Rice Flower Research Articles

Effects of high-protein feeds on growth, free amino acid metabolism and protein metabolism-related genes in larvae and juveniles of rice flower carp (Procypris merus)

The effect of dietary protein on fish is widely studied. However, the high-protein diet effects and mechanisms on growth and amino acid metabolism in Procypris merus remain unclear. In this study, we investigated the effect of dietary protein levels (38 %, 44 %, 50 %) on the growth performance and amino acid contents in larvae and juveniles of P. merus. Transcriptome sequencing was used to study the adaptation mechanism of P. merus to a high-protein diet. The final length, specific growth rate, and protein efficiency ratio were remarkably decreased with increasing dietary protein levels, while the amino acid content of the body was significantly increased. In addition, 370,513,858 reads were obtained and assembled into 278,939 unigenes, with an average length of 559 bp. KEGG analysis revealed that differentially expressed genes were mainly involved in protein digestion and absorption, carbohydrate digestion and absorption, starch and sucrose metabolism, and pancreatic secretion. Moreover, high-protein increased the expression of genes involved in trypsin (prss, ctrl, cpa, cpb), peptide transporter (pept), amino acid transporter (b0at1), and gluconeogenesis (g6pase), which could digest and absorb the dietary protein, and converse amino acids into energy, resulting in adaption to a high-protein diet.

Callose Deficiency Modulates Plasmodesmata Frequency and Extracellular Distance in Rice Pollen Mother and Tapetal cells.

Fertilization relies on pollen mother cells able to transit from mitosis to meiosis to supply gametes. This process involves remarkable changes at the molecular, cellular and physiological levels including (but not limited to) remodelling of the cell wall. During the meiosis onset, cellulose content at the pollen mother cell walls gradually declines with the concurrent deposition of the polysaccharide callose in anther locules. We aim to understand the biological significance of cellulose-to-callose turnover in pollen mother cells walls using electron microscopic analyses of rice flowers. Our observations indicate that in wild type rice anthers, the mitosis-to-meiosis transition coincides with a gradual reduction in the number of cytoplasmic connections called plasmodesmata. A mutant in the Oryza sativa callose synthase GSL5 (Osgsl5-3), impaired in callose accumulation in premeiotic and meiotic anthers, displayed a greater reduction in plasmodesmata frequency among pollen mother cells and tapetal cells suggesting a role for callose in plasmodesmata maintenance. In addition, a significant increase in extracellular distance between pollen mother cells and impaired premeiotic cell shaping was observed in the Osgsl5-3 mutant. The results suggest that callose-to-cellulose turnover during mitosis-meiosis transition is necessary to maintain cell-to-cell connections and optimal extracellular distance among the central anther locular cells. Findings of this study contribute to our understanding of the regulatory influence of callose metabolism during meiosis initiation in flowering plants.

Assessment of florpyrauxifen-benzyl in water-seeded rice systems as affected by application timing

Florpyrauxifen-benzyl (FPB) is a novel auxin mimic rice herbicide used to control selected grasses, sedges, and broadleaves. Field experiments were conducted in 2020–2022 to 1) characterize the effects of FPB on rice crop safety and weed control when applied alone or in a mixture, 2) determine the FPB application timing to optimize smallflower umbrella sedge (SMF) control, and 3) evaluate the effect of late season application on rice flower sterility. In the first study, FPB was applied alone at 15, 30, and 60 g ai ha−1 and in mixture with bispyribac-sodium, penoxsulam, and propanil. FPB applied alone at 30 g ha−1 at 4–5-leaf (LF) rice stage controlled more than 80% of watergrasses, ricefield bulrush, and SMF and more than 99% of all broadleaf weeds at 28 days after treatment (DAT). The mixture treatments of FPB plus bispyribac-sodium applied at maximum use rate had the greatest grass weed control whereas, FPB plus propanil at the maximum use rate provided the greatest sedge control. In the second study, FPB at 40 g ha−1 was applied at 1-LF, 10-, 15-, 20-, and 25-cm tall SMF, where treatments controlled 95%, 86%, 89%, 87%, and 85% of SMF at 42 DAT, respectively. In the third study, FPB at 40 and 80 g ha−1 rate was applied at rice panicle initiation (PI) and 50% flowering (FL) growth stages. While the weed control was more than 90% at 42 DAT for all applications, the FL stage application caused 26% and 35% rice panicle blanking at 40 and 80 g ha−1 rate, respectively. This research suggests, the window of FPB application should be from 2-LF rice to rice PI stage to ensure crop safety and highest weed control.

ROS-Induced Autophagy of Skeletal Muscle Confers Resistance of Rice Flower Carp (Cyprinus carpio) to Short-Term Fasting.

Starvation is one of the main stresses for fish due to food shortage, the evasion of predators, and intraspecific competition. This research evaluated the impact of brief fasting periods on reactive oxygen species (ROS) levels, antioxidant response, mRNA expression of antioxidants, autophagy-related signaling genes, and autophagosome development in the muscle tissue of rice flower carp. Following a three-day fasting period, the levels of ROS and MDA rose. Additionally, after 3 d of fasting, there was a notable upregulation of NRF2 and significant increases in the levels of GSH and the activities of enzymes such as SOD, CAT, GST, GR, and GPX, while the expression of the autophagy marker gene LC3B did not change (p < 0.05). After 7 d of fasting, the content of the ROS, the activity of SOD and GR, and the GSH content reached the maximum (p < 0.05). Concurrently, there was a significant rise in the quantity of autophagosomes. An RT-qPCR analysis revealed that seven d of starvation significantly elevated the mRNA expression of genes associated with the initiation and expansion of autophagosome membranes, vesicle recycling, and cargo recruitment, including ULK1, BECLIN1, LC3B, ATG3, ATG4B, ATG4C, ATG5, ATG9, and P62. After feeding resumed for 3 d, the mRNA level of BECLIN1, ATG3, ATG4B, ATG4C, ATG5, LC3B, and P62 still remained at a high level. The LC3II protein reached its highest level. All autophagy-related gene expression decreased in the 7-day resumed feeding group. Our data implied that short-term fasting can cause oxidative stress and disrupt the antioxidant system first and then induce autophagy in the muscles of rice flower carp. These findings shed light on how fasting affects muscle homeostasis in fish. ROS-induced autophagy of the skeletal muscle may confer the resistance of rice flower carp to short-term fasting.

Adjustments of flower opening time and duration in tropical rice (Oryza sativa ssp. indica) landraces in response to heat stress

AbstractBased on our primary database of the flower opening time (FOT) and flower exposure duration (FED) of 1114 rice (Oryza sativa ssp. indica) landraces, we examined the influences of growing season, sunrise time as well as day maximum and minimum temperatures on the anthesis behaviour of indica rice landraces of South and Southeast Asia, flowering in summer and winter in 3 consecutive years (2020–2022). We also compared the FOT and FED on sunny and cloudy days of a small set of landraces, and also during summer and winter. Our data show that rice florets tend to open later in the morning and lengthen the sunrise‐to‐anthesis duration (SAD) on hotter sunny days during tropical summer than during winter and on cloudy days. These findings contradict the widely held conjecture, based on studies conducted at colder latitudes, that rice flowers open earlier in the morning to avoid heat stress. We propose that indica rice landraces are sufficiently adapted to tropical summer because they were selected and bred over millennia to withstand heat stress during tropical summer, so their FOT and SAD are weakly influenced by high day temperatures. However, the significant reduction in FED of these landraces, whose flowers open later in mid‐day, seems to be an adaptive mechanism to avoid longer exposure to rising air temperature approaching day maximum temperature.

Microplastics have additive effects on cadmium accumulation and toxicity in Rice flower carp (Procypris merus)

Procypris merus, a local fish species found in Guangxi, China is often exposed to both microplastics (MPs) and Cd. However, it remains unclear how these two pollutants affect P. merus. Therefore, we investigated the effects of MPs on Cd accumulation in P. merus. To this end, P. merus was separately exposed to Cd and MPs (500 μg/L) or their combination for 14 days. We found that MPs enhanced Cd accumulation in liver and gills of P. merus. Further, both the single-contaminant (MP and Cd) and combined treatments resulted in lesions in these two tissues, with more severe damage associated with the combined treatment. Even though the effect of MP on the antioxidant defense system of P. merus was limited, the Cd-only and combined treatments considerably affected the antioxidant parameters of P. merus, with the combined treatment showing a stronger effect. GO and KEGG analyses revealed that the differentially expressed genes (DEGs; TNF-related apoptosis-inducing ligand receptor, trail-r) in the Cd-only treatment group were enriched for immune-related GO terms and cell growth and death related pathways, indicating that Cd toxicity affected immune defense in P. merus. The MP-only treatment downregulated DEGs (acyl-CoA synthetase long chain family member 1a, acsl1a) related to lipid metabolism, possibly leading to lipid accumulation in the liver. The combined treatment also upregulated DEGs (aspartate aminotransferase 1, ast 1) associated with immune-related GO terms and amino acid metabolism pathways, suggesting that it affected immune function in P. merus, thereby negatively impacting its health. Results indicated that MPs have additive effects on Cd accumulation and toxicity in rice flower carp. Consequently, MPs ingested by P. merus can promote Cd accumulation, more adverse effects on the health may occur after combined exposure, which can eventually reach humans through the food chain and pose potential risks to human health.

Hybrid Rice Production: A Worldwide Review of Floral Traits and Breeding Technology, with Special Emphasis on China.

Rice is an important diet source for the majority of the world's population, and meeting the growing need for rice requires significant improvements at the production level. Hybrid rice production has been a significant breakthrough in this regard, and the floral traits play a major role in the development of hybrid rice. In grass species, rice has structural units called florets and spikelets and contains different floret organs such as lemma, palea, style length, anther, and stigma exsertion. These floral organs are crucial in enhancing rice production and uplifting rice cultivation at a broader level. Recent advances in breeding techniques also provide knowledge about different floral organs and how they can be improved by using biotechnological techniques for better production of rice. The rice flower holds immense significance and is the primary focal point for researchers working on rice molecular biology. Furthermore, the unique genetics of rice play a significant role in maintaining its floral structure. However, to improve rice varieties further, we need to identify the genomic regions through mapping of QTLs (quantitative trait loci) or by using GWAS (genome-wide association studies) and their validation should be performed by developing user-friendly molecular markers, such as Kompetitive allele-specific PCR (KASP). This review outlines the role of different floral traits and the benefits of using modern biotechnological approaches to improve hybrid rice production. It focuses on how floral traits are interrelated and their possible contribution to hybrid rice production to satisfy future rice demand. We discuss the significance of different floral traits, techniques, and breeding approaches in hybrid rice production. We provide a historical perspective of hybrid rice production and its current status and outline the challenges and opportunities in this field.

A trick for a treat: False smut pathogen manipulates plant defense to gain access to rice flower.

A trick for a treat: False smut pathogen manipulates plant defense to gain access to rice flower.

Dietary lipid-induced changes in antioxidant status, lipid metabolism and flesh quality of juvenile rice flower carp (Cyprinus carpio)

Lipids are necessary nutrients for fish and play an important role in growth and metabolism. This study analyzed the effects of dietary lipid levels on growth performance, flesh quality, antioxidant status, and lipid metabolism of juvenile rice flower carp (Cyprinus carpio). The results showed that the weight gain rate and specific growth rate increased initially and then decreased with increasing dietary lipid levels, which 5.82 % dietary lipid level had the best growth in rice flower carp. Dietary lipid levels also affect the nutrition and quality of fish flesh. With the increase of dietary lipid levels, the hardness, adhesiveness, springiness, gumminess and chewiness of muscle showed a trend of increase and then decrease. Moreover, there are similar changes in the activity of antioxidant enzymes in the muscle, and the content of ROS and MDA was significantly higher than other levels at 11.80 % dietary lipid level. The expression of Nrf2 mRNA and some downstream antioxidant enzyme genes was the contrary. Furthermore, the content of TG, TC, and LDL-C in serum and liver increased with increasing dietary lipid levels. Meanwhile, it was observed that the lipid accumulation increased in the liver. The mRNA expression of ATGL and CPT1 genes associated with lipid metabolism in liver increased firstly and then decreased, the expression of FASN, PPARγ, and SREBP1 gradually increased, and reached its maximum at 11.8 % dietary lipid level. The above results showed that the growth performance of juvenile rice flower carp was optimal when the dietary lipid level of 5.82 %, and the nutrition and quality of fish flesh also has good effects. However, the dietary lipid level of 11.80 % inhibited the weight gain and induced oxidative stress and lipid metabolism disorders of rice flower carp, which can affect their flesh quality and health.

Rice false smut virulence protein subverts host chitin perception and signaling at lemma and palea for floral infection.

The flower-infecting fungus Ustilaginoidea virens causes rice false smut, which is a severe emerging disease threatening rice (Oryza sativa) production worldwide. False smut not only reduces yield, but more importantly produces toxins on grains, posing a great threat to food safety. U. virens invades spikelets via the gap between the 2 bracts (lemma and palea) enclosing the floret and specifically infects the stamen and pistil. Molecular mechanisms for the U. virens-rice interaction are largely unknown. Here, we demonstrate that rice flowers predominantly employ chitin-triggered immunity against U. virens in the lemma and palea, rather than in the stamen and pistil. We identify a crucial U. virens virulence factor, named UvGH18.1, which carries glycoside hydrolase activity. Mechanistically, UvGH18.1 functions by binding to and hydrolyzing immune elicitor chitin and interacting with the chitin receptor CHITIN ELICITOR BINDING PROTEIN (OsCEBiP) and co-receptor CHITIN ELICITOR RECEPTOR KINASE1 (OsCERK1) to impair their chitin-induced dimerization, suppressing host immunity exerted at the lemma and palea for gaining access to the stamen and pistil. Conversely, pretreatment on spikelets with chitin induces a defense response in the lemma and palea, promoting resistance against U. virens. Collectively, our data uncover a mechanism for a U. virens virulence factor and the critical location of the host-pathogen interaction in flowers and provide a potential strategy to control rice false smut disease.

Study on SERS substrate preparation of rice flower type silver/titanium nitride thin films and detection of Rhodamine 6G

Study on SERS substrate preparation of rice flower type silver/titanium nitride thin films and detection of Rhodamine 6G

Neofunctionalization of B-class genes in regulating rice flower development

Neofunctionalization of B-class genes in regulating rice flower development

OsGSTU34, a Bz2-like anthocyanin-related glutathione transferase transporter, is essential for rice (Oryza sativa L.) organs coloration

Anthocyanins are a flavonoid compound known as one of the most important chromogenic substances. They play several functions, including health promotion and sustaining plants during adverse conditions. They are synthesized at the endoplasmic reticulum and sequestered in the vacuole. In this work, we generated knock-out lines of OsGSTU34, a glutathione transporter's tau gene family, with no transgene line and off-target through CRISPR/Cas9 mutagenesis and highlighted the loss of pigmentation in rice flowers, leaves, stems, shoots, and caryopsis. The anthocyanin quantification in the wild-type BLWT and mutant line BLG34-8 caryopsis showed that cyanidin-3-O-glucoside (C3G) and peonidin-3-O-glucoside (P3G) were almost undetectable in the mutant line. A tandem mass tag (TMT) labeling proteomic analysis was conducted to elucidate the proteomic changes in the BLWT and BLG34-8. The result revealed that 1175 proteins were altered, including 408 that were down-regulated and 767 that were upregulated. The accumulation of the OsGSTU34-related protein (Q8L576), along with several anthocyanin-related proteins, was down-regulated. The enrichment analysis showed that the down-regulated proteins were enriched in different pathways, among which the phenylpropanoid biosynthesis pathway, flavonoid biosynthesis metabolites, and anthocyanin biosynthesis pathway. Protein interaction network prediction revealed that glutathione-S-transferase (Q8L576) was connected to the proteins involved in the flavonoid and anthocyanin biosynthesis pathways, such as flavanone 3-dioxygenase 1 (Q7XM21), leucoanthocyanidin dioxygenase 1 (Q93VC3), 4-coumarate-CoA ligase 2 (Q42982), phenylalanine ammonia-lyase (P14717), chalcone synthase 1 (Q2R3A1), and 4-coumarate-CoA ligase 5 (Q6ZAC1). However, the expression of the most important anthocyanin biosynthesis gene was not altered, suggesting that only the transport mechanism was affected. Our findings highlight new insight into the anthocyanin pigmentation in black rice and provide new perspectives for future research.

Estimating rice flower intensity using flower spectral information from unmanned aerial vehicle (UAV) hyperspectral images

Growth monitoring of rice is of great significance to food security of human society. Rice flowering is an important growing stage for grain formation, and flower intensity is the dominant factor in determining rice yield. The estimation of flower intensity helps us to know the rice yield in advance. This research proposed a series of the flower index (FI) to monitor status of rice flowers by developing flower intensity estimation models using stepwise multiple linear regression (SMLR) and random forest (RF), and their performance was compared to the models developed by vegetation indices (VI) of some key growth stages. The FI that in types of normalization (NDFI), ratio (RFI) and differences (DFI) were tested. The involved FIs in the FI-based models were those in type of difference (DFI) that obtained by difference of reflectance before and after flowering (DR) and their first derivative (DR’). The FIs of ten consecutive days during the flowering were obtained and their correlations with flower intensity showed that FIs of the late flowering (the 8th day, 9th day and 10th day) were more significantly correlated to flower intensity than those at the early or mid-flowering, with the maximum correlation coefficient of 0.702 given by FIs in difference type formed by DR’. The accuracy assessment of flower intensity estimation models showed that FI-based models had the equivalent accuracies to VI-based models, especially for the SMLR model that based on four FIs, which had R2 = 0.707, MAPE = 10.54%, rRMSE = 11.39%, was comparable to the model that developed by three VIs of the booting, heading and jointing stages (R2 = 0.751, MAPE = 8.99%, rRMSE = 10.31%). The promising results of FIs in estimating flower intensity make the simple data acquisition possible and provide an alternative way to get information about rice yield.

LAX1, functioning with MADS-box genes, determines normal palea development in rice

Normal floral organ development in rice is necessary for grain formation. Many MADS-box family genes that belong to ABCDE model have been widely implicated in rice flower development. The LAX1 allele encodes a plant-specific basic helix-loop-helix (bHLH) transcription factor, which is the main regulator of axillary meristem formation in rice. However, the molecular mechanisms of LAX1 allele together with MADS-box family genes underlying palea development have not been reported. We found a short palea mutant plant in a population of indica rice variety 9311 treated with cobalt 60. We report the map-based cloning and characterization of lax1-7, identified as a new mutant allele of the LAX1 locus, and the role of its wild-type allele LAX1 in rice palea development. Through complementary experiments, combined with genetic and molecular biological analyses, the function of the LAX1 allele was determined. We showed that LAX1 allele is expressed specifically in young spikelets and encodes a nucleus-localized protein. In vitro and in vivo experiments revealed that the LAX1 protein physically interacts with OsMADS1, OsMADS6 and OsMADS7. The LAX1 allele is pleiotropic for the maintenance of rice palea identity via cooperation with MADS-box genes and other traits, including axillary meristem initiation, days to heading, plant height, panicle length and spikelet fertility.

Individual and combined effects of microplastics and cadmium on intestinal histology and microflora of Procypris merus

Microplastics (MPs) and their interactions with heavy metals have attracted considerable attention worldwide. In Guangxi, China, cadmium (Cd) pollution is ubiquitous in aquatic environments. Rice flower carp (Procypris merus) is popular in Guangxi, playing an important role in the economic development of the region. The effects of combined exposure to MPs and Cd on P. merus remain unclear consequently the present study was performed to determine the individual (500 µg/L Cd (Cd) or 500 µg/L MPs (MP)) and combined effects of MPs and Cd (500 µg/L Cd + 500 µg/L MPs (Cd + MP)) on the intestinal histology and microflora of P. merus after an exposure of 14 days. The intestinal structure was damaged in all treatment groups, and severe necrosis of the mucous layer was found in the MP and Cd + MP groups. Similarly, the number of goblet cells increased in all treatment groups, but was higher in the MP and Cd + MP groups. Alpha diversity indices of the gut microbiota were influenced by the individual or combined effects of exposure. At the phylum level, the abundance of Firmicutes was lower in MP group than Cd and Cd + MP group, and the Firmicutes/Bacteroidetes ratio was significantly decreased (p = 0.021) in MP group. At the genus level, Streptococcus, a genus that might be involved in controlling the incidence of intestinal inflammation, was also found to be significantly decreased in the MP group (p = 0.029). Consistent with these results, gut metabolic function was disrupted in the present study. Overall, the above results suggest that exposure to combined Cd and MPs could result in inflammatory disease in P. merus, which was potentially mainly due to MPs stress.

Advances on the Study of Diurnal Flower-Opening Times of Rice

The principal goal of rice (Oryza sativa L.) breeding is to increase the yield. In the past, hybrid rice was mainly indica intra-subspecies hybrids, but its yield has been difficult to improve. The hybridization between the indica and japonica subspecies has stronger heterosis; the utilization of inter-subspecies heterosis is important for long-term improvement of rice yields. However, the different diurnal flower-opening times (DFOTs) between the indica and japonica subspecies seriously reduce the efficiency of cross-pollination and yield and increase the cost of indica–japonica hybrid rice seeds, which has become one of the main constraints for the development of indica–japonica hybrid rice breeding. The DFOT of plants is adapted to their growing environment and is also closely related to species stability and evolution. Herein, we review the structure and physiological basis of rice flower opening, the factors that affect DFOT, and the progress of cloning and characterization of DFOT genes in rice. We also analyze the problems in the study of DFOT and provide corresponding suggestions.

Genome-wide association study reveals markers and candidate genes associated with growth in the rice flower carp, an economic fish species of integrated rice-fish culture in China

The rice flower carp (Cyprinus carpio) is an important fish in integrated rice-fishery farming. Here, we performed the first genome-wide association study (GWAS) for seven growth traits (including body mass, total length, body length, body height, body width, caudal-peduncle depth, and eye spacing) in 200 rice flower carp samples using 369,688 high-quality SNPs and 42,225 indels obtained by double-digest genotyping-by-sequencing (ddGBS). The morphometrics of these traits were highly correlated (Pearson’s correlation coefficients = 0.74–0.99, p &amp;lt; 0.001). GWAS detected 15, 5, 4, 26, 7, 16, and 17 loci significant associated (-log10P ≥ 5) with body mass, total length, body length, body width, body height, caudal-peduncle depth, and eye spacing, respectively. Subsequently, within the 50 kb upstream and downstream regions surrounding these significant loci, 38, 19, 18, 20, 52, 27, and 37 candidate genes for the seven growth traits were detected, respectively. Importantly, B6_4352672 and A8_4978825 were significantly associated with more than five growth traits. These results showed loci significantly associated with more than five growth traits will be helpful for future marker-assisted selection (MAS). Interestingly, chromosomes A8 and B25 had many loci significantly associated with growth traits, most of which were shared among multiple growth-related traits. These results indicated that chromosome A8 and B25 may be closely related to growth traits. Our findings not only help understand the genetic architecture of growth traits in fish but facilitate the identification of candidate genes for marker-assisted selection towards breeding faster-growing rice flower carp in the future.

Overproduction of OsRACK1A, an effector-targeted scaffold protein promoting OsRBOHB-mediated ROS production, confers rice floral resistance to false smut disease without yield penalty

Grain formation is fundamental for crop yield but is vulnerable to abiotic and biotic stresses. Rice grain production is threatened by the false smut fungus Ustilaginoidea virens, which specifically infects rice floral organs, disrupting fertilization and seed formation. However, little is known about the molecular mechanisms of the U. virens–rice interaction and the genetic basis of floral resistance. Here, we report that U. virens secretes a cytoplasmic effector, UvCBP1, to facilitate infection of rice flowers. Mechanistically, UvCBP1 interacts with the rice scaffold protein OsRACK1A and competes its interaction with the reduced nicotinamide adenine dinucleotide phosphate oxidase OsRBOHB, leading to inhibition of reactive oxygen species (ROS) production. Although the analysis of natural variation revealed no OsRACK1A variants that could avoid being targeted by UvCBP1, expression levels of OsRACK1A are correlated with field resistance against U. virens in rice germplasm. Overproduction of OsRACK1A restores the OsRACK1A–OsRBOHB association and promotes OsRBOHB phosphorylation to enhance ROS production, conferring rice floral resistance to U. virens without yield penalty. Taken together, our findings reveal a new pathogenic mechanism mediated by an essential effector from a flower-specific pathogen and provide a valuable genetic resource for balancing disease resistance and crop yield.

Transcriptome analysis reveals the involvement of ubiquitin-proteasome pathway in the regulation of muscle growth of rice flower carp

Growth mechanism of economically important aquaculture species has aroused widespread interest among scholars. Rice flower carp (Cyprinus carpio), commonly cultured in rice-fish farming systems, shows wide variation in body mass at the same age, which limits the development of commercial aquaculture. In this study, muscle tissues from 20-month-old fish of different sizes were used for transcriptome analysis and muscle histological studies. The muscle histological analysis showed the muscle growth in rice flower carp main depends on the hypertrophic growth of muscle fibers. A total of 30,590 unigenes were generated by muscle trancriptome analysis, including 403 differentially expressed genes (DEGs). Of these, 157 DEGs were upregulated and 246 DEGs were downregulated. Nine unigenes related to the ubiquitin-proteasome pathway were identified using differential expression analysis. This study initially revealed that the differences in growth of rice flower carp could be due to hypertrophic growth of muscle fibers caused by higher protein deposition, and the ubiquitin-proteasome pathway was an important factor affecting the growth rate of rice flower carp. E3 ubiquitin-protein ligase ari7, g2e3, Neurl1 and rnf144ab were upregulated in the slow-growing fish, indicating the binding of ubiquitin to target protein was enhanced. Foxo3 was upregulated in the slow-growing fish, which could promote the muscle loss. Eif4a2 was upregulated in the fast-growing fish, increasing protein translation efficiency. Some genes related to active muscle contraction such as actb, actg, camk2a, and camk2b were upregulated in the fast-growing rice flower carp muscle. In summary, these results provide valuable information about the key genes for use as biomarkers of growth in selective breeding programs for rice flower carp and provide novel insights into the regulatory mechanisms of muscle growth.