Effects of Heterologously Overexpressing PIP5K-Family Genes in Arabidopsis on Inflorescence Development

Castor is one of the top 10 oil crops in the world and has extremely valuable uses.Castor inflorescences directly affect yield,so the study of inflorescence development is very important in increasing castor yield.Our previous studies have shown that the PIP5K gene family(PIP5Ks)is associated with inflorescence development.In this study,to determine the function of each PIP5K gene in castor,a female Lm-type castor line,aLmAB2,was used to determine the relative expression levels of the PIP5Ks in castor inflorescences.Six PIP5K genes were heterologously overexpressed in Arabidopsis thaliana,the relative expression of each gene and the effect on plants was determined in A.thaliana,and the relationships among the PIP5Ks in castor were inferred.The expression levels of the PIP5Ks in the female Lm-type castor line aLmAB2 were analyzed.The relative expression levels of the PIP5K9 and PIP5K11 genes were high(p<0.05)in isofemale inflorescences,and those of PIP5K1,PIP5K2,PIP5K6,and PIP5K8 were high(p<0.05)in female inflorescences but low(p<0.05)in bisexual inflorescences.The PIP5Ks were heterologously overexpressed in A.thaliana,and T3-generation plants with stable genetic resistance,i.e.,AT-PIP5K^(+)plants(AT-PIP5K1^(+),AT-PIP5K2^(+),AT-PIP5K6^(+),AT-PIP5K8^(+),AT-PIP5K9^(+),and ATPIP5K11^(+) plants),were obtained.Biological tests of the AT-PIP5K+plants showed that the growth of the main stem was significantly delayed in AT-PIP5K+plants compared with Columbia wild-type(WT)A.thaliana plants;the PIP5K1 and PIP5K2 genes promoted lateral stem growth and flower and silique development;and the PIP5K6,PIP5K8,PIP5K9 and PIP5K11 genes inhibited lateral stem growth and flower and silique development.The correlations among PIP5Ks in castor suggest that there may be a synergistic relationship among PIP5K1,PIP5K2,and PIP5K6 in castor inflorescences,and PIP5K8,PIP5K9,and PIP5K11 are complementary to the other three genes.

Transcriptome Analysis of Inflorescence Development at the Five-Leaf Stage in Castor(Ricinus communis L.)

The yield of castor is influenced by the type of inflorescence and the proportion of female flowers.However,there are few studies on the genetic mechanism involved in the development and differentiation of castor inflorescences.In this study,we performed transcriptomic analyses of three different phenotypes of inflorescences at the five-leaf stage.In comparison to the MI(complete pistil without willow leaves),290 and 89 differentially expressed genes(DEGs)were found in the SFI(complete pistil with willow leaves)and the BI(monoecious inflorescence),respectively.Among the DEGs,104 and 88 were upregulated in the SFI and BI,respectively,compared to the MI.In addition,186 DEGs and 1 DEG were downregulated in the SFI and BI compared to the MI.Moreover,we conducted GO and KEGG enrichment analyses of the DEGs.In comparison to the MI,the SFI and BI exhibited the enrichment of functional branches in DEGs,specifically in pollen wall assembly,pollen development,and cellular component assembly involved in morphogenesis.In our study,RADL5 showed low expression levels between SFI-vs.-MI types.In addition,we found that the expression of NAC in the SFI differed from that in MI and BI,and some genes related to hormonal signaling changed their expression levels during inflorescence differentiation.These results reveal the genetic mechanism of sex genotypes in castor,which will not only guide researchers in the breeding of castor but also provide a reference for genetic research on other flowering plants.

Molecular phylogeny and inflorescence evolution of Prunus(Rosaceae)based on RAD-seq and genome skimming analyses

Prunus is an economically important genus widely distributed in the temperate Northern Hemisphere.Previous studies on the genus using a variety of loci yielded conflicting phylogenetic hypotheses.Here,we generated nuclear reduced representation sequencing data and plastid genomes for 36 Prunus individuals and two outgroups.Both nuclear and plastome data recovered a well-resolved phylogeny.The species were divided into three main clades corresponding to their inflorescence types,-the racemose group,the solitary-flower group and the corymbose group-with the latter two sister to one another.Prunus was inferred to have diversified initially in the Late Cretaceous around 67.32 million years ago.The diversification of the three major clades began between the Paleocene and Miocene,suggesting that paleoclimatic events were an important driving force for Prunus diversification.Ancestral state reconstructions revealed that the most recent common ancestor of Prunus had racemose inflorescences,and the solitary-flower and corymb inflorescence types were derived by reduction of flower number and suppression of the rachis,respectively.We also tested the hybrid origin hypothesis of the racemose group proposed in previous studies.Prunus has undergone extensive hybridization events,although it is difficult to identify conclusively specific instances of hybridization when using SNP data,especially deep in the phylogeny.Our study provides well-resolved nuclear and plastid phylogenies of Prunus,reveals substantial cytonuclear discord at shallow scales,and sheds new light on inflorescence evolution in this economically important lineage.

Functional Studies of Castor(Ricinus communis L.)PLC Family Genes in Arabidopsis Inflorescence Development

Castor(Ricinus communis L.)is one of the top 10 oil crops in the world,and inflorescence is a trait that directly affects its yield.Phospholipase C(PLCs)is involved in many plant activities and metabolic processes.To study the functions of PLC family genes in the regulation of the inflorescence development of the female line of Lm-type castor aLmAB2,we determined the expression levels of six PLC family genes of three types of inflorescences of aLmAB2(isofemale line,female line,bisexual line)at different developmental stages.The results showed that the 6 genes of the castor PLC family had relative expression levels at different developmental stages of the three types of inflorescences.The subcellular location of all six protein products was the cell membrane.The six genes were heterologously overexpressed in Arabidopsis thaliana to obtain the T3 generation-resistant Arabidopsis thaliana plants.The results showed that the overexpression of six genes significantly promoted the maturation of Arabidopsis thaliana,the growth of lateral moss,and the development of flowers and pods,but the development of basal leaves and stem leaves of Arabidopsis thaliana was significantly inhibited.According to homology analysis,it is speculated that PLC2,PLC2M,PLC2N,PLC4,PLC4X2,and PLC6 genes have the same regulatory function.

Constructing the maize inflorescence regulatory network by using efficient tsCUT&Tag assay

Maize ear development determines the crop yield,and many important transcription factors(TFs)have been identified to function in this process.However,their transcriptional regulation mechanisms are still elusive.In this study,we generated the genome-wide DNA binding sites for 8 TFs which are known to function or highly expressed in inflorescence by applying the ts CUT&Tag method in maize leaf protoplast.We exposed a regulatory grid of 4 WUSCHEL-related homeobox(WOX)genes and revealed their potential regulatory mechanisms.In addition,a hierarchical regulation network for the determinacy and specification of maize inflorescence meristems were also constructed using the binding profiles of a floral development gene INDETERMINATE FLORAL APEX1(IFA1)and 3 MADS-box genes.Our study provides an in-depth understanding and new insights of the regulatory mechanisms during maize inflorescence development.

Barley FASCIATED EAR genes determine inflorescence meristem size and yield traits

In flowering plants,the inflorescence meristem(IM)provides founder cells to form successive floral meristems,which are precursors of fruits and seeds.The activity and developmental progression of IM are thus critical for yield production in seed crops.In some cereals,such as rice(Oryza sativa)and maize(Zea mays),the size of undifferentiated IM,which is located at the inflorescence apex,is positively associated with yield traits such as spikelet number.However,the relationship between IM size and yieldrelated spike traits remains unknown in the Triticeae tribe.Here we report that IM size has a negative correlation with yield traits in barley(Hordeum vulgare).Three FASCIATED EAR(FEA)orthologs,HvFEA2,HvFEA3,and HvFEA4,regulate IM size and spike morphogenesis and ultimately affect yield traits.Three HvFEAs genes are highly expressed in developing spikes,and all three loss-of-function mutants exhibit enlarged IM size,shortened spikes,and reduced spikelet number,which may lead to reduced grain yield.Natural variations identified in HvFEAs indicate selection events during barley domestication.We further reveal that HvFEA4,as a transcription factor,potentially targets multiple pathways during reproductive development,including transcriptional control,phytohormone signaling,and redox status.The roles of barley FEA genes in limiting IM size and promoting spikelet formation suggest the potential of increasing yield by manipulating IM activity.

Proteomic Analyses of Three Inflorescence Styles of Castor(Ricinus communis L.)at Different Developmental Stages

Castor(Ricinus communis L.)is one of ten oil crops in the world and has complex inflorescence styles.Generally,castor has three inflorescence types:single female inflorescence(SiFF),standard female inflorescence(StFF)and bisexual inflorescence(BF).StFF is realized as a restorer line and as a maintainer line,which was applied to castor hybrid breeding.However,the developmental mechanism of the three inflorescences is not clear.Therefore,we used proteomic techniques to analyze different inflorescence styles.A total of 72 diferentially abundant protein species(DAPs)were detected.These DAPs are primarily involved in carbon and energy metabolism and carbon fixation in the photosynthetic organism pathway.The results showed that DAPs are involved in photosynthesis to control the distribution of imported carbohydrates and exported photoassimilates and thus affect the inflorescence development of castor.In addition,these DAPs are also involved in cysteine and methionine metabolism.Quantitative real-time PCR(qRT-PCR)results demonstrated that the proteomics data collected in this study were reliable.Our findings indicate that the carbon cycle and amino acid metabolism influence the inflorescence development of castor.

Growth and Development of Staminate Inflorescence and Anatomic Observation of Male Chestnut Flower

The growth and development of staminate inflorescence and anatomic structure of male chestnut flower were observed. Results showed that staminate in-florescence on the base of branch formed first, then upward successively. About 50 days were needed from the formation of staminate inflorescence on the base of branch to ful y develop the staminate inflorescence on the top of the branch. On the same staminate inflorescence, male flower clusters of the base formed first, then upward successively. About 20 days were needed from the formation of stami-nate inflorescence on the base of the male flower cluster to ful y develop the stami-nate inflorescence on the top of the branch. 5-7 male flowers forming a cluster, the flower number in a cluster was odd number usual y, and there was one on the top and each two paral el y arranged downward. The flower on the top came into bloom first, and then downward successively. The flowers paral el y arranged came into bloom at the same time. Sporangium of male flower of chestnut was monolocular. There were a large number of pol en grains in the sporangium. There were large differences between the development process of different sporangium in one male flower. Chestnut had larger quantity of male flowers and pol en and long period of pol ination compared with female flower. It is remained to be further studied whether it was necessary for anemophilous pol ination.

Direct Regeneration of Inflorescence from Callus in Dracaena fragrans cv. Massangeana Hort.

以花叶千年木 (Dracaenafragranscv .MassangeanaHort.)的花被筒、花序分枝轴和花序轴为外植体成功地诱导了花序的直接再生。3种外植体首先在MS附加 1.0mg L 6_BA和 0 .5_0 .8mg L 2 ,4_D的培养基上诱导形成愈伤组织 ,然后转移到MS附加 0 .5mg L 6_BA和 0 .0 0 5～ 0 .5mg L 2 ,4_D的培养基上分别诱导了花序的直接再生。

Diversity and Evolution of Inflorescences in Celastrales

Inflorescences structures in context of their evolution have been conducted for 60 genera and 170 species of Celastrales （according to APG （Angiosperm Phylogeny Group） III 2009, almost 60% of genera and 15% of species from this taxon of the world flora）. There are two big groups of inflorescences in Celastrales-intercalary （more often） and terminal. For many genera of Celastrales both types of inflorescences can be observed, although the frequency of their occurrence varies. There is an important difference between two types of inflorescences： character of completion of the main axis （the terminal flower present or absent）. Flower opening can be in basipetal （Celastraceae, Brexia） or acropetal （Stackhousiaceae） order. Partial inflorescence types included： simple, compound or umbrellate dichasia, spike, raceme, thyrse. Simple flowers of Parnassia are large, nested on long reproductive shoots, emerging from a rosette, with amplexicaule leaf.

Terminal Inflorescence and Restricted Branching Genes in Lupins （L. albus L., L. angustifolius L., L. luteus L.） and Field Bean （Vicia faba L.） Breeding in Poland

The objective of this paper is to present a new ideotype of grain legume cultivar and show improvements in breeding from the introduction of the terminal inflorescence （ti） gene in field bean, and the introduction of the restricted branching （rb） gene in three lupin crops--narrow-leafed lupin, white lupin and yellow lupin. Field trials using control cultivars were conducted at the Research Center for Cultivar Testing in Poland. For each species, different trial periods were selected in which new cultivars with ti/rb genes were registered. A breeding progress was estimated by a comparison of a new cultivar to control--bridge cultivar to the next trial period. Over the past twenty years cultivar improvement using ti/rb genes has proceeded differently in these species. The newest, self-completing legume cultivars have yields comparable to traditional ones and generally are earlier and more uniform when mature. This paper shows that breeding progress in rb yellow lupin is outstanding; in rb narrow-leafed lupin and ti field bean is favorable; and in rb white lupin is moderate.

Transcriptome profiling reveals phase-specific gene expression in the developing barley inflorescence

The shape of an inflorescence varies among cereals,ranging from a highly branched panicle in rice to a much more compact spike in barley(Hordeum vulgare L.)and wheat(Triticum aestivum L.).However,little is known about the molecular basis of cereal inflorescence architecture.We profiled transcriptomes at three developmental stages of the barley main shoot apex—spikelet initiation,floral organ differentiation,and floral organ growth—and compared them with those from vegetative seedling tissue.Transcript analyses identified 3688 genes differentially transcribed between the three meristem stages,with a further 1394 genes preferentially expressed in reproductive compared with vegetative tissue.Coexpression assembly and Gene Ontology analysis classified these 4888 genes into 28 clusters,revealing distinct patterns for genes such as transcription factors,histone modification,and cell-cycle progression specific for each stage of inflorescence development.We also compared expression patterns of VRS(SIX-ROWED SPIKE)genes and auxin-,gibberellic acid-and cytokinin-associated genes between two-rowed and six-rowed barley to describe regulators of lateral spikelet fertility.Our findings reveal barley inflorescence phase-specific gene expression,identify new candidate genes that regulate barley meristem activities and flower development,and provide a new genetic resource for further dissection of the molecular mechanisms of spike development.

Cytoprotective,antihyperglycemic and phytochemical properties of Cocos nucifera(L.) inflorescence

Objective:To analyze the eytoproteetive and antidiabetic activities as well as phytochemical composition of the immature inflorescence of Cocas nucifera belonging to the Arecaceae Family.Methods:The phytochemical screening of inflorescence was done to determine the major constituents present in Cocos nucifera inflorescence.The free radical scavenging potential of inflorescence extracts were evaluated using in vitro radical scavenging assay models.Results:The phytochemical analyses on inflorescence showed the presence of phenolic compounds,flavonoids.resins and alkaloids.The macronutrient analyses,on the other hand,showed the presence of carbohydrate,proteins and fibers.Administration of the methanol extract of coconut inflorescence to the diabetic rats showed dose dependent reduction in hyperglycemia.The cytoprotective property of coconut inflorescence was evidenced from the acute toxicological evaluation.The levels of serum aspartate aminotransferase,alanine aminotransferase,and alkaline phosphatase were significantly decreased in the diabetic rats treated with inflorescence when compared with the diabetic control rats.Conclusion:The results obtained from the present study apparently proved the non-toxic nature and the eytoproteetive and antihyperglycemic properties of coconut inflorescence.

Comparative transcriptomic analysis of Rosa sterilis inflorescence branches with different trichome types reveals an R3-MYB transcription factor that negatively regulates trichome formation

Rosa sterilis S.D.Shi is an important economic tree in China that produces fruits with high nutritional and medicinal value.Many of R.sterills’organs are covered with different types of trichomes or prickles that directly affect fruit appearance and plant management.This study used RNA sequencing technology to analyze the transcriptomes of two parts of the inflorescence branch,namely inflorescence stems with flagellated trichomes and pedicels with both flagellated and glandular trichomes.Comparative transcriptomic analysis showed that many transcription factors(TFs)are potentially involved in the formation and development of trichomes.The accumulation of RsETC1,a TF of the R3-MYB family,was significantly higher in inflorescence stems than in pedicels;quantitative reverse transcription PCR(qRTPCR)verified that its expression was significantly higher in inflorescence stems than in pedicels during the first three development stages,indicating its inhibitory action on the initiation of glandular trichomes in R.sterilis.The mRNA level of RsETC1 accumulated to significantly higher levels in trichomeless tissues than in tissues with trichromes,suggesting that this gene may inhibit the formation of trichomes in R.sterilis.Over-expression of RsETC1 in Arabidopsis resulted in glabrous phenotypes,and the expression of trichome-related endogenous genes,except for TTG1,was markedly reduced.In addition,the contents of the phytohormones jasmonic acid(JA),gibberellin A3(GA_(3)),and cytokinins(CKs)in pedicels were significantly higher than those in inflorescence stems,and the expression patterns of the genes related to hormone biosynthesis and signal transduction presented consistent responses,suggesting that the transduction of these hormones might be crucial for trichome initiation and development.These data provide a new perspective for revealing the molecular mechanism of trichome formation in R.sterilis.

Progressive meristem and single-cell transcriptomes reveal the regulatory mechanisms underlying maize inflorescence development and sex differentiation

Maize develops separate ear and tassel inflorescences with initially similar morphology but ultimately different architecture and sexuality.The detailed regulatory mechanisms underlying these changes still remain largely unclear.In this study,through analyzing the time-course meristem transcriptomes and floret single-cell transcriptomes of ear and tassel,we revealed the regulatory dynamics and pathways underlying inflorescence development and sex differentiation.We identified 16 diverse gene clusters with differential spatiotemporal expression patterns and revealed biased regulation of redox,programmed cell death,and hormone signals during meristem differentiation between ear and tassel.Notably,based on their dynamic expression patterns,we revealed the roles of two RNA-binding proteins in regulating inflorescence meristem activity and axillary meristem formation.Moreover,using the transcriptional profiles of 53910 single cells,we uncovered the cellular heterogeneity between ear and tassel florets.We found that multiple signals associatedwith either enhancedcell death or reduced growth are responsiblefortassel pistil suppression,while part of the gibberellic acid signal may act non-cell-autonomously to regulate ear stamen arrest during sex differentiation.We further showed that the pistil-protection gene SILKLESS 1(SK1)functions antagonistically to the known pistil-suppression genes through regulating common molecular pathways,and constructed a regulatory network for pistil-fate determination.Collectively,our study provides a deep understanding of the regulatory mechanisms underlying inflorescence development and sex differentiation in maize,laying the foundation for identifying new regulators and pathways for maize hybrid breeding and improvement.

Isolation and identification of genes expressed differentially in rice inflorescence meristem with suppression subtractive hybridization

A subtracted cDNA library of rice (Oryza sativa L.) inflorescence meristem (IM) was constructed using the suppression subtractive hybridization (SSH) method. The cDNAs of the rice shoot apical meristem (SAM) were used as 'driver' and inflorescence meristem (IM) as 'tester' in the experiment, respectively. Forty of 250 randomly chosen cDNA clones were identified by differential screening, which were IM-specific or IM-highly expressed. Most of the rice IM cDNAs cloned by SSH appear to represent rare transcripts, 40% of which were derived from truly differentially expressed genes. Of all the forty sequenced cDNA inserts, eleven contain the regions with 60%-90% identity to their homolog in GenBank, eighteen are expected to be new genes, only two correspond to published rice genes.

Plasticity of floral sex allocation within inflorescences of hermaphrodite Aconitum gymnandrum

Aims sex allocation in plants is often plastic,enabling individuals to adjust to variable environments.However,the predicted male-biased sex allocation in response to low resource conditions has rarely been experimentally tested in hermaphroditic plants.in particular,it is unknown whether distal flowers in linear inflorescences show a larger shift to male allocation relative to basal flowers when resources are reduced.in this study,we measure position-depend-ent plasticity of floral sex allocation within racemes of Aconitum gymnandrum in response to reduced resource availability.Methods using a defoliation treatment in the field applied to potted plants from a nested half-sibling design,we examined the effects of the treatment,flower position,family and their interactions.Important Findingsallocation to male function increased with more distal flower posi-tion,while female allocation either did not change with position or declined at the most distal flowers.Defoliation significantly reduced the mass of both the androecium and gynoecium,but not anther number or carpel number.gynoecial mass declined more strongly with defoliation than did androecial mass,resulting in a significant increase in the androecium/gynoecium ratio as predicted by sex allocation theory.Plastic responses of androecium mass and gynoecium mass were affected by flower position,with less mass lost in basal flowers,but similar plastic magnitude in both sexual traits across flower position lead to consistent variation in the androecium/gynoecium ratio along the inflorescence.a sig-nificant treatment*paternal family interaction for the androecium/gynoecium ratio is evidence for additive genetic variation for plastic floral sex allocation,which means that further evolution of alloca-tion can occur.

Floral sex allocation and reproductive success within inflorescences of Hosta ventricosa, a pseudogamous apomict

Aims Within inflorescences of sexually reproducing hermaphrodites,the production of ovules,fruits and seeds commonly declines from basal(early-opening)to distal(late-opening)flowers,while pol-len production remains constant or only changes slightly,with the result that distal(late-opening)flowers become functionally male.However,few empirical studies have specifically examined whether or not changes in allocation to pollen production actually lead to changes in the number of seeds sired,a more direct measure of male fitness.in pseudogamous apomicts,fitness depends on the number of seeds produced;thus,a contrasting pattern of variation in the pollen-to-ovule(P/o)ratio within inflorescences might be expected.Methods We investigated floral sex allocation and reproductive success within racemes of Hosta ventricosa,a pseudogamous apomictic hermaphrodite possessing flowers that open acropetally.We quan-tified variations in pollen number,ovule number,the P/o ratio and fruit and seed production,from 2007 to 2011,among flowers within racemes of four populations of H.ventricosa in southwest China.Ecological causes for fruit and seed production were evaluated by observing patterns of pollen deposition,flower removal and sup-plemental pollination.Important Findings Pollen number,ovule number and the P/o ratio declined from basal-to-distal positions in all sampled populations(years).Fruit and seed production decreased distally in most populations(years).low fruit and seed set of distal flowers was not due to pollen limitation because pollen deposition never declined distally and the low fruit and seed set of distal flowers remained even after supplementary pollination was provided.The flower-removal experiment indicated that inter-fruit competition for resources among flowers was common.The low P/o ratio of distal flowers in H.ventricosa might be favored because they were unable to obtain fitness by donat-ing pollen and siring seeds on other plants.our study may help to understand the adaptive significance of sex allocation among flow-ers within inflorescences of sexually reproducing hermaphrodites.

AGAMOUS AND TERMINAL FLOWER controls floral organ identity and inflorescence development in Medicago truncatula

Angiosperms integrate a multitude of endogenous and environmental signals to control floral development,thereby ensuring reproductive success.Here,we report the identification of AGAMOUS AND TERMINAL FLOWER(AGTFL),a novel regulator of floral development in Medicago truncatula.Mutation of AGTFL led to the transformation of carpels and stamens into numerous sepals and petals and altered primary inflorescence identity.AGTFL encodes a nucleus-localized proteincontaining a putative Myb/SANT-like DNA-binding domain and a PKc kinase domain.Molecular and genetic analyses revealed that AGTFL regulates the transcription of MtAGs and MtTFL1 to control floral organ identity and inflorescence development.

GLABROUS INFLORESCENCE STEMS regulates trichome branching by genetically interacting with SIM in Arabidopsis

Arabidopsis trichomes are large branched single cells that protrude from the epidermis. The first mor- phological indication of trichome development is an increase in nuclear content resulting from an initial cycle of endoreduplication. Our previous study has shown that the C2H2 zinc finger protein GLABROUS INFLORESCENCE STEMS (GIS) is required for trichome initiation in the inflorescence organ and for trichome branching in response to gibberellic acid signaling, although GIS gene does not play a direct role in regulating trichome cell division. Here, we describe a novel role of GIS, controlling trichome cell division indirectly by interacting genetically with a key endoreduplication regulator SIAMESE (SIM). Our molecular and genetic studies have shown that GIS might indireclty control cell division and trichome branching by acting downstream of SIM. A loss of function mutation of SIM signficantly reduced the expression of GIS. Futhermore, the overexpression of GIS rescued the trichome cluster cell phenotypes of sim mutant. The gain or loss of function of GIS had no significant effect on the expression of SIM. These results suggest that GIS may play an indirect role in regulating trichome cell division by genetically interacting with SIM.