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In agroecosystems, effective straw return modes are one of the key practices for increasing soil fertility and carbon (C) availability. Although they improve soil quality, there is currently little information available regarding the influence of distinct straw return modes with respect to potential soil organic carbon (SOC) sequestration. In this study, we established a five-year (2015–2019) field experiment in Mollisols of Northeast China, which included four straw return modes, plow tillage with straw return as the control (PTS), rotary tillage with straw return (RTS), rotary tillage with straw strip return (RSS), and plow tillage with straw strip return (PSS), to investigate the impact on soil physicochemical properties, aggregates, and C sequestration. The results reveal that RSS effectively improved the soil physicochemical properties. Such responses increased the contents of SOC, fulvic acid carbon (FAC), and humin carbon (HMC) in all soil layers (0–30 cm). The proportion of macroaggregates was higher in RSS, whereas the proportion of silt/clay was the lowest at depths of 0–20 cm; consequently, the mean weight diameter (MWD) and geometric mean diameter (GMD) of RSS were higher at depths of 0–20 cm due to the improved physical soil structure. In the 0–10 cm and 20–30 cm layers, the highest humic acid carbon (HAC) concentrations associated with all aggregate sizes were found for RSS, in contrast to 10–20 cm, which had increased HMC. Structural equation modeling (SEM) revealed that C transformation was mainly mediated through silt/clay-associated FAC, HMC, and SOC, ultimately determining HAC (81%) and HMC (85%) as the primary humus fractions for SOC sequestration. Therefore, this study shows that RSS is the suitable straw return mode for effectively improving soil quality, aggregate stability, and C sequestration in Mollisols of Northeast China. [ABSTRACT FROM AUTHOR]

Abstract Phytochrome B (phyB), the primary red light photoreceptor, promotes photomorphogenesis in Arabidopsis by interacting with the basic helix-loop-helix transcriptional factor PIF3 and inducing its phosphorylation and degradation. Heterotrimeric G proteins are known to regulate various developmental processes in plants and animals. In Arabidopsis , the G-protein β subunit AGB1 is known to repress photomorphogenesis. However, whether and how phyB and AGB1 coordinately regulate photomorphogenesis are largely unknown. Here we show that phyB physically interacts with AGB1 in a red light-dependent manner and that AGB1 interacts directly with PIF3. Moreover, we demonstrate that the AGB1–PIF3 interaction inhibits the association of PIF3 with phyB, leading to reduced phosphorylation and degradation of PIF3, whereas the phyB-AGB1 interaction represses the association of PIF3 with AGB1, resulting in enhanced phosphorylation and degradation of PIF3. Our results suggest that phyB and AGB1 antagonistically regulate PIF3 stability by dynamically interacting with each other and PIF3. This dynamic mechanism may allow plants to balance phyB and G-protein signaling to optimize photomorphogenesis. We find that AGB1 interacts with PIF3 to inhibit the association of PIF3 with phyB and its degradation, whereas phyB interacts with AGB1 to promote the dissociation of PIF3 from AGB1 and its degradation. This study reveals a dynamic signaling mechanism by which light and G protein coordinate the regulation of plant growth. [ABSTRACT FROM AUTHOR]

Abstract Light and the heterotrimeric G-protein are known to antagonistically regulate photomorphogenesis in Arabidopsis. However, whether light and G-protein coordinate the regulation of photomorphogenesis is largely unknown. Here we show that the blue light photoreceptor cryptochrome 1 (CRY1) physically interacts with the G-protein β subunit, AGB1, in a blue light-dependent manner. We also show that AGB1 directly interacts with HY5, a basic leucine zipper transcriptional factor that acts as a critical positive regulator of photomorphogenesis, to inhibit its DNA-binding activity. Genetic studies suggest that CRY1 acts partially through AGB1, and AGB1 acts partially through HY5 to regulate photomorphogenesis. Moreover, we demonstrate that blue light-triggered interaction of CRY1 with AGB1 promotes the dissociation of HY5 from AGB1. Our results suggest that the CRY1 signaling mechanism involves positive regulation of the DNA-binding activity of HY5 mediated by the CRY1–AGB1 interaction, which inhibits the association of AGB1 with HY5. We propose that the antagonistic regulation of HY5 DNA-binding activity by CRY1 and AGB1 may allow plants to balance light and G-protein signaling and optimize photomorphogenesis. The blue light photoreceptor cryptochrome 1 (CRY1) interacts with the G-protein β subunit AGB1 in a blue light-dependent manner. AGB1 interacts with HY5 to inhibit its DNA-binding activity and photomorphogenesis. Blue light-triggered interaction of CRY1 with AGB1 promotes the dissociation of AGB1 from HY5, suggesting that light and G protein coordinate regulation of photomorphogenesis through the antagonistic regulation of HY5 DNA-binding activity [ABSTRACT FROM AUTHOR]

Fruit color substantially affects consumer preferences, with darker red strawberries being economically more valuable due to their higher anthocyanin content. However, the molecular basis for the dark red coloration remains unclear. Through screening of an ethyl methanesulfonate mutant library, we identified a rg418 mutant, that demonstrated anthocyanin accumulation during early fruit development stages. Furthermore, the ripening fruits of this mutant had higher anthocyanin content than wild-type (WT) fruits. An analysis of flavonoid content in WT and rg418 mutant fruits revealed substantial changes in metabolic fluxes, with the mutant exhibiting increased levels of anthocyanins and flavonols and decreased levels of proanthocyanidins. Bulked sergeant analysis sequencing indicated that the mutant gene was anthocyanidin reductase (ANR), a key gene in the proanthocyanidin synthesis pathway. Furthermore, transcriptome sequencing revealed the increased expression of MYB105 during the early development stage of mutant fruits, which promoted the expression of UFGT (UDP-glucose flavonoid 3-O-glucosyltransferase), a key gene involved in anthocyanin synthesis, thus substantially enhancing the anthocyanin content in the mutant fruits. Additionally, mutating ANR in a white-fruited strawberry variant (myb10 mutant) resulted in appealing pink-colored fruits, suggesting the diverse roles of ANR in fruit color regulation. Our study provides valuable theoretical insights for improving strawberry fruit color. [ABSTRACT FROM AUTHOR]

Eggplant is rich in anthocyanins, which are the major secondary metabolites and beneficial to human health. We discovered that the anthocyanin biosynthesis of eggplant cultivar ‘Lanshan Hexian’ was regulated by light. In this study, we isolated two blue light receptor genes, SmCRY1 and SmCRY2 , and negative/positive anthocyanin regulatory factors SmCOP1 and SmHY5 from eggplant. In terms of transcript levels, SmCRY1 , SmCRY2 and SmHY5 were up-regulated by light, while SmCOP1 was down-regulated. Subsequently, the four genes were functionally complemented in phenotype of corresponding mutants, indicating that they act as counterparts of Arabidopsis genes. Yeast two-hybrid and bimolecular fluorescence complementation assays showed that SmCRY1 and SmCRY2 interact with SmCOP1 in a blue-light-dependent manner. It also obtained the result that SmCOP1 interacts with SmHY5 and SmMYB1. Furthermore, using yeast one-hybrid assay, we found that SmHY5 and SmMYB1 both bind the promoters of anthocyanin biosynthesis structural genes ( SmCHS and SmDFR ). Taken together, blue-light-triggered CRY1/CRY2-COP1 interaction creates the condition that HY5 and MYB1 combine with the downstream anthocyanin synthesis genes ( CHS and DFR ) in eggplant. Our finding provides a new working model by which light controls anthocyanin accumulation in eggplant. [ABSTRACT FROM AUTHOR]

Light is a key environmental cue that fundamentally regulates plant growth and development, which is mediated by the multiple photoreceptors including the blue light (BL) photoreceptor cryptochrome 1 (CRY1). The signaling mechanism of Arabidopsis thaliana CRY1 involves direct interactions with CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1)/SUPPRESSOR OF PHYA-105 1 and stabilization of COP1 substrate ELONGATED HYPOCOTYL 5 (HY5). H2A.Z is an evolutionarily conserved histone variant, which plays a critical role in transcriptional regulation through its deposition in chromatin catalyzed by SWR1 complex. Here we show that CRY1 physically interacts with SWC6 and ARP6, the SWR1 complex core subunits that are essential for mediating H2A.Z deposition, in a BL-dependent manner, and that BL-activated CRY1 enhances the interaction of SWC6 with ARP6. Moreover, HY5 physically interacts with SWC6 and ARP6 to direct the recruitment of SWR1 complex to HY5 target loci. Based on previous studies and our findings, we propose that CRY1 promotes H2A.Z deposition to regulate HY5 target gene expression and photomorphogenesis in BL through the enhancement of both SWR1 complex activity and HY5 recruitment of SWR1 complex to HY5 target loci, which is likely mediated by interactions of CRY1 with SWC6 and ARP6, and CRY1 stabilization of HY5, respectively. [ABSTRACT FROM AUTHOR]

Returning crop straw to soil can potentially improve soil health and crop production, facilitating sustainable agriculture. However, the effects of straw incorporation with various tillage management techniques combined with nitrogen (N) regimes on crop root growth, and water and N utility are not well understood. In this study, rotary tillage (RTS) and plow tillage (PTS) for straw incorporation combined with N regimes (CK, no N applied; LN, 112 kg N ha−1; MN, 187 kg N ha−1; and HN, 262 kg N ha−1) were used to determine their effects on soil water and mineral N availability, root distribution, crop N uptake, grain yield, and water use efficiency (WUE) of maize in northeast China. The results demonstrate that higher levels of pre-sowing soil-water storage and field evapotranspiration (ET), and lower levels of WUE and pre-sowing soil mineral N storage (Nmin-PS) at a depth of 0–60 cm were obtained with the RTS treatments as compared to the PTS treatments. N addition improved Nmin-PS and post-harvest soil mineral N storage (Nmin-PH) at a depth of 60–100 cm in 2016, and increased WUE compared to CK. RTS treatments enhanced root weight density (RWD) at a depth of 0–60 cm in 2016–2017, root length density (RLD), ratio of root length density (RLDR), and ratio of root weight density (RWDR) at a depth of 30–60 cm in 2016, and RLD at a depth of 0–30 cm in 2017. N addition promoted RLD and RWD at a depth of 0–10 cm in 2016–2017. RTS treatments reduced pre-silking shoot N uptake (NPS) and grain yield. Shoot N uptake and grain yield were enhanced in response to increasing levels of N; however, the grain yield did not show further significant improvements when the amount of N applied was over 187 kg N ha−1 (except for RTS in 2016). Overall, tillage with straw incorporation management and N levels markedly affected the soil physicochemical properties (such as ET, Nmin-PS, and Nmin-PH). This influenced grain yield indirectly by further mediating root traits (RLD, RWD, RLDR, and RWDR) with consequences for the NPS and post-silking shoot N uptake (NPOS) of maize, which were found to have greatest direct and positive impact on maize grain yield. [ABSTRACT FROM AUTHOR]

Anthocyanin accumulation is transcriptionally regulated by the MYB–bHLH–WD40 complex. Light is indispensable for anthocyanin accumulation, and light-inducible MYB and HY5 were considered to promote anthocyanin accumulation in many fruits. Whether and how light-inducible bHLH transcription factor and HY5 regulate anthocyanin synthesis in strawberry is unknown. In this study, we identified a bHLH transcription factor, FvbHLH9 , which was induced by light as well as FvHY5 , and found that, similar to FvHY5, the transient overexpression and interference FvbHLH9 in strawberry fruits can promote and decrease anthocyanin accumulation, respectively, indicating FvbHLH9 functions as a positive regulator of anthocyanin biosynthesis. Furthermore, we confirmed that both FvHY5 and FvbHLH9 specifically bind to the promoter region of some key enzyme genes, including FvDFR , and the expression of FvDFR was activated through the heterodimer formation between FvHY5 and FvbHLH9. Finally, we confirmed that FvbHLH9-promoted anthocyanin accumulation is dependent on HY5–bHLH heterodimerisation in Arabidopsis. Our findings provide insights into a mechanism involving the synergistic regulation of light-dependent coloration and anthocyanin biosynthesis via a HY5–bHLH heterodimer formed by the interaction of FvHY5 and FvbHLH9 in strawberry fruits. [ABSTRACT FROM AUTHOR]

Summary: Arabidopsis CRY1 and phyB are the primary blue and red light photoreceptors mediating blue and red light inhibition of hypocotyl elongation, respectively. Auxin is a pivotal phytohormone involved in promoting hypocotyl elongation. CRY1 and phyB interact with and stabilize auxin/indole acetic acid proteins (Aux/IAAs) to inhibit auxin signaling. The present study investigated whether photoreceptors might interact directly with Auxin Response Factors (ARFs) to regulate auxin signaling.Protein–protein interaction studies demonstrated that CRY1 and phyB interact physically with ARF6 and ARF8 through their N‐terminal domains in a blue and red light‐dependent manner, respectively. Moreover, the N‐terminal DNA‐binding domain of ARF6 and ARF8 is involved in mediating their interactions with CRY1.Genetic studies showed that ARF6 and ARF8 act partially downstream from CRY1 and PHYB to regulate hypocotyl elongation under blue and red light, respectively. Chromatin immunoprecipitation‐PCR assays demonstrated that CRY1 and phyB mediate blue and red light repression of the DNA‐binding activity of ARF6 and ARF6‐target gene expression, respectively.Altogether, the results herein suggest that the direct repression of auxin‐responsive gene expression mediated by the interactions of CRY1 and phyB with ARFs constitutes a new layer of the regulatory mechanisms by which light inhibits auxin‐induced hypocotyl elongation. [ABSTRACT FROM AUTHOR]

The accumulation of anthocyanins can be found in both the fruit and petioles of strawberries, but the fruit appears red while the petioles appear purple-red. Additionally, in the white-fruited diploid strawberries, the petioles can accumulate anthocyanins normally, suggesting a different synthesis pattern between the petioles and fruits. We screened the EMS mutagenized population of a red-fruited diploid strawberry 'Ruegen' and discovered a mutant which showed no anthocyanin accumulation in the petioles but normal accumulation in the fruit. Through BSA sequencing and allelic test, it was found that a mutation in FvDFR2 was responsible for this phenotype. Furthermore, the complex formed by the interaction between the petiole-specific FvMYB10L and FvTT8 only binds the promoter of FvDFR2 but not FvDFR1 , resulting in the expression of only FvDFR2 in the petiole. FvDFR2 can catalyze the conversion of DHQ and eventually the formation of cyanidin and peonidin, giving the petiole a purplish-red color. In the fruit, however, both FvDFR1 and FvDFR2 can be expressed, which can mediate the synthesis of cyanidin and pelargonidin. Our study clearly reveals different regulation of FvDFR1 and FvDFR2 in mediating anthocyanin synthesis in petioles and fruits. • Mutations in FvDFR2 result in a phenotype of green petiole in strawberry. • In petioles, only FvDFR2 expressed while both FvDFR1 and FvDFR2 expressed in fruits. • FvMYB10L and FvTT8 selectively binds to the FvDFR2 promoter instead of FvDFR1. • FvDFR1 compensates for the loss of FvDFR2 function in forming cyanidin in fruits. [ABSTRACT FROM AUTHOR]

The characterization of straw decomposition and the resulting carbon (C) and nitrogen (N) release is crucial for understanding the effects of different straw returning methods on the immobilization and cycling of soil organic carbon (SOC) and soil total nitrogen (STN). In 2017–2018, a field micro-plot experiment was carried out in northeastern China to investigate the effects of different straw returning approaches on straw decomposition, C release, N release, SOC, STN, and the soil C–N ratio. Six straw returning treatments were applied: straw mixed with soil (SM) and straw buried in the soil (SB) at soil depths of 10 (O), 30 (T), and 50 cm (F). The results indicate that the straw decomposition proportion (SD), C release, and N release in SM + O were higher than that in SM + T and SM + F. Moreover, SOC and STN concentrations and the soil C–N ratio were significantly enhanced by SM/B + O in the 0–20 cm soil layers, SM/B + T in the 20–30 cm soil layer, and SM/B + F in the 40–60 cm soil layers. In the 0–50 cm soil profile, the highest SOC stocks were obtained using SB + T. The STN stocks were also significantly affected by the straw returning depth, but the effect was inconsistent between the two years. SD had a positive relationship with SOC and STN in the 0–20 cm soil layers; conversely, they were negatively related in the 30–60 cm soil layers. The results of this study suggest that straw buried in the soil to a depth not exceeding 30 cm might be an optimal straw returning approach in northeastern China. [ABSTRACT FROM AUTHOR]

Light is an important environmental factor, which mainly inhibits hypocotyl elongation through various photoreceptors. In contrast, brassinosteroids (BRs) are major hypocotyl elongation-promoting hormones in plants, which could optimize photomorphogenesis concurrent with external light. However, the precise molecular mechanisms underlying the antagonism of light and BR signaling remain largely unknown. Here we show that the Arabidopsis red light receptor phyB is involved in inhibition of BR signaling via its direct interaction with the BR transcription factor BES1. In our study, the phyB mutant displays BR hypersensitivity, which is repressed in transgenic plants overexpressing phyB, suggesting that phyB negatively regulates the BR signaling pathway. In addition, protein interaction results show that phyB directly interacts with dephosphorylated BES1, the physiologically active form of BES1 induced by BR, in a red light-dependent manner. Genetic analyses suggest that phyB may act partially through BES1 to regulate BR signaling. Transcriptomic data and quantitative real-time PCR assay further show that phyB-mediated red light inhibits BR signaling by repressing expression of BES1 target genes, including the BR biosynthesis genes DWF4, the SAUR family and the PRE family genes required for promoting cell elongation. Finally, we found that red light treatment inhibits the DNA-binding activity of BES1 and photoactivated phyB represses the transcriptional activity of BES1 under red light. Taken together, we suggest that the interaction of phyB with dephosphorylated BES1 may allow plants to balance light and BR signaling by repressing transcriptional activity of BES1 to regulate expression of its target genes. [ABSTRACT FROM AUTHOR]

Cryptochromes (CRYs) are blue light photoreceptors that mediate a variety of light responses in plants and animals, including photomorphogenesis, flowering, and circadian rhythms. The signaling mechanism by which Arabidopsis thaliana cryptochromes CRY1 and CRY2 promote photomorphogenesis involves direct interactions with COP1, a RING motif-containing E3 ubiquitin ligase, and its enhancer SPA1. Brassinosteroid (BR) is a key phytohormone involved in the repression of photomorphogenesis, and here, we show that the signaling mechanism of Arabidopsis CRY1 involves the inhibition of BR signaling. CRY1 and CRY2 physically interact with BES1-INTERACTING MYC-LIKE1 (BIM1), a basic helix-loop-helix protein. BIM1, in turn, interacts with and enhances the activity of BRI1-EMS SUPPRESSOR1 (BES1), a master transcription factor in the BR signaling pathway. In addition, CRY1 and CRY2 interact specifically with dephosphorylated BES1, the physiologically active form of BES1 that is activated by BR in a blue light-dependent manner. The CRY1-BES1 interaction leads to both the inhibition of BES1 DNA binding activity and the repression of its target gene expression. Our study suggests that the blue light-dependent, BR-induced interaction of CRY1 with BES1 is a tightly regulated mechanism by which plants optimize photomorphogenesis according to the availability of external light and internal BR signals. [ABSTRACT FROM AUTHOR]

Cryptochromes (CRYs) are blue light photoreceptors that mediate various light responses in plants and animals. In Arabidopsis, there are two homologous CRYs, CRY1 and CRY2, which mediate blue light inhibition of hypocotyl elongation. It is known that CRY2 interacts with CIB1, a basic helix–loop–helix (bHLH) transcriptional factor, to regulate transcription and floral induction. In this study, we performed yeast two-hybrid screening and identified CIB1 as a CRY1-interacting protein. Moreover, we demonstrated that CRY1 physically interacted with the close homolog of CIB1, HBI1, which is known to act downstream of brassinosteroid (BR) and gibberellin acid (GA) signaling pathways to promote hypocotyl elongation, in a blue light-dependent manner. Transgenic and genetic interaction studies showed that overexpression of HBI1 resulted in enhanced hypocotyl elongation under blue light and that HBI1 acted downstream of CRYs to promote hypocotyl elongation. Genome-wide gene expression analysis indicated that CRYs and HBI1 antagonistically regulated the expression of genes involved in regulating cell elongation. Moreover, we demonstrated that CRY1–HBI1 interaction led to inhibition of HBI1’s DNA binding activity and its target gene expression. Together, our results suggest that HBI1 acts as a new CRY1-interacting protein and that the signaling mechanism of CRY1 involves repression of HBI1 transcriptional activity by direct CRY1–HBI1 interaction. [ABSTRACT FROM AUTHOR]

Light is a key environmental cue that inhibits hypocotyl cell elongation through the blue and red/far-red light photoreceptors cryptochrome- and phytochrome-mediated pathways in Arabidopsis . In contrast, as a pivotal endogenous phytohormone auxin promotes hypocotyl elongation through the auxin receptors TIR1/AFBs-mediated degradation of AUX/IAA proteins (AUX/IAAs). However, the molecular mechanisms underlying the antagonistic interaction of light and auxin signaling remain unclear. Here, we report that light inhibits auxin signaling through stabilization of AUX/IAAs by blue and red light-dependent interactions of cryptochrome 1 (CRY1) and phytochrome B with AUX/IAAs, respectively. Blue light-triggered interactions of CRY1 with AUX/IAAs inhibit the associations of TIR1 with AUX/IAAs, leading to the repression of auxin-induced degradation of these proteins. Our results indicate that photoreceptors share AUX/IAAs with auxin receptors as the same direct downstream signaling components. We propose that antagonistic regulation of AUX/IAA protein stability by photoreceptors and auxin receptors allows plants to balance light and auxin signals to optimize their growth. [ABSTRACT FROM AUTHOR]

Key message: Using map-based cloning of ts gene, we identified a new sort of gene involved in the initiation of multicellular tender spine in cucumber. Abstract: The cucumber ( Cucumis sativus L.) fruit contains spines on the surface, which is an extremely valuable quality trait affecting the selection of customers. In this study, we elaborated cucumber line NC072 with wild type (WT) hard fruit spines and its spontaneous mutant NC073, possessing tender and soft spines on fruits. The mutant trait was named as tender spines ( ts), which is controlled by a single recessive nuclear gene. We identified the gene ts by map-based cloning with an F segregating population of 721 individuals generated from NC073 and WT line SA419-2. It was located between two markers Indel6239679 and Indel6349344, 109.7 kb physical distance on chromosome 1 containing fifteen putative genes. With sequencing and quantitative reverse transcription-polymerase chain reaction analysis, the Csa1G056960 gene was considered as the most possible candidate gene of ts. In the mutant, Csa1G056960 has a nucleotide change in the 5′ splicing site of the second intron, which causes different splicing to delete the second exon, resulting in a N-terminal deletion in the predicted amino acid sequence. The gene encodes a C-type lectin receptor-like tyrosine-protein kinase which would play an important role in the formation of cucumber fruit. This is firstly reported of a receptor kinase gene regulating the development of multicellular spines/trichomes in plants. The ts allele could accelerate the molecular breeding of cucumber soft spines. [ABSTRACT FROM AUTHOR]

• Mutation-FvMYB10 abolished to biosynthesize anthocyanin in Arabidopsis and strawberry. • FvMYB10 localized as speckles, while FvmMYB10 was not. • FvMYB10 directly bound and activated the expression of FvCHS2 and FvDFR1. • FvmMYB10 failed to bind and activate the expression of FvCHS2 and FvDFR1. FvMYB10 protein has been proved to be a transcriptional switch for anthocyanin biosynthesis in strawberry. A single nucleotide mutation in R2 domain of FvMYB10, named as FvmMYB10, is found to be responsible for the white color in strawberry variety 'Yellow Wonder'. However, the mechanism of FvmMYB10 suppresses anthocyanin biosynthesis in strawberry is largely unknown. Here, we show that the transcriptional level of FvMYB10 and key enzyme genes involved in anthocyanin biosynthesis in 'Yellow Wonder' were lower than that in red color variety 'Ruegen', especially at turning to ripening stage. The low expression level of FvmMYB10 may due to his inability to bind to its promoter region and activate its own expression. We found FvMYB10- overexpressing, but not FvmMYB10 -overexpressing, promote anthocyanin accumulation in Arabidopsis and strawberry fruit despite of their similar expression levels. In addition, subcellular localization assay indicated that FvMYB10-YFP, but not FvmMYB10-YFP, localized to sub-nucleus foci (speckles) in the nucleus, implying the mutation of FvMYB10 might inhibit its transcription factor activity and eventually interfere with its function. Subsequently, we confirmed that FvMYB10 bind to the promoter region of some specific key enzyme genes, including FvCHS2 and FvDFR1 and activated their expression. While FvmMYB10 failed to binding and transcriptional activating these genes. Our findings provide insights into molecular mechanism of anthocyanin biosynthesis regulated by MYB10 in strawberry fruits. [ABSTRACT FROM AUTHOR]

Background: Pedicel orientation can affect the female flower orientation and seed yield in cucumber. A spontaneous mutant possessing upward growth of pedicels was identified in the wild type inbred strain 9930 and named upward-pedicel (up). The morphological and genetic analyses of up were performed in this study. In order to clone the up gene, 933 F2 individuals and 524 BC1 individuals derived from C-8-6 (WT) and up were used for map-based cloning. Results: up was mapped to a 35.2 kb physical interval on chromosome 1, which contains three predicted genes. Sequencing analysis revealed that a 5-bp deletion was found in the second exon of Csa1G535800, and it led to a frameshift mutation resulting in a premature stop codon. The candidate gene of CsUp (Csa1G535800) was further confirmed via genomic and cDNA sequencing in biparental and natural cucumber populations. Sequencing data showed that a 4-bp deletion was found in the sixth exon of Csa1G535800 in CGN19839, another inbred line, and there was also a mutation of an amino acid in Csa1G535800 that could contribute to the upward growth of pedicels in CGN19839. Moreover, it was found that Csa1G535800 exhibited strong expression in the pedicel of WT, suggesting its important role in development of pedicel orientation. Thus, Csa1G535800 was considered to be the candidate gene of CsUp. Conclusions: CsUp encodes an Auxilin-like protein and controls pedicel orientation in cucumber. The identification of CsUp may help us to understand the mechanism of pedicel orientation development and allow for investigation of novel functions of Auxilin-like proteins in cucumber. [ABSTRACT FROM AUTHOR]