Yan Qu

Camellia reticulata ‘Tongzimian’ is the lightest-colored cultivar within the species, yet the molecular mechanism underlying its color formation remains elusive. In this study, ‘Tongzimian’ was used to observe phenotypic characteristics during flowering. Through multi-omics analyses, key substances and genes associated with petal fading were identified, clarifying the role of the CrANS gene in regulating floral coloration. Targeted anthocyanin metabolomics showed that procyanidin is the main pigment in ‘Tongzimian’ petals, with cyanidin serving as the key pigment driving color transformation. Transcriptome analysis revealed that low CrANS expression at full bloom is the primary factor reducing cyanidin content. Overexpressing CrANS demonstrated that the gene strongly promotes anthocyanin synthesis in tobacco corollas, thereby deepening flower color. The study suggests that a balance between cyanidin and procyanidin is central in regulating petal color transformation. Collectively, this research provides a novel framework for flower color dilution and supports molecular breeding of flower color in C. reticulata .

Meconopsis integrifolia is a famous alpine flower widely admired for its striking yellow flowers, yet the molecular mechanisms underlying this unique pigmentation remain poorly understood. Through integrated metabolomic and transcriptomic analyses across three key floral developmental stages, we identified 87 flavonoids, with flavonols constituting the major differential metabolites. Kaempferol 3‐β‐D‐glucopyranoside, quercetin 3‐O‐sophoroside and quercetin 3‐O‐galactoside were the predominant flavonols, exhibiting a progressive decrease during petal development. We further cloned two pivotal biosynthetic genes, MiFLS2 and MiDFR6 , and western blot analysis and subcellular localisation revealed that both proteins are distributed in the cytoplasm and nucleus. Functional verification in transgenic tobacco revealed that MiFLS2 overexpression increased flavonol accumulation while suppressing anthocyanin biosynthesis, leading to lighter‐coloured flowers. In contrast, MiDFR6 overexpression coordinately up‐regulated both flavonol and anthocyanin pathways but ultimately promoted redder pigmentation, indicating distinct regulatory roles. Critically, we uncovered a possible multilayer regulatory mechanism: The expression of MiFLS2 is negatively correlated with that of upstream flavonoid genes and MiDFR6 , hinting at a possible feedback inhibitory role. Conversely, MiDFR6 overexpression is associated with the coordinated upregulation of multiple structural genes in the flavonoid biosynthesis pathway, implying a putative positive regulatory function. Metabolite analysis confirmed that pelargonidin‐3‐O‐rutinoside, cyanidin‐3‐O‐rutinoside, and kaempferol 3‐β‐D‐glucopyranoside are key contributors to flower colour variation. Ultimately, the high MiFLS2 / MiDFR6 expression ratio in M. integrifolia suggests a key factor in controlling the biochemical fate of dihydroflavonols, conferring yellow coloration. Our findings provide novel insights into the competitive and regulatory mechanisms controlling flower colour in alpine plants.

Flower color is one of the most ornamental values of Meconopsis wilsonii, but very limited studies have been reported on its flower color formation. The UDP-glycosyltransferase (UGT) gene family plays a crucial role in plant flower color formation. In this study, the full-length transcriptome data of M. wilsonii was used to identify MwUGTs, focusing on protein physicochemical properties’ subcellular localization, and phylogenetic relationships. In addition, sequence analysis, expression pattern analysis, subcellular localization, and functional validation of MwUGT2 were also performed. A total of 26 MwUGTs were identified in full-length transcriptome and clustered into eight subgroups. Phylogenetic analysis and KEGG database annotation showed that MwUGT2 is associated with anthocyanin synthesis and accumulation. Subsequently, based on the expression of MwUGT2 during flower development and in different tissues, it was preliminarily determined that MwUGT2 plays a role in the flower bud stage. Subcellular localization assays suggested that MwUGT2 is present in the nucleus and cytoplasm. Overexpression in Nicotiana tabacum showed that MwUGT2 significantly increased the content of Cyanidin-3-O-glucoside and resulted in dark pink flowers in transgenic plants. In summary, our findings suggest that MwUGT2 plays a crucial role in the biosynthesis of anthocyanin and will also contribute to understanding the mechanisms of flower color formation in M. wilsonii.

Meconopsis integrifolia is an endangered Tibetan medicinal plant with significant medicinal and ornamental value. Understanding its genetic diversity and structure is crucial for its sustainable utilization and effective conservation. Here, we develop a set of SSR markers based on transcriptome data to analyze the genetic diversity and structure of 185 individuals from 16 populations of M. integrifolia. The results indicate that M. integrifolia exhibits relatively high genetic diversity at the species level (the percentage of polymorphic bands PPB = 91.67%, Nei’s genetic diversity index He = 0.2989, Shannon’s information index I = 0.4514) but limited genetic variation within populations (PPB = 12.08%, He = 0.0399, I = 0.0610). The genetic differentiation among populations is relatively high (the coefficient of gene differentiation GST = 0.6902), and AMOVA analysis indicates that 63.39% of the total variation occurs among populations. This suggests that maintaining a limited number of populations is insufficient to preserve the overall diversity of M. integrifolia. Different populations are categorized into four representative subclusters, but they do not cluster strictly according to geographical distribution. Limited gene flow (Nm = 0.2244) is likely the main reason for the high differentiation among these populations. Limited seed and pollen dispersal abilities, along with habitat fragmentation, may explain the restricted gene flow among populations, highlighting the necessity of conserving as many populations in the wild as possible.

Camellia reticulata Lindl., also known as Yunnan Camellia, is an important ornamental plant in China, especially for its large and stunning flowers. A comprehensive understanding of their coloration mechanisms can aid breeders in developing new cultivars and improving their ornamental value; however, it is still unclear in Yunnan Camellia, especially in mixed-color flowers. In this study, we conducted metabolic and transcriptomic comparison analyses to investigate the coloration differences in three Yunnan Camellia cultivars: C. reticulata ‘Shizitou’ (SZT), C. reticulata ‘Damanao’ (MN), and C. reticulata ‘Tongzimian’ (TZM). Our results revealed that the initial flowering stage may play a critical role in the color change of MN. Metabolome analysis demonstrated that cyanidin was the primary anthocyanin in SZT and MN’s red region, while its content was low in TZM and MN’s white region. According to the transcriptome analysis, the anthocyanins biosynthesis pathway was reconstructed in Yunnan Camellia, and the low expression of CHS was detected in TZM and MN’s white region, while ANR maintained a high expression level, which may lead to the low content of cyanidin in them. Transcription factors MYBs, bHLH, and bZIP may play a key role in regulating anthocyanin-structural genes. The co-expression analysis showed that the meristem tissue may play a crucial role in the formation of the mixed white-red color in MN. Our study enriched the genetic basis of flower coloration differences in Yunnan Camellia which will be a valuable genomic resource to understanding the biology of coloration formation and for breeding the Camellia cultivars.

Meconopsis punicea (Papaveraceae) is only distributed in the alpine areas of the Qinghai Plateau (QHP) and Hengduan Mountains (HDM) in China. As an important ornamental flower and traditional Tibetan medicine, in addition to habitat loss, its higher economic value drives over-exploitation of this resource, which has accelerated the reduction of its distribution. How to make its protection strategy is still unfounded as unclear genetic diversity characteristics of M. punicea. In this study, we analyzed the genetic diversity and phylogeographic structures of M. punicea representing 11 populations 106 individuals using 4-locus dataset (matK, ndhF, rbcL and rpb2, a total of 2576 bp). A total of 76 sequence types were identified (Hd = 0.987, Pi = 0.00447). Six phylogenetic clades were recognized, and 3 clades were restricted to unique geographic distribution (Clade A corresponded to population SD, B to LT, and C to BL). The zoige area was referred as the differentiation center and a glacial refuge of M. punicea. M. punicea most likely originated from the southern HDM in the early Miocene (~ 22 Myr). Two dispersal routes were suggested and the ecological and geographical difference were revealed as the main driving forces for species differentiation of M. punicea. The suitable distribution area was predicted about 158,000 km² mainly in Sichuan, Gansu and Qinghai. Our current results provide much clear and detailed understanding for the diversity and geographical spatial distribution of the endemic alpine plant M. punicea. It will also be able to provide theoretical guidance for formulating the urgently needed protection strategies of M. punicea.

Summary: Given the rising risk of extreme weather caused by climate change, enhancement of abiotic stress resistance in crops is increasingly urgent. But will the development of stress‐resistant cultivars come at the cost of yield under ideal conditions? We hypothesize that this need not be inevitable, because resistance alleles with minimal pleiotropic costs may evade artificial selection and be retained in crop germplasm. Genome‐wide association (GWA) analyses for variation in plant performance and flooding response were conducted in cultivated sunflower, a globally important oilseed. We observed broad variation in flooding responses among genotypes. Flooding resistance was not strongly correlated with performance in control conditions, suggesting no inherent trade‐offs. Consistent with this finding, we identified a subset of loci conferring flooding resistance, but lacking antagonistic effects on growth. Genetic diversity loss at candidate genes underlying these loci was significantly less than for other resistance genes during cultivated sunflower evolution. Despite bottlenecks associated with domestication and improvement, low‐cost resistance alleles remain within the cultivated sunflower gene pool. Thus, development of cultivars that are both flooding‐tolerant and highly productive should be straightforward. Results further indicate that estimates of pleiotropic costs from GWA analyses explain, in part, patterns of diversity loss in crop genomes.