查看更多>>摘要：N and Ca are essential nutrients for apple growth and development.Studies have found that Ca content was not low under high N conditions but was poorly available.However,the underlying physiological mechanism through which N regulates Ca availability remains unclear.In this study,apple plants were supplied with N and Ca to analyse the content,in situ distribution,and forms of Ca using noninvasive micro-test technique,electron probe microanalysis,Fourier transform infrared spectroscopy,and transcriptome analysis.A potential interaction was observed between N and Ca in apple leaves.The application of high N and Ca concentration led to a CaOx content of 12.51 g/kg,representing 93.54％of the total Ca in the apple leaves.Electron probe microanalysis revealed that Ca deposited in the phloem primarily existed as CaOx rhombus-shaped crystals.Additionally,high N positively regulated oxalate accumulation in the leaves,increasing it by 40.79 times compared with low N concentration.Specifically,N induced oxalate synthesis in apple leaves by upregulating the MdICL,MdOXAC,and MdMDH genes,while simultaneously inhibiting degradation through downregulation of the MdAAE3 gene.Transcriptome and correlation analyses further confirmed oxaloacetate as the precursor for the synthesis of CaOx crystals in the apple leaves,which were produced via the'photosynthesis/glycolysis-oxaloacetate-oxalate-CaOx'pathway.WGCNA identified potential regulators of the CaOx biosynthesis pathway triggered by N.Overall,the results provide insights into the regulation of Ca availability by N in apple leaves and support the development of Ca efficient cultivation technique.
查看更多>>摘要：Lily(Lilium spp.),a horticultural crop serving both ornamental and edible functions,derives its coloration primarily from anthocyanins.However,limited studies have been conducted on the accumulation of anthocyanins within lilies.In this study,we cloned a light-induced transcription factor named as LvBBX24 in lilies.Through genetic and biochemical analysis,we determined that LvBBX24 could upregulate the transcription of LvMYB5 and facilitate anthocyanin synthesis.Moreover,we identified that darkness promoted the degradation of LvBBX24 protein.Through screening a yeast library,we identified LvbZIP44 acts as its interacting partner.Genetic testing confirmed that LvbZIP44 also plays a role in promoting lily anthocyanin synthesis.This indicates a potential synergistic regulatory effect between LvBBX24 and LvbZIP44.Our study indicates that LvBBX24 and LvbZIP44 cooperate to regulate anthocyanin accumulation in lily petals.These findings provide compelling evidence supporting the idea that LvBBX24 and LvbZIP44 may form a looped helix surrounding the LvMYB5 promoter region to regulate anthocyanin biosynthesis.
查看更多>>摘要：Anthocyanins are important compounds for fruit quality and nutrition.The R2R3 MYB transcription factor PpMYB10.1 is known to be critical for regulating anthocyanin accumulation in peach.However,regulatory factors upstream of PpMYB10.1 which control temperature-dependent,cultivar-contrasted and tissue-specific anthocyanin accumulation remain to be determined.In this study,differential anthocyanin accumulation in the outer flesh near the peel(OF)of peach[Prunus persica(L.)Batsch]was observed between cultivars'Zhonghuashoutao'and'Dongxuemi',as well as among different storage temperatures and different fruit tissues of'Zhonghuashoutao'.By cross-comparisons of RNA-Seq data of samples with differential anthocyanin accumulation,transcription factor genes PpBBX32 and PpZAT5 were identified.These were functionally characterized as two positive regulators for anthocyanin accumulation via transient expression and genetic transformation.Various interaction assays revealed that both PpBBX32 and PpZAT5 can directly activate the PpMYB10.1 promoter and meanwhile interact at protein level as a PpZAT5-PpBBX32-PpMYB10.1 complex.Furthermore,the results of in silico analysis and exogenous application of methyl jasmonate(MeJA)indicated that MeJA favored anthocyanin accumulation,while it was also found that anthocyanin accumulation as well as PpBBX32 and PpZAT5 expression correlated significantly with endogenous JA and JA-Ile in different fruit tissues.In summary,PpBBX32 and PpZAT5 are upstream activators of PpMYB10.1,allowing JAs to take part in temperature-dependent and tissue-specific anthocyanin accumulation by modulating their expression.This work enriches the knowledge of the transcriptional regulatory mechanisms for differential anthocyanin accumulation under internal and external factors.
查看更多>>摘要：Developing disease-suppressive soils is an effective approach for managing soilborne diseases,which can be achieved through crop metabolism and root secretion modification to recruit beneficial soil microbiota.Many factors,such as light,can elicit and modify plant metabolomic activities,resulting in disease suppression.To investigate the impact of light,Panax notoginseng was planted in a greenhouse and forest,conditioned with three levels of light intensities,including the optimal(15％light transmittance of full light),suboptimal low(5％light transmittance of full light)and suboptimal high(30％light transmittance of full light)intensities.We assessed the rhizosphere microbiota of P.notoginseng and root rot disease caused by soilborne pathogen Ilyonectria destructans,and elucidated the mechanism.Results showed that suboptimal light conditions alleviated root rot disease of P.notoginseng by enriching beneficial microbiota in the rhizosphere.Both low and high light stresses enhanced the secondary metabolism profile in favor of plant defense,particularly the flavonoid pathway.Notably,high light stress demonstrated a robust ability to promote flavonoid metabolism and secretion,resulting in the enrichment of more beneficial microorganisms that suppressed the soilborne pathogen I.destructans.These findings highlight the potential for adjusting canopy light intensities to improve soil health and promote sustainable agriculture.
查看更多>>摘要：In Chinese cabbage development the interplay between shoot apex activity and vernalization is pivotal for flowering timing.The intricate relationship between various cell types in the shoot apex meristem and their roles in regulating flowering gene expression in Chinese cabbage is not yet fully understood.A thorough analysis of single-cell types in the Chinese cabbage shoot apex and their influence on flowering genes and vernalization is essential for deeper insight.Our study first established a single-cell transcriptomic atlas of Chinese cabbage after 25 days of non-vernalization.Analyzing 19602 single cells,we differentiated them into 15 distinct cell clusters using established marker genes.We found that key genes in shoot apex development and flowering were primarily present in shoot meristematic cells(SMCs),companion cells(CCs),and mesophyll cells(MCs).MADS-box protein FLOWERING LOCUS C 2(BrFLC2),a gene suppressing flowering,was observed in CCs,mirroring patterns found in Arabidopsis.By mapping developmental trajectories of SMCs,CCs,and MCs,we elucidated the evolutionary pathways of crucial genes in shoot apex development and flowering.The creation of a single-cell transcriptional atlas of the Chinese cabbage shoot apex under vernalization revealed distinct alterations in the expression of known flowering genes,such as VERNALIZATION INSENSITIVE 3(VIN3),VERNALIZATION 1(VRN1),VERNALIZATION 2(VRN2),BrFLC,and FLOWERING LOCUS T(FT),which varied by cell type.Our study underscores the transformative impact of single-cell RNA sequencing(scRNA-seq)for unraveling the complex differentiation and vernalization processes in the Chinese cabbage shoot apex.These insights are pivotal for enhancing breeding strategies and cultivation management of this vital vegetable.
查看更多>>摘要：Fruit aroma is an important organoleptic quality,which influences consumer preference and market competitiveness.Aroma compound synthesis pathways in plants have been widely identified,among the lipoxygenase pathway is crucial for fatty acid catabolism to form esters in apple.However,the regulatory mechanism of this pathway remains elusive.In this study,linear regression analysis and transgene verification revealed that the lipoxygenase MdLOX1a is involved in ester biosynthesis.Yeast one-hybrid library screening indicated that a protein,MdASG1(ABIOTIC STRESS GENE 1),was a positive regulator of MdLOX1a and ester production based on yeast one-hybrid and dual-luciferase assays,as well as correlation analysis among eight different apple cultivars.Overexpression of MdASG1 in apple and tomato stimulated the lipoxygenase pathway and increased the fatty acid-derived volatile content,whereas the latter was decreased by MdASG1 silencing and CRISPR/Cas9 knockout.Furthermore,MdASG1 overexpression enhanced the salt-stress tolerance of tomato and apple'Orin'calli accompanied by a higher content of fatty acid-derived volatiles compared to that of non-stressed transgenic tomato fruit,while MdASG1-Cas9 knockdown calli do not respond to salt stress and promote the biosynthesis of fatty acid-derived volatiles.Collectively,these findings indicate that MdASG1 activates MdLOX1a expression and participates in the lipoxygenase pathway,subsequently increasing the accumulation of aroma compounds,especially under moderate salt stress treatment.The results also provide insight into the theory for improving fruit aroma quality in adversity.
查看更多>>摘要：Orphan genes(OGs)are unique to the specific species or lineage,and whose homologous sequences cannot be found in other species or lineages.Furthermore,these genes lack recognizable domains or functional motifs,which make their characterization difficult.Here,we identified a Brassica rapa OG named BOLTING RESISTANCE 2(BR2)that could positively modulate bolting resistance.The expression of BR2 was developmentally regulated and the BR2 protein was localized to the cell membrane.BR2 overexpression not only markedly delayed flowering time in Arabidopsis transgenic plants,but substantially affected the development of leaves and flower organs.Flowering repressor AtFLC gene was significantly up-regulated transcribed in Arabidopsis BR2 overexpression lines,while AtFT and AtSOC1 expression was decreased.In addition,the BR2 expression was enhanced in bolting-resistant type Chinese cabbage and was reduced in non-resistant type.Moreover,chilling stress inhibited the BR2 expression levels.Overexpression of BR2 also delayed flowering time in Chinese cabbage.In vernalized Chinese cabbage BR2 overexpression plants,BrVIN3.b and BrFRI were significantly down-regulated,while BrFLC5 was substantially up-regulated.Key floral factors,including three BrSOC1s,two BrLFYs,and four BrFTs were down-regulated.The expression changes of these key genes were consistent with the delayed flowering phenotype of Chinese cabbage BR2 overexpressing plants.Thus,we predicted that BR2 may predominantly function via the vernalization pathway.Our findings propose that the OG BR2 acts as a novel modulator of flowering time in Chinese cabbage,which provides a new insight on the breeding of varieties that are resistant to bolting.
查看更多>>摘要：Tea seedlings(Camellia sinensis)have a well-developed root system with a strong taproot and lateral roots.Compared with ordinary cuttings,tea has stronger vitality and environmental adaptability,thus facilitating the promotion of good varieties.However,there is less of detailed research on the rooting and germination process of tea seeds.In this study,matrix-assisted laser desorption ionization time-of-flight-mass spectrometry was used to conduct non-targeted spatial mass spectrometry imaging of the main organs during growth of tea seedlings.A total of 1234 compounds were identified,which could be divided into 24 classes.Among them,theanine,as the most prominent nitrogen compound,was synthesized rapidly at the early stage of embryo germination,accounting for＞90％of the total free amino acids in the radicle,and it was then transferred to each meristem region through the mesocolumnar sheath,indicating that theanine-based nitrogen flow plays a decisive role in organ formation during the development of tea seedlings.Nutrients stored in the cotyledon were rapidly hydrolyzed to dextrin and 3-phosphoglyceraldehyde at the early stages of germination,and subsequently converted to other forms that provided carbon and energy for development,such as raffinose and D-galactose(glucose),which were mainly distributed in the growing zones of the root apex and the apical meristems of the stem.This study provides a new perspective on the synthesis and metabolism of substances during the development of tea seedlings and contributes to a better understanding of the biological characteristics of tea varieties.
查看更多>>摘要：Cold temperatures negatively impact crop yield and quality,posing significant limitations to the advancement of the vegetable industry.MYB transcription factors are pivotal in enhancing plant resilience against various abiotic stresses,including low-temperature stress.Pepper(Capsicum annuum L.)is a nutrient-rich vegetable crop sensitive to low temperatures.This study aimed to determine the function of CaMYB80 in the cold stress response of pepper through virus-induced silencing.The study also conducted heterologous expression of CaMYB80 in Arabidopsis and tomato plants.The results showed that CaMYB80 could respond to low-temperature stress in pepper.CaMYB80 was localized in the nucleus and cytoplasm and exhibited transcriptional activation ability.Moreover,CaMYB80 silencing decreased cold tolerance in pepper,while its heterologous overexpression increased cold tolerance in Arabidopsis and tomato.Further analysis showed that CaMYB80 interacted with CaPOA1(peroxidase N1-like).Similarly,the expression of CaPOA1 also responded to low-temperature stress.Overexpression of CaPOA1 enhanced freezing tolerance in Arabidopsis,while its silencing reduced cold stress tolerance in pepper.Furthermore,overexpression of CaMYB80 in Arabidopsis and tomato could increase the activity of peroxidases and the expression levels of genes in the ICE-CBF-COR(inducer of CBF expression,C-repeat binding factor,cold-responsive)regulatory network.In conclusion,our research results indicate that CaMYB80 enhances pepper cold tolerance by interacting with CaPOA1 to increase peroxidase activity and influence the expression of ICE-CBF-COR related genes.
查看更多>>摘要：Land plants are well-known producers of terpenoids that play diverse roles in plant-environment interactions.The vast chemical diversity of terpenoids is initiated by terpene synthases.Plants contain a distinct mid-sized terpene synthase gene family termed TPS,which appears to have an ancient origin in a fused bacterial Class I(di)terpene synthase(TS)and Class Ⅱ diterpene cyclase(DTC),corresponding to the catalytically relevant α-domain and βγ-didomains,respectively.However,while such fused tridomain bifunctional(Class Ⅰ/Ⅱ)diterpene cyclases/synthases(DCSs)have been found in plants(and fungi),no examples have been reported from bacteria,leaving the origin of the fusion event initiating the TPS gene family opaque.Here,the discovery of such tridomain bifunctional DCSs in bacteria is reported.Extensive genome mining unearthed five putative bacterial DCSs,with biochemical characterization revealing the expected bifunctional activity for three.The most intriguing was CseDCS from Candidatus sericytochromatia bacterium,which produces ent-kaurene,an intermediate in plant hormone biosynthesis,as this is the hypothesized activity for the ancestral TPS.Unlike the extant functionally equivalent TPSs,it was possible to split CseDCS into separate,independently acting DTC and TS,with the first producing the expected ent-copalyl diphosphate(CPP),serving as a CPP synthase(CPS),while the second converts this to ent-kaurene,serving as a kaurene synthase(KS).Nevertheless,sequence alignment and mutation analysis revealed intriguing similarities between this cyanobacterial fused CPS-KS and functionally equivalent TPSs.Regardless of the exact relationship,the discovery of fused bifunctional DCSs in bacteria supports the hypothesized origin of the plant TPS family from such a bacterial gene.
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