Abstract Background Brassica napus L. (2n = 38, AACC) is one of the most important oil crops and sources of protein for animal feed worldwide. Lignin is a large molecule aromatic polymer and a major cell wall component. However, lignin in the seed coat reduces the availability and restricts the development of rapeseed cake. Therefore, it is critical to reduce the lignin content of the seed coat. Here, high-lignin (H-lignin) and low-lignin (L-lignin) content recombinant inbred lines (RILs) were selected from an RIL population for analysis. Results The cross-section results indicated that the seed coat of the H-lignin lines was thicker than that of the L-lignin lines, especially the palisade layer. The seed coats and embryos at 35, 40 and 46 days after flowering (DAF) were subjected to RNA sequencing (RNA-Seq), and the expression of the BnPAL and BnC4H gene families in the lignin pathway was significantly higher in the H-lignin seed coat than in the L-lignin seed coat. The Bn4CL gene family also showed this trend. In addition, among the genes related to plant hormone synthesis, BnaC02g01710D was upregulated and BnaA07g11700D and BnaC09g00190D were downregulated in H-lignin lines. Some transcription factors were upregulated, such as BnNAC080 , BnNAC083 , BnMYB9 , BnMYB9-1 , BnMYB60 and BnMYB60-1 , while BnMYB91 was downregulated in H-lignin lines. Moreover, most genes of the flavonoid pathway, such as BnCHS and BnDFR , were strongly expressed in H-lignin seed coat. Conclusions In Our study, some key genes such as hormone synthesis genes, transcription factors and miRNAs related to lignin and flavonoid biosynthesis were identified. A regulatory model of B. napus seed coat lignin was proposed. These results provide new insight into lignin and flavonoid biosynthesis in B. napus .
Transcription factors (TFs) encoded by the lateral organ boundaries domain (LBD) gene family are known to control many plant-specific developmental processes. However, the comparative analysis of the LBD gene family in Rosaceae species and its expression pattern in mei remains unclear. Here, we identified a total of 406 LBDs in nine Rosaceae species, including 39 in black raspberry (Rubus occidentalis), 34 in strawberry (Fragaria vesca), 39 in Chinese rose (Rosa chinensis), 42 in peach (Prunus persica), 41 in apricot (Prunus armeniaca), 41 in mei (Prunus mume var. tortuosa), 60 in pear (Pyrus communis), 41 in hawthorn (Crataegus pinnatifida) and 69 in apple (Malus domenstica), respectively. The LBDs of nine Rosaceae species were classified into seven major subclasses. The chromosome localization, collinearity analysis, and gene duplication relationship revealed that segment duplication was the main driving force for the amplification of LBDs in the Rosoideae and Amygdaloideae. Ka/Ks analysis suggested most of the LBD gene pairs might be under purification selection. GO and cis-acting elements analysis showed that LBDs may play important roles in many biological processes and could respond to hormones and stresses. RNA-seq data showed that PmLBD17/19/41 genes contained both low-temperature and MeJA response elements and played a significant variation across different geographic locations and periods. PmLBD30, the ortholog of EgLBD29, exhibited an up-regulation followed by a decrease, which is hypothesized to possibly play a role in the formation of a weeping trait in mei. Our research offers important data about the development of the LBD family in Rosaceae and the subsequent validation of LBDs' functional genes in P. mume.
A prickle is an acuminate protuberance formed by the deformation of plant trichomes together with a few cortical cells. It is a type of multicellular eglandular trichome with special morphology, which originates from the phloem but is not connected to the xylem. Rosa rugosa is an important ornamental/commercial plant and an important raw material in the food and perfume industries. However, the firm prickles on its stems are inconvenient to field management, the harvesting of flowers and garden management. The TTG1 transcription factor related to the development of prickle was isolated from R. rugosa in the present study. Its expression patterns in different tissues and varieties were analyzed. Results showed the expression level of the RrTTG1 gene was highest in the leaves, followed by the stems, but was lower in the pericarps and petals. Moreover, the higher expression level of the RrTTG1 gene in all tissues of the ?Ciguo rose?, as compared with that of the ?Weihai wild rose?, follows the results of field morphological observation. Therefore, the RrTTG1 transcription factor is likely to regulate the development of rose prickles. This study allows for further discussion on the molecular mechanisms of prickle formation and development in R. rugosa and provides a molecular basis for the cultivation of roses with fewer or no prickles via genetic engineering.
AbstractBackgroundNitrogen (N) is very important for plant development, growth, and secondary metabolism.Lithocarpus polystachyusRehd, also called sweet tea, is known for its medicinal and food value. It contains several bioactive components, including phlorizin, with various pharmacological activities. Research has indicated a positive correlation between phlorizin and nitrogen (N) content inL. polystachyus.However, no reports have analyzed the effect of N treatment on phlorizin content and and reveal the molecular mechanisms of phlorizin synthesis.ResultsWe grewL. polystachyuswithout and with N fertilization at six levels (0, 25, 75, 125, 175, 225, and 275 mg per plant) and analyzed the plant growth status and leaf phlorizin content. These initial experiments revealed that 75 mg N/plant resulted in the best seedling height, ground diameter, crown width, and total phlorizin content inL. polystachyus. Subsequent comparison ofL. polystachyusplants grown without and with 75 mg/plant N fertilization identified 150 differentially accumulated metabolites in the leaves, including 42 flavonoids, using ultra-performance liquid chromatography-tandem mass spectrometry. Transcriptomic analysis by RNA sequencing detected 162 genes involved in flavonoid biosynthesis, among which 53 were significantly different between N-treated and untreated materials. Fertilization (75 mg N/plant) upregulated the expression levels of phenylalanine ammonia-lyase (PAL), 4-coumarate-CoA ligase (4CL), and phlorizin synthase (PGT1) but downregulated those of trans-cinnamate 4-monooxygenase (C4H) and chalcone isomerase (CHI), were related to the phlorizin synthesis. Integrated analysis of the transcriptome and metabolome found that the increase in phlorizin via the flavonoid biosynthetic pathway after N fertilization was consistent with the the expression levels upregulation of phlorizin biosynthetic genes. Quantitative real-time PCR (qRT-PCR) analysis validated the RNA-sequencing data. Thus, these observations indicated that the expression levels ofPAL,PGT1, 5-O-(4-coumaroyl)-D-quinate 3'-monooxygenase (C3'H),C4H, and shikimate O-hydroxycinnamoyltransferase (HCT) genes were related to phlorizin metabolism inL. polystachyusunder N fertilization.ConclusionsOverall, understanding the molecular mechanism of phlorizin synthesis will help improve plant quality and serve as a reference for further pharmacological studies.
Prunus mume is the only plant in the genus Prunus of the Rosaceae family with a characteristic floral scent, and the main component of this scent is benzyl acetate. By contrast, benzyl acetate is not synthesized in Prunus persica flowers. Here, we searched for benzyl alcohol acetyltransferase (BEAT) genes based on genomic data from P. mume and P. persica and found 44 unique PmBEATs in P. mume. These genes, which were mainly detected in clusters on chromosomes, originated from gene duplication events during the species evolution of P. mume, and retroduplication and tandem duplication were the two dominant duplication patterns. The genes PmBEAT34, PmBEAT36 and PmBEAT37, which were generated by tandem duplication, were highly expressed in flowers, and their highest levels were detected during the blooming stage. In vitro, PmBEAT34, PmBEAT3, and PmBEAT37 all had benzyl alcohol acetyltransferase activity that was localized in the cytoplasm. Overexpression of the PmBEAT36 or PmBEAT37 genes increased benzyl acetate production in the petal protoplasts of P. mume, and interference in the expression of these genes slightly decreased the benzyl acetate content. In addition, light and temperature regulated the expression of the PmBEAT34, PmBEAT36 and PmBEAT37 genes. According to these results, we hypothesize that the expansion of the PmBEAT genes in the genome induce the characteristic floral scent of P. mume.
Chrysanthemum morifolium is one of the most important global cut flower and pot plants, and has been cultivated worldwide. However, limited genomic resources are available and the molecular mechanisms involved in the two morphologically distinct floret developmental cycles in chrysanthemum remain unclear. The transcriptomes of chrysanthemum ray florets, disc florets and leaves were sequenced using Illumina paired-end sequencing technology. In total, 16.9 G reads were assembled into 93,138 unigenes with an average length of 738 bp, of which 44,364 unigenes showed similarity to known proteins in the Swissprot or NCBI non-redundant protein databases. Additionally, 26,320, 22,304 and 13,949 unigenes were assigned to 54 gene ontology (GO) categories, 25 EuKaryotic Orthologous Groups (KOG) categories, and 280 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, respectively. A total of 1863 differentially expressed genes (DEGs) (1210 up-regulated and 653 down-regulated) were identified between ray florets and disc florets, including genes encoding transcription factors and protein kinases. GO and KEGG pathway enrichment analyses were performed on the DEGs to identify differences in the biological processes and pathways between ray florets and disc florets. The important regulatory genes controlling flower development and flower organ determination, as well as important functional genes in the anthocyanin biosynthetic pathway, were identified, of which two leucoanthocyanidin dioxygenase-encoding genes showed specific expression in ray florets. Lastly, reverse transcription quantitative PCR was conducted to validate the DEGs identified in our study. Comparative transcriptome analysis revealed significant differences in patterns of gene expression and signaling pathways between ray florets and disc florets in Chrysanthemum morifolium. This study provided the first step to understanding the molecular mechanism of the differential development of ray florets and disc florets in chrysanthemum, and also provided valuable genomic resources for candidate genes applicable for the breeding of novel varieties in chrysanthemum.
The growing features and yield of manganese deficiency rice seedling from dry nursery were studied in Linjiang Village of Wenjiang County, Sichuan Province, when they were transplanted to paddy soil and upland. The experiment showed that except the height of manganese deficiency rice seedling was not significant difference with normal rice seedling, the other features including tillerings, fringings, grain numbers in one ear, one thousand seed weight and yields were lower than those of normal rice seedling. If the manganese deficiency rice seedling is use in farm land, no matter what systems are used such as flooding, plastic film mulch and wheat straw mulch and no matter what methods are used to remedy them, the yield of it can not get to the yield by using normal rice seedling.
Abstract The developmental process that produces the ornate petals of the China rose ( Rosa chinensis ) is complex and is thought to depend on the balanced expression of a functionally diverse array of genes; however, the molecular basis of rose petal development is largely unknown. Here, petal growth of the R. chinensis cultivar ‘Old Blush’ was divided into four developmental stages, and RNA-seq technology was used to analyse the dynamic changes in transcription that occur as development progresses. In total, 598 million clean reads and 61,456 successfully annotated unigenes were obtained. Differentially expressed gene (DEG) analysis comparing the transcriptomes of the developmental stages resulted in the identification of several potential candidate genes involved in petal development. DEGs involved in anthocyanin biosynthesis, petal expansion, and phytohormone pathways were considered in depth, in addition to several candidate transcription factors. These results lay a foundation for future studies on the regulatory mechanisms underlying rose petal development and may be used in molecular breeding programs aimed at generating ornamental rose lines with desirable traits.
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