The total RNA of Aquilaria sinensis vitro roots was extracted using the EASYspin Plus Plant Rapid Extraction Kit after three consecutive generations of salt stress treatment, and sequenced using the HiSeq 2500 high- throughput sequencing platform, aiming at exploring the roles of miRNAs in the three generations of A. sinensis vitro roots under salt stress and the metabolic pathways that may be involved in the regulation, and providing references to reveal the mechanisms of A. sinensis. The miRNA expression profiles of the first, second and third generations were obtained by using the high-throughput sequencing platform and bioinformatics technology, and the differential miRNAs in the three generations of vitro roots were screened, and the target genes of the differential miRNAs were predicted, and then the target gene analysis was performed to obtain the miRNAs that might be involved in the secondary metabolites of A. sinensis and those that were related to the response to salt stress. The results showed that 508 known miRNAs and 764 new predicted miRNAs were detected in the first-generation samples; 444 known miRNAs and 673 new predicted miRNAs were detected in the second-generation samples; 904 known miRNAs and 1100 new predicted miRNAs were detected in the third-generation samples. A total of 59 differentially expressed miRNAs and 275 target genes were obtained from the three samples. The up-regulated miRNA target genes were mainly involved in flavonoid biosynthesis and glutathione metabolism, while the down-regulated miRNA target genes were mainly involved in phenylpropanoid biosynthesis, Plant hormone signal transduction, plant-pathogen interactions and other signaling pathways. The key miRNAs were selected for NR annotation, and it was found that miR8020-x and novel-m0628-5p might be involved in the synthesis of secondary metabolites in A. sinensis vitro roots, and miR7494-y, miR477-y, miR5185-y, miR7757-y, miR408-z, and novel-m0628-5p might be responded to A. sinensis vitro roots salt stress. In this study, we used high-throughput sequencing to obtain miRNA expression profiles of A. sinensis vitro roots under salt stress, and bioinformatics analysis to obtain miRNAs that may be involved in secondary metabolites of A. sinensis and those related to the response to salt stress. The results of the present study will help to enhance the understanding of the miRNA regulatory mechanisms of A. sinensis under salt stress conditions and provide a new pathway for the synthesis of secondary metabolites of A. sinensis.

Mulberry is a fruit tree with rich nutrition and dual functions of food and medicine, which is deeply loved by consumers. The fragrance is a significant factor in the sensory quality of mulberries, playing a crucial role in consumer purchasing behavior. Mulberry Baichang is a unique variety that emits a strong, creamy fragrance, which has enormous potential market value. However, the key metabolites and mechanisms responsible for the formation of this fragrance are still unclear. In this study, we utilized GC-MS and RNA-seq technology to examine the volatile organic compounds (VOCs) and gene expression in Baichang and Hongchang, which lacking a distinct fragrance. The results showed that 661 volatile metabolites were detected in both varieties. Most of these were found in higher relative amounts in Baichang, with 47 types being present only in Baichang, suggesting a rich composition of VOCs in this variety. A total of 312 metabolites were identified as differential metabolites; combining the sensory annotation information and relative content of VOCs, 70 candidate VOCs were annotated as being related to the formation of “sweet, waxy, coconut and oily” sensations. These could potentially be the key metabolites contributing to the unique aroma of Baichang. The relative odor activity value (rOAV) analysis revealed that 5-hexyldihydro-2(3H)-furanone (also known as γ-decalactone) was the key VOC contributing to the formation of the special aroma of Baichang. Using RNA-seq, 19 key structural genes related to ester synthesis were screened, including AAT, ACX, ALDH, CYP, EHL, FAD, HPL and LOX. The high expression levels of these structural genes in Baichang may contribute to the unique creamy aroma of this variety; however, the underlying mechanisms require further investigation. This study would provide insights into the aroma differences among different kinds of mulberries.

In order to select a new tobacco variety with excellent industrial and agricultural characteristics was selected, the tobacco variety Y87 was used as the control to compare and analyze the agronomic traits, ultrastructure, metabolites and post baking tobacco quality evaluation of four newly introduced tobacco varieties Y121, Y116, Y301 and Y119. The results showed that Y121 had relatively good field growth, complete chloroplast structure, and a large volume and quantity of osmium loving particles on the chloroplast membrane. Through metabolic pathway enrichment analysis, it was found that Y121 contained more organic acids such as succinic acid and phenylacetic acid, as well as fewer nicotine such as nicotine reducing and new tobacco alkaloids, which are beneficial for improving the aroma quality and safety of tobacco leaves. In addition, compared to other newly introduced varieties, the Y121 had better appearance quality, more coordinated chemical composition, higher sensory quality score, and is closer to Y87. The results would provide reliable technical support for the upgrading of varieties, which is conducive to the sustained and stable development of high-quality raw material production.

Biomass is a key factor in plant evolutionary adaptation and yield, and obtaining high-yield crop varieties is always a basic requirement for crop breeding. In this study, a mutant Mu with increased biomass was discovered during the tissue culture of Setaria viridis ME34, and the trait can be stably inherited to the next generation. Through the observation of the phenotype of S. viridis and statistical analysis of the agronomic traits of seedlings and adults, it was found that the biomass (fresh and dry weight) of the mutant seedlings and the adult plant height of S. viridis mutant was significantly higher than that of the wild-type plants, and the spike length and seed length were also significantly longer than those of the S. viridis wild-type plants, reaching a highly significant level. Transcriptome sequencing was performed on the leaves and stems of ME34 and Mu, and some genes were validated by RT-PCR. Differential expression gene analysis revealed that the genes related to nitrogen metabolism and regulation accounted for about 20% of the total differential genes. GO functional and KEGG enrichment analysis also revealed a close relationship between biomass and nitrogen metabolism and regulation. The DEGseq method was used to analyze the changes in the differentially expressed genes, and some related genes involved in nitrogen absorption, transport, assimilation, and reuse were obtained, such as nitrate transporter NRT, ammonium transporter AMT, nitrate reductase NR, nitrite reductase NiR, glutamate synthase GOGAT, NLP family transcription factors, and serine threonine protein kinase. Through the above research, important molecular basis and foundation are provided for the breeding work of crops such as foxtail millet.

Camellia oleifera is a significant woody oil tree species that is extensively cultivated in southern China. It displays a notable degree of diversity in phenotypic traits, such as fruit, leaf and tree shapes, etc.. In the present study, 100 C. oleifera seedling trees were collected and 33 phenotypic traits were subjected to the comprehensive evaluation. In the diversity analysis of quantitative traits, the coefficient of variation (CV) was ranged from 8.81% to 56.85%, with the number of flowers per unit area (NFPUA) exhibiting the greatest variability (56.85%), and the fruit shape index (FSI) demonstrated the least variability (8.81%). The diversity index of quantitative traits exhibited a range of 1.13 to 4.61, indicating a notable degree of genetic diversity in fruit and leaf traits. Cluster analysis classified the 100 germplasm accessions into five categories. The first category was characterized by dark fruit colour, a rounder fruit shape, and taller trees. The second category exhibited flattened fruit shape and heavier fruit weight with narrower tree cannopy. The third category was characterized by longer fruit shapes with heaviest single fruit weight, and smaller but denser tree canopies. The fourth category was distinguished by mainly round fruits, lighter single fruit weight, and larger leaf area. The fifth category exhibited elongated fruits with thicker peels and more opened tree canopy. Principal component analysis yielded 12 principal components, collectively accounted for 79.174% of the cumulative contribution rate, including traits such as fruit diameter, single fruit weight, and fresh seed weight. Based on the results of the principal component analysis, superior C. oleifera accessions were selected for further observation. This study demonstrated that C. oleifera germplasm resources in Hainan province exhibited a high level of phenotypic trait diversity. The research would provide a theoretical base for the genetic improvement of C. oleifera.

Based on 24 phenotypic traits, statistical analysis, correlation analysis, principal component analysis and systematic cluster analysis were carried out on 187 pepper hybrid combinations introduced from different ecological regions in China to screen out the best hybrid combinations of pepper suitable for planting in Jiangxi. The Shannon-Weaver genetic diversity index of 12 descriptive traits was ranged from 0.36 to 1.95, with an average of 0.82. The genetic diversity index of fruit shape was highest (1.95). The variation coefficient of 12 quantitative traits was ranged from 16.61% to 84.48%, and the variation coefficient of single fruit weight was the largest. The genetic diversity index was ranged from 0.67 to 2.08, with an average of 1.80. Correlation analysis showed that the correlation coefficient (r_s) between single fruit weight and fruit diameter was the highest, reaching 0.86. In addition, yield was significantly positively correlated with fruit diameter, fruit flesh thickness and single fruit weight. Principal component analysis simplified the 24 traits index into 3 principal components, and the cumulative contribution rate reached 69.164%. The cluster analysis showed that the 187 hybrid combinations could be divided into 5 groups at 8.10 Euclidean-distance, and there were significant differences in single fruit weight, fruit color, fruit shape and plant height among the groups. After comprehensive scoring, 10 excellent hybrid combinations suitable for planting in Jiangxi were selected. The above results would provide scientific basis for the comprehensive evaluation, selection and application of pepper hybrid combination.

To generate polyploid B. ochracea Schltr and find out the optimal induction condition, the seeds of diploid B. ochracea were treated with different concentration of colchicine solution under a range of treatment time. The results of the study suggested that the seeds treated with 0.25% colchicine solution for six days was effective in polyploid induction for B. ochracea, with a 35.66% survival rate of treated seeds and a 45% induction rate. The tetraploid gave a significant enhancement on various agronomic traits, including plant height, leaf number, leaf width, stem diameter, bulb length and root diameter. In addition, tetraploid B. ochracea showed increased stomatal aperture and decreased stomatal density. The tetraploid B. ochracea was generated in this study, which would provide technical support and basic material for improving the genetic traits of medicinal orchids.

Longan (Dimocarpus longan Lour.) is an important economic crop in tropical subtropical areas. Under normal circumstances, longan can become flowers only when induced by low temperature in winter together with appropriate measures to control the winter tips, but potassium chlorate, as the only known compound that can induce longan to become flowers in the opposite season, the anatomical process and physiological mechanism of the potassium chlorate-regulated flower formation are not clear, and the carbon and nitrogen nutrition is closely related to flower formation. Carbon and nitrogen nutrition are closely related to flower formation, therefore, analyzing the changes of carbon and nitrogen content of longan by potassium chlorate is also an important perspective to reveal the mechanism of flower formation. In this study, we used Shixia longan (Dimocarpus longan Shixia) as the test material, and induced the antiseasonal flower formation of longan by soil application of potassium chlorate to investigate the anatomical changes of the terminal buds of the antiseasonal longan during flower formation, and analyzed the changes in the C and N contents as well as the relationship between C/N and the development of the terminal buds. By observing the growth point of the terminal buds in the control group, which always showed a more pointed leaf bud state, the terminal buds after potassium chlorate treatment clarified the three stages of flower bud differentiation according to the changes in the morphology of the growth point: the stage of physiological differentiation of flower buds, the stage of inflorescence formation of flower buds, and the stage of floral organ formation. The carbon content of terminal buds treated with potassium chlorate showed a continuous increasing trend, while the carbon content of the control showed an increasing and then decreasing trend, the nitrogen content of both groups showed an increasing and then decreasing trend, and the C/N trend of the two groups showed a “stable-decreasing-increasing” trend. At the stage of flower bud physiological differentiation, the C/N content of terminal buds increased more than that of the control after KClO₃ treatment, while the N content of both groups did not change much. The C/N content of terminal buds increased from 22.82 to 23.41, while that of the control decreased from 22.82 to 22.63, showing a smooth trend in both groups. During the inflorescence formation stage of flower buds, the increase in total carbon content of terminal buds was smaller than that of the control, while the increase in total nitrogen content was larger than that of the control after potassium chlorate treatment; the C/N of terminal buds decreased from 23.41 to 17.65 after potassium chlorate treatment, while that of the control decreased from 22.63 to 20.29, and the decrease of terminal buds was larger after potassium chlorate treatment than that of the control. At the stage of inflorescence emergence, the whole carbon and nitrogen contents of terminal buds showed an increasing trend after potassium chlorate treatment, while the opposite was true for the control. The C/N of terminal buds increased from 17.65 to 21.44 after potassium chlorate treatment, while that of the control increased from 20.29 to 22.92, but the rate of increase of terminal buds was greater after potassium chlorate treatment than that of the control. This study reveals that a more than 21.47% increase in the C/N ratio of longan terminal buds is conducive to flowering. The application of potassium chlorate through soil leads to a continuous increase in total carbon content and an initial increase followed by a decrease in total nitrogen content in longan terminal buds, resulting in a significant rise in the C/N ratio, which is beneficial for the development of terminal buds towards floral formation.

Guangxi is the leading sugarcane production area in China. over 85% of the sugarcane is planted on non-irrigated dry land, and varying degrees of drought damage occur every year. Drought is the main limiting factor for sugarcane production in China. Tillering is one of the important traits affecting the yield of sugarcane. It is of great significance to study the effect of drought stress on the development of tillering buds at tillering stage. Guire 2 is a new sugarcane variety bred by our team with good drought resistance and strong tillering ability. In order to investigate the effects of drought stress on physiological indicators of sugarcane tillering seedlings and leaves at tillering stage, Guire 2 was used to conduct drought stress experiments at the early stage of sugarcane tillering. The experiment was set up with control (19%-25% soil absolute water content) and drought stress treatment by stopping irrigation. Samples were taken from the control group and treatment group at early drought stress (14%-15% soil absolute water content), middle drought stress (10%-11% soil absolute water content), late drought stress (6%-7% soil absolute water content) stages. The changes of antioxidant enzyme activity, MDA, osmoregulatory substances and endogenous hormone contents were measured by subordination function method. The correlation of the physiological indicators in sugarcane tiller shoots and leaves was analyzed, and the drought resistance of tiller shoots and leaves was evaluated. The results showed that drought stress increased the activities of peroxidase (POD), and superoxidate dismutase (SOD), and contents of proline (Pro), soluble protein, starch, sucrose and abscisic acid (ABA), especially in tiller shoots, the treatment group and the control group reached a significant difference, while the malondialdehyde (MDA) content remained at a similar level in sugarcane tillering seedlings and leaves during drought stress. Compared with leaves, drought stress significantly increased the activity of SOD and the contents of Pro, soluble protein and sucrose in tiller shoots. Correlation analysis showed that most significant correlations between the physiological indicators in sugarcane tiller shoots and leaves under drought stress were positive, and sucrose content, starch content, Pro content, IAA content and SOD activity were more significantly or extremely significantly correlated with other indicators. According to the comprehensive drought resistance coefficient and the average of subordinate function values of each index, the drought resistance of tiller shoots was stronger than that of leaves in sugarcane.

Lodging was one of the important limiting factors for high yield, high sugar content and mechanized harvesting of sugarcane, and it was also an urgent problem to be solved in sugarcane mechanized breeding. In this study, 24 reciprocal hybrids of 57NG208 and Nanjian chewing cane and PT43-52 (CK) were used as research materials. The plant height, basal stem diameter, middle stem diameter, brix, center of gravity height, single stem weight, the lodging resistance index, basal and middle stem diameter ratio and stem breaking force were measured. The correlation analysis, principal component analysis, membership function method and cluster analysis were used to comprehensively evaluate them. The results showed that the coefficient of variation of 9 indexes such as lodging resistance index and agronomic traits of 25 materials was between 11.57% and 30.80%, and the traits were obviously separated and the variation was abundant. The correlation analysis showed that the lodging resistance index was significantly positively correlated with brix, basal stem diameter, basal and middle stem diameter ratio, center of gravity height, single stem weight and stem breaking force, and negatively correlated with plant height and middle stem diameter. The results of principal component analysis showed that the cumulative contribution rate of the first three principal components was 75.7717%, which represented most of the information of lodging resistance of the tested materials. Cluster analysis showed that 25 materials could be clustered into three categories, and the results were consistent with the results of membership function evaluation. Among them, 13 materials in the first category had excellent lodging resistance and high comprehensive evaluation scores, especially Yunrui 12-9-45, Yunrui 12-9-5, Yunrui 12-38-32, PT43-52 and Yunrui 12-38-46. The lodging resistance index of the remaining germplasms was 3.00 except Yunrui 12-38-46, and the comprehensive evaluation E value was in the top 5, which should be used in the future improvement of lodging resistance.