The study was aimed to analyze the genetic diversity of the phenotypic traits and chemotypes of different Ocimum basilicum germplasm resources, to provide theoretical reference for the innovative utilization of basil germplasm resources and variety selection. The botanical traits of 15 basil germplasm resources and the volatile components of the leaves investigated and determined using gas chromatography-mass spectrometry (GC-MS), together with the relative odour activity values (ROAV). At the same time, principal component analysis and cluster analysis were carried out on the tested germplasms. The 15 basil germplasms differed significantly in plant height, plant width, leaf length, leaf width and stem thickness, except for the number of branches. 104 volatile compounds were identified, including 37 alkanes, 32 terpenes, 8 esters, 5 phenols, 4 alcohols, 3 aldehydes, 1 ether, and 14 other compounds, of which there are two types of common components, 2,4-di-tert-butylphenol and heptadecane. According to the ROAV values obtained from the enquiries and calculations, the key aroma substances were found to be eugenol, linalool, eucalyptol, cis-citral, methyl cinnamate, 4-allyl anisole, etc. The principal component analysis and cluster analysis of the volatile substances the germplasms could be classified into five groups, namely, Thai basil, Anise basil, Siam queen basil and Sweet basil were grouped together, Jiu Cengta basil, Genovese basil, Red rubin basil, Purple dark opal basil and Purple ruffles basil were grouped together, Clove basil and Lemon basil were grouped together, Tuscany basil, Pluto basil and Italian large leaf basil were grouped together, Cinnamon basil was grouped one category. The phenotypic trait cluster analysis also classified basil into five groups, with Pluto basil into a group, Clove basil, Anise basil and Purple dark opal basil into a group, Thai basil into a group, Italian large leaf basill and Cinnamon basil into a group. The remaining eight germplasm were clustered into a group. The 15 germplasms have significant differences in botanical characters and volatile components, and are rich in genetic diversity, which could be targeted for breeding of basil-specific germplasms.

Tobacco is an important economic crop, and its leaves have great economic value. In recent years, with the increase of tobacco planting areas, the varieties of leaf diseases are on the rise. Two strains of tobacco leaf spot disease pathogenic bacteria were isolated from the tobacco leaf disease samples in Hezhou, Guangxi. Through polygenic phylogenetic analysis, they were identified as Cumuliphoma indica, which is the first report on the tobacco leaf spot disease caused by C. indica in China. To clarify the biological characteristics of the pathogen and screen the control agents, this study used the mycelial growth rate method to study the lethal temperature of the mycelia of the strain, and its growth in different media, temperatures, pH, carbon sources, nitrogen sources, light cycles and to determine the sensitivity of the pathogen to nine chemical agents. The biological characteristics showed that the temperature range of C. indica mycelium growth was wide, and the optimum temperature was 28 ℃. Weak acid environment was more favorable for mycelium growth, and the optimal pH was 5. It grew fastest on CMA and CDA. The optimum nitrogen source was peptone. The optimum carbon sources was soluble starch. The lethal temperature of mycelium was 49 ℃, and the water bath was 10 min. Light had a significant effect on the growth of the mycelia, and 24 h full light was the most favorable. The results of laboratory screening showed that the nine tested fungicides had different inhibition on the growth of C. indica mycelia, among which boscalid 50% WG had the best inhibitory effect, EC₅₀ was 0.025 mg/L. The second was fludioxonil 50% FS (0.084 mg/L), iprodione 500 g/L SC (0.217 mg/L), prochloraz 450 g/L EW (1.354 mg/L), mancozeb 80% WP (6.565 mg/L), difenoxazole 10% ME (9.576 mg/L), pyraclostrobin 25% SC (34.237 mg/L) and myclobutanil 40% SC (38.804 mg/L). The inhibitory effect of tebuconazole 430 g/L SC was the weakest, EC₅₀ was 42.574 mg/L. The study revealed the biological characteristics of C. indica for the first time, and recommended 50% acetanilide WG as a candidate fungicide for the prevention and control. The results could provide a reference for the effective prevention and control of tobacco leaf spot disease caused by C. indica.

The yield and quality of sweetpotato root tubers can be significantly improved by applying paclobutrazol (PBZ), and sucrose-degrading enzymes play important roles in the development of storage roots of sweetpotato. However, the physiological and biochemical mechanisms underlying PBZ-regulated storage root development is still unclear, and especially it remains to be investigated whether sucrose metabolism is involved in the PBZ-regulated development of storage roots. In this paper, sweetpotato cultivar Kokei 14 was used, a predominant cultivar planting in Hainan. After applying PBZ treatment in the early stage of cultivation (20-30 d after planting, dap), the following phenotypic parameters were investigated at 120 dap including the fresh weight of storage root per plant, fresh weight per storage root and storage root number per plant. To elucidate the physiological and biochemical mechanisms relevant to sucrose metabolism underlying PBZ-regulated storage root development, the following physiological and molecular parameters were also examined in storage roots at different development stages (30, 60, 90 and 120 dap) including the content of starch and soluble sugars (glucose, fructose and sucrose), the activities of sucrose-degrading enzymes and expression levels of the gene families. PBZ increased the yield of sweetpotato by increasing the fresh weight per storage root, but without affecting storage root number per plant. PBZ increased the content of soluble sugar and starch in storage root. However, the effect of PBZ on the yield and quality of storage roots only occurred in the early stage (30-60 d after planting) after treatment, and in the late stage (90-120 d), PBZ treatment had no significant effect on yield and quality. PBZ treatment significantly increased the activities of sucrose synthase (Sus), cell wall invertase (CWIN) and cytoplasmic invertase (CIN). However, PBZ had no significant effects on vacuolar invertase (VIN). As compared to CWIN and CIN, Sus activity was induced by PBZ treatment much earlier and more dramatic. Sus activity was significantly induced at 30 dap, whereas the activity of CWIN and CIN were significantly induced at late stage i.e. 60 dap. In other periods (especially 90-120 d), PBZ treatment had no significant effect on the activities of Sus, CWIN and CIN. The determination of the expression level of Sus, CWIN and CIN genes showed that IbSus2, IbSus5-7 and IbSus9 highly expressed in storage tuber were all significantly induced by PBZ at 30 dap. IbCIN3, IbCIN7 and IbCIN8 expressed in storage roots, and IbCWIN2 and IbCWIN4 expressed in storage roots were significantly induced by PBZ at 60 dap. However, in other periods (especially 90-120 d), PBZ treatment had no significant effect on the expression level of the relevant genes. It is speculated that the increase of Sus expression and activity under PBZ treatment is earlier and more dramatic, which can promote the rapid and biosynthesis and accumulation of starch and the rapid expansion of storage roots, while the subsequent increase of CWIN and CIN expression and activity can increase the content of soluble sugar in root tubers thus improving the quality of storage roots, and can also provide energy supply for starch biosynthesis and storage root expansion. The specific members of Sus, CWIN and CIN genes induced by PBZ had also been identified. Notably, the effects of PBZ on the yield and quality of storage roots, and activities and gene expression levels of sucros-degarding enzymes in storage roots mainly occurred in the short period after PBZ treatment. With the extension of time, the effects of PBZ on the above indicators gradually disappeared. Therefore, in order to improve the yield of sweetpotato in production, it is necessary to conduct PBZ treatment throughout the entire growth period of sweetpotato. The above results can provide a theoretical basis for achieving high-quality and high-yield sweetpotato production by variety breeding or cultivation measures.

Anacardium occidentalie Linn is a typical tropical fruit tree, which is mainly planted in Yunnan and Hainan provinces of China. Cashew cultivation has important economic, social and ecological values. It is of great value to realize realize the strategy of rural revitalization in China, increase farmers' production and income, and achieve common prosperity. Cashews are very sensitive to low temperatures, and they will be severely damaged at 8 ℃and the growth will stop. Therefore, lowtemperature stress is an important abiotic stress that restricts cashew growth. CBF transcription factors play important roles in plant response to abiotic stresses such as low temperature, drought and salt. However, the role of CBF gene family in cashews has not been elucidated, and the expression pattern of this family in response to low temperature stress is unknown. In this study, in order to explore the basic characteristics of the CBF gene family in cashew nuts, six AoCBF gene family transcription factors were identified and obtained from the cashew transcriptome by bioinformatics methods, and the physical and chemical properties, protein structure, phylogeny, promoter action elements and expression patterns under low temperature induction were analyzed. The length of the six AoCBF proteins ranged from 189 to 334 aa, and the molecular weight of the proteins ranged from 21.31 to 37.89 kDa. The isoelectric points of the six AoCBF proteins were less than 7, indicating that the proteins were acidic. The proteins all contained an AP2/ERF domain. Motif analysis showed that there were five motifs in AoCBF genes, and the absence of different AoCBF gene motifs implied the absence of related functions. Phylogenetic tree analysis showed that the six AoCBF genes could be divided into two subgroups, A and B, in which group A contained one gene and group B only contained five genes. The analysis of homeotropic elements of promoter showed that AoCBF gene might be involved in the response to hormone and abiotic stress. Fluorescence quantitative expression analysis showed that all the six AoCBF genes responded to low temperature and cold stress to different degrees, indicating that AoCBF played a role in the biological process of cashew nut in response to low temperature stress. The results summarized the basic characteristics of the AoCBF gene family and accumulated basic data for further molecular resistance research and application of cashews AoCBF genes.

Phosphatidyl ethanolamine-binding protein (PEBP) widely exist in plants and play important roles in regulating flowering, seed dormancy and the formation of underground storage organs (e.g. potato tubers and onion bulbs). However, up to now, there is few studies conducted on PEBP genes in sweet potato (Ipomoea batatas), and there is also no research published to reveal the key members of PEBP gene family that regulate the development of storage root of sweet potato. Our study first identified the number and types of the PEBP gene family in sweet potato through bioinformatics analysis. Then, to screen the candidate members of the PEBP gene family that regulate the development of storage root of sweet potato, the tissue specificity of PEBP gene expression and the dynamic changes of PEBP gene expression level in storage roots at different development stages were analyzed. To explore possible regulatory mechanism, the correlation between PEBP gene expression level and SWEET gene expression level in storage roots were also examined. The results are as follows: (1) A total of 15 putative PEBP genes were identified from the sweet potato genome, which were classified into 4 subfamilies: 5 of FT-like genes (IbFT1-5), 6 of TFL1-like genes (IbTFL1-6), 2 of MFT-like genes (IbMFT1-2), and 2 of PEBP-like genes (IbPEBP1-2). (2) Clustering analysis revealed that IbFT5 may promote the development of storage root of sweet potato, while IbTFL3 may inhibit the development. (3) The tissue specificity analysis of sweet potato PEBP gene expression showed that IbFT5, IbTFL4 and IbTFL6 not only showed higher expression levels in the diverse root tissues than in other tissues, but also had higher expression levels in roots than other PEBP genes. Therefore, it is speculated that the three PEBP genes may promote root enlargement. (4) The expression levels of the four candidate PEBP genes (IbFT5, IbTFL3, IbTFL4 and IbTFL6) obtained from the above two methods were determined in storage roots at different developmental stages (30, 60, 90 and 120 days after planting). It was found that the expression levels of IbFT5, IbTFL4 and IbTFL6 significantly increased with the development of root tubers, especially during the rapid expansion period (60-90 days), while the expression level of IbTFL3 rapidly de-creased during the rapid expansion period (60-90 days). Therefore, all the above measurement results indicate that IbFT5, IbTFL4 and IbTFL6 may promote root development, while IbTFL3 may inhibit root development. (5) With the increase of expression levels of IbFT5, IbTFL4 and IbTFL6, the expression levels of four out of the five highly ex-pressed SWEET genes (IbSWEET4, IbSWEET11, IbSWEET16 and IbSWEET19) in storage roots showed a continuous decreasing trend. This result is similar to the findings in potatoes, indicating that the PEBP gene of sweet potato may also inhibit SWEET activity and thus promotes the transportation of sugar to the storage roots through more efficient symplasmic pathway, which ultimately promotes the development of storage roots. In conclusion, this study not only determined the number and types of members of the PEBP gene family in the sweet potato genome, but also systematically identified four candidate PEBP genes affecting the development of sweet potato storage roots, which can provide a theoretical basis for further improvement of sweet potato yield in China.

The fruit quality of different varieties (lines) of cultivated ginseng fruit in Shilin county was tested and evaluated to provide guidance for the development of ginseng fruit industry. Seven fruit quality indexes of soluble sugar, soluble protein, soluble solid, mineral elements, vitamin C, cellulose and amino acid were determined by using eight main ginseng fruit varieties (lines) of Dayuangguo, Yuangguo No. 1, Yuangguo No. 2, Yuangguo No. 3, Shiyou No. 1, Shiyou No. 2, Shiyou No. 3 and Ruiyu cultivated in the field of Shilin county. By multiple comparison of quality indexes of Panax ginseng fruit, it was found that the content of soluble sugar in Yuanguo No. 2 was the highest, while that in Dayuanguo and Yuanguo No. 3 was the lowest; The soluble protein content of Shiyou No. 2 was the highest, and that of Shiyou No. 1 and Ruiyu was the lowest; The content of soluble solids of Yuanguo No. 2 was the highest, while that of big round fruit was the lowest; Shiyou No. 3 has the highest content of vitamin C and Yuanguo No. 3 has the lowest content; The crude fiber content of Yuanguo No. 2 was the highest, and that of Shiyou No. 1 was the lowest; The content of trace elements in Yuanguo No. 2 was the highest, while that in Yuanguo No. 3 was the lowest; The amino acid content of big round fruit was the highest, and that of Shiyou No. 2 was the lowest. There were significant correlations between the quality indicators of different varieties (lines), among which soluble sugar and soluble solids were significantly correlated with each other (P<0.05). The principal component analysis of 6 quality indicators was carried out, and the cumulative contribution of the first three principal components reached 83.955%, which could reflect most of the information of the original quality index. The resulting comprehensive evaluation system was established to evaluate eight different varieties (lines) of ginseng fruit. In conclusion, the above eight ginseng fruit varieties (lines) all contain rich nutritional components, among which Yuanguo No. 2 has the best comprehensive quality, and can be selected as the parent material for the main variety or new germplasm creation.

Dendrobium kingianum belongs to Orchidaceae family, which is widely grown as an ornamental plant in China. In recent years, a blight disease in D. kingianum is observed in Guangdong province, China. This disease infects the stems and leaves of D. kingianum, causing brown rot and plant death. It has a serious impact on production. A fungus was isolated from the diseased plants of D. kingianum. The pathogenicity test showed that this fungus could infect healthy potted plants and cause the disease. The symptoms on inoculated plants were similar to field symptoms. Morphological characteristics of the fungus from the inoculated plants were consistent with that of the original fungus from field samples. The pathogen was identified by both morphological characteristics and β-tubulin (tub) gene sequence analysis. The morphological characteristics of the isolates were similar to Phytophthora palmivora. BLAST results showed both the sequences of two isolates in this study were 99% identical to the sequence of P. palmivora. In the maximum likelihood (ML) tree based on tub gene sequences, the strains in this study clustered with P. palmivora with 100% support. Therefore, P. palmivora was identified as the pathogen of Phytophthora blight on D. kingianum based on morphological characteristics and phylogenetic analysis. This is the first report of P. palmivora causing Phytophthora blight on D. kingianum in China and worldwide. The inhibitory effect of 10 fungicides on P. palmivora was determined using the mycelial growth rate method. The results showed that four fungicides, namely diacetylomyamide, dimethomorph, metalazepine and metalazepine · mancozeb, were the top four toxic to P. palmivora, and the EC₅₀ value was 0.000 03 μg/mL, 0.0628 μg/mL, 0.2381 μg/mL and 0.5457 μg/mL, respectively. It was followed by chlorothalonil, pyrimethole and mancozeb, the EC₅₀ was less than 10 μg/mL. However, the effect of downy mildew hydrochloride and triethylphosphonate was poor, and the EC₅₀ was more than 100 μg/mL. Carbendazim showed no inhibitory effect, the EC₅₀ was more than 1000 μg/mL. The result would provide a theoretical basis for the prevention and control of Phytophthora blight in Dendrobium.

The heat shock transcription factor MeHsfB3b is important in regulating the resistance to cassava bacterial blight. In the previous study, the candidate interaction protein MeFKBP20 of MeHsfB3b was obtained by the yeast two-hybrid technology, which belongs to the FKBP-type peptide prolyl cis-trans isomerase gene family. In this study, the full-length MeFKBP20 gene was cloned to be 561 bp, encoding 186 amino acids, with a molecular weight of 19.99 kDa and a FKPB_C domain. The expression pattern analysis showed that MeFKBP20 was highly expressed in mature leaves and roots of cassava, and the expression level of young leaves and petioles was low. It could quickly respond to the in-duction of pathogen XpmCHN11 and maintain a high expression abundance, suggesting that it is involved in response to pathogen infection. The interaction between MeHsfB3b protein and MeFKBP20 protein through 201-241 aa region was proved by the yeast two-hybrid point-to-point and bimolecular fluorescence complementation experiments. The results of this study are helpful to further analyze the mechanism of MeHsfB3b gene regulating cassava resistance to cassava bacterial blight.

In order to understand the dynamic changes of leaf mineral elements in different key seasonal periods of Sapindus Yuanhua clonal raw material forests, and to reveal the characteristics of nutrient demand of this clonal lineage, we provided a theoretical basis for the scientific development of nutrient management system. The 5 a, 6 a and 7 a years old Sapindus Yuanhua clonal forests in Jianning county, Fujian province were used for the study, and the contents of N, P, K, Ca, S, Mg, Fe, Zn and B were measured at the leaf development stage, the end of inflorescence, the end of anthesis, the beginning of fruit expansion, the fruit color change stage and the fruit ripening stage. The contents of N, P, K, Ca and Mg in the leaves of Yuanhua clonal forest showed a general trend of decreasing, then increasing and then decreasing in different critical periods, and all of them reached the highest in the early stage of fruit expansion. There were significant differences in the contents of N and P in the end of inflorescence and the early stage of fruit expansion. K content at the beginning of fruit expansion was significantly higher than the other key reproductive periods, and there was no significant difference between the rest of the reproductive periods, while Ca content and Mg content were significantly different between the leaf expansion period and the beginning of fruit expansion (P<0.05). Fe and B content showed a tendency of increasing and then decreasing, with Fe content being significantly higher than that of the rest of the reproductive periods during the fruit color change period and B content decreasing dramatically at the end of the flowering period, and being significantly lower than that of the rest of the reproductive periods (P<0.05). Zn and S contents did not change significantly throughout the year. The N, K, P and Mg contents of leaves in the three stand ages were significantly and positively correlated. Ca, K and Fe contents were significantly and positively correlated. S and Zn contents were significantly and negatively correlated, and Zn content was significantly and negatively correlated with S and B contents, respectively. The fruit-sitting period (June to the end of July) can be a suitable period for leaf nutritional diagnosis. Fertilizer application should consider the correlation between elements. At the end of inflorescence extraction, N, P and B fertilizers should be applied early. In the fruit-sitting period, an appropriate amount of fertilizer should be applied, combined with the application of micronutrient fertilizer at the same time.

To study the characteristics of free amino acids in wampee, the scientific evaluation of the effects of free amino acids in different wampee germplasm on fruit flavor and medicinal value, the contents of 20 common free amino acids were determined using HPLC with the pulp of 20 wampee germplasms. By using taste activity values, principal component analysis and cluster analysis were used to comprehensively evaluate each wampee germplasm. The results showed that the pulp contained 18 kinds of free amino acids except Cys and Arg. The content was significantly different among major wampee germplasm. The mass concentration of total free amino acids of the 20 wampee germplasms ranged from 1309.7 to 9832.0 mg/kg, among which the content of non-essential amino acids was the highest, the content of essential amino acids was the second, and the content of essential amino acid for children was the lowest. And the content of medicinal amino acids ranged from 6.3% to 18.6% of the total free amino acids, of which Asp and Glu were the major components. According to the different flavor characteristics of amino acids, 18 amino acids were divided into three categories of flavor amino acids, and found that M1 had the highest content of sweet amino acids, and G2 had the highest content of delicious and bitter amino acids. And the TAV of Ala in 16 wampee germplasm resources and Asp and Asn in a few wampee germplasm resources was greater than 1, which contributed to the flavor of wampee. Most free amino acid showed significant or highly significant positive relationships. Meanwhile, four principal components were extracted by principal component analysis, and the cumulative contribution reached 89.766%, which could better reflect the comprehensive characteristics of free amino acids of pulp. In general, the overall scores of each wampee germplasm ranged from –3.18 to 3.51, with M1 having the highest overall score. The 20 wampee germplasms were then clustered into three major groups by clustering analysis, among which X2, Y-1, G2 and M1 of group Ⅲ had high contents of total free amino acids, medicinal amino acids and flavor amino acids, with good amino acid nutritional quality and flavor quality. The results could provide some reference for superior seed breeding and quality evaluation.