBTs play a tethering role as scaffold proteins. Our findings reveal that CmBTs can negatively regulate root development of chrysanthemum by mediating nitrate assimilation, amino acid biosynthesis, and auxin and jasmonic acid (JA) signaling pathways. This study provides new insights into the role of CmBTs in root development of chrysanthemum.

Effect of biochar on biochemical properties of saline soil and growth of rice.

To amend physical properties of coastal saline soil for rice production, six biochar treatments (0, 0.5, 1, 2, 4 and 6 kg biochar per m2 soil) were set up as CK, T1, T2, T3, T4 and T5, respectively and their effect on the biochemical properties of coastal saline soil and rice growth characteristics were evaluated in a barrel planting experiment. The results showed that compared with CK (with no biochar added), the soil EC of T1 and T2-T5 was reduced by 11.5 %, but increased by 8.8-62.9 %, respectively. The available potassium and organic matter contents of T1-T5 increased ranging from 3.7-10.2 % to 8.0-46.8 %, respectively. With the increase of the biochar amount, the urease activity of soil in the 0-10 cm deep soil showed an increasing trend by 194.8-744.6 % with T1-T5, compared with that of the CK treatment. The activity of alkaline phosphatase in soil increased first and then decreased, and its increment with T1-T5 was between 28.2 and 64.8 % in comparison with that of CK. With more biochar added to soil, the leaf dry weight, root dry weight, total dry matter mass, total root length, single panicle quality and weight per 100 grains showed a trend of increase first and then decrease. The highest incremental values of all measurements were obtained with T1 by 21.8 %, 23.9 %, 13.8 %, 33.9 %, 30.8 % and 11.6 % respectively, compared with those with CK. However, adding biochar in soil demonstrated insignificant effect on the weight of single panicle, panicle length, stem thickness, tillers, setting rate, soil hydrolyzable nitrogen, available phosphorus content, rice protein, amylose, and taste quality among all treatments. In summary, the application of 0.5 kg m-2 biochar can improve the biochemical properties of saline soil and therefore increase rice yield.

Transcription factor RhRAP2.4L orchestrates cell proliferation and expansion to control petal size in rose.

Maintaining proper flower size is vital for plant reproduction and adaption to the environment. Petal size is determined by spatiotemporally regulated cell proliferation and expansion. However, the mechanisms underlying the orchestration of cell proliferation and expansion during petal growth remains elusive. Here, we determined that the transition from cell proliferation to expansion involves a series of distinct and overlapping processes during rose (Rosa hybrida) petal growth. Changes in cytokinin content were associated with the transition from cell proliferation to expansion during petal growth. RNA sequencing identified the AP2/ERF transcription factor gene RELATED TO AP2 4-LIKE (RhRAP2.4L), whose expression pattern positively associated with cytokinin levels during rose petal development. Silencing RhRAP2.4L promoted the transition from cell proliferation to expansion and decreased petal size. RhRAP2.4L regulates cell proliferation by directly repressing the expression of KIP RELATED PROTEIN 2 (RhKRP2), encoding a cell cycle inhibitor. In addition, we also identified BIG PETALub (RhBPEub) as another direct target gene of RhRAP2.4L. Silencing RhBPEub decreased cell size, leading to reduced petal size. Furthermore, the cytokinin signaling protein ARABIDOPSIS RESPONSE REGULATOR 14 (RhARR14) activated RhRAP2.4L expression to inhibit the transition from cell proliferation to expansion, thereby regulating petal size. Our results demonstrate that RhRAP2.4L performs dual functions in orchestrating cell proliferation and expansion during petal growth.

Petal size is controlled by the MYB73/TPL/HDA19-miR159-CKX6 module regulating cytokinin catabolism in Rosa hybrida.

The size of plant lateral organs is determined by well-coordinated cell proliferation and cell expansion. Here, we report that miR159, an evolutionarily conserved microRNA, plays an essential role in regulating cell division in rose (Rosa hybrida) petals by modulating cytokinin catabolism. We uncover that Cytokinin Oxidase/Dehydrogenase6 (CKX6) is a target of miR159 in petals. Knocking down miR159 levels results in the accumulation of CKX6 transcripts and earlier cytokinin clearance, leading to a shortened cell division period and smaller petals. Conversely, knocking down CKX6 causes cytokinin accumulation and a prolonged developmental cell division period, mimicking the effects of exogenous cytokinin application. MYB73, a R2R3-type MYB transcription repressor, recruits a co-repressor (TOPLESS) and a histone deacetylase (HDA19) to form a suppression complex, which regulates MIR159 expression by modulating histone H3 lysine 9 acetylation levels at the MIR159 promoter. Our work sheds light on mechanisms for ensuring the correct timing of the exit from the cell division phase and thus organ size regulation by controlling cytokinin catabolism.

Disruption of the Contents of Endogenous Hormones Cause Pollen Development Obstruction and Abortion in Male-Sterile Hybrid Lily Populations.

Lilies are well-known flowers with large anthers and a high quantity of pollen that easily contaminates clothing and tepals. The anthers need to be artificially removed, leading to production problems. Cultivating male-sterile or pollen-free lilies could solve these problems. The key period of male sterility in a specific male-sterile hybrid lily population was determined through cytological observation. The contents of hormones, soluble sugar, soluble protein, and proline were determined by high-performance liquid chromatography, tandem mass spectrometry and colorimetry. Transcriptome sequencing was used to identify the genes with altered expression. The key period of male sterility was determined to be the microspore mother and tetrad stages. The hormone contents were abnormal in the sterile line compared with the fertile line. The indole-3-acetic acid (IAA) content was higher in the sterile line than in the fertile line at all stages, while the gibberellic acid 4 (GA4) content showed the opposite result. Abscisic acid (ABA) accumulated in the sterile line in both the microspore mother and tetrad stages, and the zeatin riboside (ZR) content in the sterile line increased at the microspore mother stage but decreased at the tetrad stage. The contents of soluble sugar, soluble protein and proline were higher in the fertile line than in the sterile line. Genes involved in auxin and ABA synthesis and signalling pathways were highly expressed in the male-sterile line. Our data suggested that abnormal contents of hormones in the microspore mother and tetrad stages resulted in pollen abortion in a male-sterile hybrid lily population, which indicated that the hormone balance in specific stages plays critical functions in pollen development in lilies.

Genome-Wide Identification and Expression Analysis of Lipoxygenase Genes in Rose (Rosa chinensis).

Lipoxygenases (LOX) play pivotal roles in plant resistance to stresses. However, no study has been conducted on LOX gene identification at the whole genome scale in rose (Rosa chinensis). In this study, a total of 17 RcLOX members were identified in the rose genome. The members could be classified into three groups: 9-LOX, Type I 13-LOX, and Type II 13-LOX. Similar gene structures and protein domains can be found in RcLOX members. The RcLOX genes were spread among all seven chromosomes, with unbalanced distributions, and several tandem and proximal duplication events were found among RcLOX members. Expressions of the RcLOX genes were tissue-specific, while every RcLOX gene could be detected in at least one tissue. The expression levels of most RcLOX genes could be up-regulated by aphid infestation, suggesting potential roles in aphid resistance. Our study offers a systematic analysis of the RcLOX genes in rose, providing useful information not only for further gene cloning and functional exploration but also for the study of aphid resistance.

PHOTOLYASE/BLUE LIGHT RECEPTOR2 regulates chrysanthemum flowering by compensating for gibberellin perception.

The gibberellins (GAs) receptor GA INSENSITIVE DWARF1 (GID1) plays a central role in GA signal perception and transduction. The typical photoperiodic plant chrysanthemum (Chrysanthemum morifolium) only flowers when grown in short-day photoperiods. In addition, chrysanthemum flowering is also controlled by the aging pathway, but whether and how GAs participate in photoperiod- and age-dependent regulation of flowering remain unknown. Here, we demonstrate that photoperiod affects CmGID1B expression in response to GAs and developmental age. Moreover, we identified PHOTOLYASE/BLUE LIGHT RECEPTOR2, an atypical photocleavage synthase, as a CRYPTOCHROME-INTERACTING bHLH1 interactor with which it forms a complex in response to short days to activate CmGID1B transcription. Knocking down CmGID1B raised endogenous bioactive GA contents and GA signal perception, in turn modulating the expression of the aging-related genes MicroRNA156 and SQUAMOSA PROMOTER BINDING PROTEIN-LIKE3. We propose that exposure to short days accelerates the juvenile-to-adult transition by increasing endogenous GA contents and response to GAs, leading to entry into floral transformation.

Phylotranscriptomics supports numerous polyploidization events and phylogenetic relationships in Nicotiana.

Introduction: Nicotiana L. (Solanaceae) is of great scientific and economic importance, and polyploidization has been pivotal in shaping this genus. Despite many previous studies on the Nicotiana phylogenetic relationship and hybridization, evidence from whole genome data is still lacking. Methods: In this study, we obtained 995 low-copy genes and plastid transcript fragments from the transcriptome datasets of 26 Nicotiana species, including all sections. We reconstructed the phylogenetic relationship and phylogenetic network of diploid species. Results: The incongruence among gene trees showed that the formation of N. sylvestris involved incomplete lineage sorting. The nuclear-plastid discordance and nuclear introgression absence indicated that organelle capture from section Trigonophyllae was involved in forming section Petunioides. Furthermore, we analyzed the evolutionary origin of polyploid species and dated the time of hybridization events based on the analysis of PhyloNet, sequence similarity search, and phylogeny of subgenome approaches. Our results highly evidenced the hybrid origins of five polyploid sections, including sections Nicotiana, Repandae, Rusticae, Polydicliae, and Suaveolentes. Notably, we provide novel insights into the hybridization event of section Polydicliae and Suaveolentes. The section Polydicliae formed from a single hybridization event between maternal progenitor N. attenuata and paternal progenitor N. undulata; the N. sylvestris (paternal progenitor) and the N. glauca (maternal progenitor) were involved in the formation of section Suaveolentes. Discussion: This study represents the first exploration of Nicotiana polyploidization events and phylogenetic relationships using the high-throughput RNA-seq approach. It will provide guidance for further studies in molecular systematics, population genetics, and ecological adaption studies in Nicotiana and other related species.

Overexpression of a nitrate transporter NtNPF2.11 increases nitrogen accumulation and yield in tobacco.

Nitrogen (N) is the key essential macronutrient for crop growth and yield. Over-application of inorganic N fertilizer in fields generated serious environmental pollution and had a negative impact to human health. Therefore, improving crop N use efficiency (NUE) is helpful for sustainable agriculture. The biological functions of nitrogen transporters and regulators have been intensively studied in many crop species. However, only a few nitrogen transporters have been identified in tobacco to date. We reported the identification and functional characterization of a nitrate transporter NtNPF2.11 from tobacco (Nicotiana tabacum). qRT-PCR assay revealed that NtNPF2.11 was mainly expressed in leaf and vein. Under middle N (MN, 1.57 kg N/100 m2) and high N (HN, 2.02 kg N/100 m2) conditions, overexpression of NtNPF2.11 in tobacco greatly improved N utilization and biomass. Moreover, under middle N and high N conditions, the expression of genes for nitrate assimilation, such as NtNR1, NtNiR, NtGS and NtGOGAT, were upregulated in NtNPF2.11 overexpression plants. Compared with WT, overexpression of NtNPF2.11 increased potassium (K) accumulation under high N conditions. These results indicated that overexpression of NtNPF2.11 could increase tobacco yield, N and K accumulation under higher N conditions. Overall, these findings improve our understanding the function of NtNPF2.11 and provide useful gene for sustainable agriculture.

The CALCINEURIN B-LIKE 4/CBL-INTERACTING PROTEIN 3 module degrades repressor JAZ5 during rose petal senescence.

Flower senescence is genetically regulated and developmentally controlled. The phytohormone ethylene induces flower senescence in rose (Rosa hybrida), but the underlying signaling network is not well understood. Given that calcium regulates senescence in animals and plants, we explored the role of calcium in petal senescence. Here, we report that the expression of calcineurin B-like protein 4 (RhCBL4), which encodes a calcium receptor, is induced by senescence and ethylene signaling in rose petals. RhCBL4 interacts with CBL-interacting protein kinase 3 (RhCIPK3), and both positively regulate petal senescence. Furthermore, we determined that RhCIPK3 interacts with the jasmonic acid response repressor jasmonate ZIM-domain 5 (RhJAZ5). RhCIPK3 phosphorylates RhJAZ5 and promotes its degradation in the presence of ethylene. Our results reveal that the RhCBL4-RhCIPK3-RhJAZ5 module mediates ethylene-regulated petal senescence. These findings provide insights into flower senescence, which may facilitate innovations in postharvest technology for extending rose flower longevity.

New insights into the degradation mechanism and risk assessment of HFPO-DA by advanced oxidation processes based on activated persulfate in aqueous solutions.

Hexafluoropropylene oxide dimer acid (HFPO-DA) is widely used as a substitute for perfluorooctanoic acid (PFOA). HFPO-DA exhibits high water solubility and low adsorption potential, conferring significant fluidity in aquatic environments. Given that the toxicity of HFPO-DA is similar to PFOA, it is necessary to control its content in aquatic environments. Electrochemical and thermally-activated persulfates have been successfully used to degrade HFPO-DA, but UV-activated persulfates cannot degrade the compound. Given that research on degradation mechanisms is still incomplete and lacks kinetic research, the mechanism and kinetic calculations of oxidative degradation were studied in detail using DFT calculations. And the toxicity of HFPO-DA degradation intermediates and products was evaluated to reveal the feasibility of using advanced oxidation process (AOP) technology based on persulfate to degrade HFPO-DA in wastewater. The results showed that the committed step of HFPO-DA degradation was initiated by the electron transfer reaction of SO4•- radicals. This reaction is not spontaneous at room temperature and requires sufficient electrical or thermal energy to be absorbed from the external environment. The perfluoroalcohol produced during this reaction can subsequently undergo four possible reactions: H atom abstraction from alcohol groups by an OH radical; H atom abstraction by SO4•-; direct HF removal; and HF removal with water as the catalyst. The final degradation products of HFPO-DA mainly include CO2, CF3CF2COOH, CF3COOH, FCOOH and HF, which has been identified through previous experimental analysis. Ecotoxicity assessment indicates that degradation does not produce highly toxic intermediates, and that the final products are non-toxic, supporting the feasibility of persulfate-based AOP technologies.