Unraveling the regulatory network of flower coloration in soybean:Insights into roles of GmMYBA3 and GmMYBR1

Anthocyanins play crucial roles in pollen protection and pollinator attraction in flowering plants.However,the mechanisms underlying flower color determination and whether floral anthocyanin regulators participate in other processes remain largely unresolved in soybeans(Glycine max).In this study,we investigated the genetic components and mechanisms governing anthocyanin biosynthesis in soybean flowers.Molecular and genetic studies have characterized two antagonistic regulators,the positive activator GmMYBA3 and the negative repressor GmMYBR1,that modulate the gene expression of anthocyanin biosynthesis in soybean flowers.Further findings revealed a regulatory interplay between GmMYBA3 and GmMYBR1 bridged by GmTT8a,highlighting the complexity of anthocyanin regulation in different soybean organs.Exploration of additional soybean cultivars demonstrated the universality of GmMYBA3 and GmMYBR1 in regulating floral anthocyanin biosynthesis-related genes,with GmF3’5’H identified as a crucial determinant of white flower color.This study provides a molecular mechanism underlying soybean flower color determination,paving the way for the molecular modification of soybean flowers to probably enhance their resistance to abiotic stresses and attractiveness to pollinators.

Flavonoid content and expression analysis of flavonoid biosynthetic genes in herbaceous peony(Paeonia lactiflora Pall.)with double colors

Herbaceous peony（Paeonia lactiflora Pall.） is a famous flower with medicinal values, and its flowers have a number of medicinal constituents, especially flavonoids. In this study, a P. lactiflora cultivar with double colors including white outer-petal and yellow inner-petal was used as the experimental materials to perform the qualitative and quantitative analysis of flavonoids by high-performance liquid chromatograph-electrospray ionization-mass spectrometry（HPLC-ESI-MSn） and investigate the expression patterns of flavonoid biosynthetic genes using real-time quantitative polymerase chain reaction（Q-PCR）. The results showed that the colors of both petals gradually weakened with flower development. Moreover, one main anthocyanin composition（peonidin 3,5-di-O-glucoside） and five main anthoxanthin compositions（kaempferol di-hexoside, kaempferol-3-O-malonylglucoside-7-O-glucoside, quercetin-3-O-galactoside, luteolin-7-O-glucoside and isorhamnetin-3-O-glucoside） were found in the both, differing significantly in their peak areas only. Total anthocyanin, anthoxanthin and flavonoid contents in white outer-petal and yellow inner-petal gradually decreased during flower development, and were consistently higher in white outer-petal. Furthermore, the expression patterns of nine structural genes in P. lactiflora flavonoid biosynthetic pathway showed that the expression levels of phenylalanine ammonialyase gene（Pl PAL）, chalcone synthase gene（PlC HS）, flavanone 3-hydroxylase gene（PlF 3H）, anthocyanidin synthase gene（PlA NS） and UDP-glucoside： flavonoid 5-O-glucosyltransferase gene（Pl F5GT） in two petals basically presented declined tendencies, and transcription levels of Pl PAL, Pl CHS, Pl ANS, Pl F3 GT and Pl F5 GT also tended to be higher in white outer-petal, which was correlated with their flavonoid contents. These results would lay a solid foundation for the exploration and utilization of flavonoid resources in P. lactiflora flowers.

Regulatory mechanisms of rapeseed petal color formation:Current research status and future perspectives

Flower color,an important rapeseed character,has great practical value and research significance.It has become an area of intensive research in recent years.This paper summarizes the latest research progress on rape flower color in terms of variety,source,pigment composition,formation mechanism,and omics.Moreover,it provides an overview of rape flower color breeding and omics.

1-DE/MS Analysis of Proteins Related to the Spathe Color Variation in an Anthurium andraeanum Mutant

[Objectives] This study was conducted to explore the color variation mechanism of Anthurium andraeanum spathe at the protein level. [Methods]The differential proteins of wild type and its white mutant were separated and identified by using one-dimensional gel electrophoresis and mass spectrometry( 1-DE/MS). [Results] Compared with leaves and spadices,the 1-DE patterns of two kinds of spathe proteins were significantly different,and two different bands were detected in wild type spathes and mutant spathes respectively. The four significantly differential bands were selected and analyzed by mass spectrometry,and 138,111,70 and 427 proteins were identified respectively. The results of GO functional annotation analysis showed that the molecular functions of the proteins were mainly catalytic activity and binding,and the main biological processes involved were cellular process and metabolic process. Many proteins involved in the synthesis of anthocyanins and flavonoids,sugar metabolism and some resistance proteins were screened,indicating that the spathe color difference of A. andraeanum‘Pink champion'is not only related to anthocyanin anabolism,but also regulated by various metabolic pathways. [Conclusions]The study provides a new experimental basis for elucidating the molecular mechanism of the regulation of A. andraeanum flower color.

Effect of Paclobutrazol Application on Plant Growth and Flower Quality in Herbaceous Peony

Herbaceous peony(Paeonia lactiflora Pall.)is an important ornamental plant worldwide.In its natural state,P.lactiflora often manifests traits like rapidly elongating internodal growth,loose plant types,and soft inflorescence stems.However,very little has been known about the measures for controlling these traits.This study investigated the effect of applying paclobutrazol(PBZ)on the plant growth and flower quality in P.lactiflora.The results indicated that PBZ application reduced the plant height(8.05%),plant crown width(14.72%),and leaf area(10.90%),but increased the leaf thickness(18.18%)and stem diameter(over 11%)in P.lactiflora.Meanwhile,PBZ application was also found to increase the chlorophyll(Chl)a(29.63%),Chl b(33.33%),Chl a+b(30.56%),SPAD(27.32%),relative water content(0.47%),soluble sugar(5.09%)and activities of three antioxidant enzymes(superoxide dismutase 169.66%,peroxidase 3.59%,catalase 319.30%),but decreased the relative electrical conductivity(18.52%).Additionally,the application of PBZ was found to affect the flowering quality of P.lactiflora,increasing the flower diameter and fresh weight only in the flower-bud stage.This initiates the bloom stage,where there was a decrease in the total content of the aromatic compounds except for the flower-bud stage,and faded the flower color by reducing the content of anthocyanin.These results demonstrated that the application of PBZ can regulate the P.lactiflora plant types with no significant decrease in its ornamental values.This might provide a theoretical basis for further applying PBZ in P.lactiflora for use in urban landscape spaces.

Determination of Anthocyanins and Exploration of Relationship between Their Composition and Petal Coloration in Crape Myrtle (Lagerstroemia hybrid)

Petal coloration and pigment components in 12 American crape myrtle cultivars （Lagerstroemia indica x Lagerstroemia fauriei） and five Chinese crape myrtle cuItivars （L. indica hybrids） were studied. Color was measured by CIEL^＊a^＊b^＊ scale and anthocyanin composition of crape myrtle was determined using high-performance liquid chromatography coupled to photodiode array detection and electrospray ionization mass spectrometry. The presence of the previously reported delphinidin 3-O-glucoside, petunidin 3-O-glucoside and malvidin 3-O-glucoside were confirmed. Cyanidin 3-O-glucoside was identified in crape myrtle for the first time. We explored the relationship between petal color and anthocyanin contents by multiple linear regression analyses. The results indicated that total fiavones and fiavonols were important variables and contributed to blue-enhancing in crape myrtle. Based on anthocyanins and co-pigments analysis, flower color breeding in crape myrtle towards true-red and blue were discussed.

Discovery of Gynoecium Color Polymorphism in an Aquatic Plant

Flower color polymorphism exhibited by natural populations provides an opportunity for understanding the evolutionary mechanisms contributing to the diversity of floral morphology. However, little is known about the color polymorphism of female organs in flowering plants. Here we report gynoecium color polymorphism in Butornus urnbellatus （Butomaceae）, an emergent, aquatic monocot. Populations from Mishan, northeastern China comprised two morphs; gynoecia are either pink, as observed in other areas, or white. We measured floral traits and female fecundity in the two gynoecium color morphs in the field. There was no significant difference in plant height, pedicel length, and flower size including petal, sepal and gynoecium between the two morphs, but plants with pink gynoecia had wider inflorescence stalks, larger inner whorl anthers and produced more pollen and ovules than those with white gynoecia. Correspondingly, we found that seed production was significantly higher in the pink than in the white morph. This new finding suggested selection against white gynoecia in part because of low fecundity, consistent with the rarity of the white gynoecium morph in this species.

Study on Heredity Rules of Cyclamen persicum Colors

To identify the theoretic foundation for maintaining and improving high quality varieties and breeding new F1 hybrids, flower color segregation occurred in the offspring in both self-pollination and cross- pollination of varieties of different colors were investigated. The main results indicate that the heredity of Cyclamen persicum color follows both quantitative and qualitative hereditary regularity. All genes can be classified as two groups of the throat-gene and coronal-gene occupying different spots on the chromosome. The colored gene is the dominant gene, while the white gene is the recessive one. The gene groups and their quantity determine the color of cyclamen persicum. And sometimes the throat- gene and the coronal-gene take a recombination, forming a new type of flower.

The Melastoma dodecandrum genome and the evolution of Myrtales

Melastomataceae has abundant morphological diversity with high economic and ornamental merit in Myrtales. The phylogenetic position of Myrtales is still contested. Here, we report the chromosome-level genome assembly of Melastoma dodecandrum in Melastomataceae. The assembled genome size is299.81 Mb with a contig N50 value of 3.00 Mb. Genome evolution analysis indicated that M. dodecandrum,Eucalyptus grandis, and Punica granatum were clustered into a clade of Myrtales and formed a sister group with the ancestor of fabids and malvids. We found that M. dodecandrum experienced four whole-genome polyploidization events: the ancient event was shared with most eudicots, one event was shared with Myrtales, and the other two events were unique to M. dodecandrum. Moreover, we identified MADS-box genes and found that the AP1-like genes expanded, and AP3-like genes might have undergone subfunctionalization. The SUAR63-like genes and AG-like genes showed different expression patterns in stamens, which may be associated with heteranthery. In addition, we found that LAZY1-like genes were involved in the negative regulation of stem branching development, which may be related to its creeping features. Our study sheds new light on the evolution of Melastomataceae and Myrtales, which provides a comprehensive genetic resource for future research.