Oncidium is an important fresh-cut flower in the market because of its unique flower pattern and brilliant color. The petals of Oncidium are highly susceptible to flower diversity. RNA extraction and transcriptome analysis were performed on the lateral petals of O. flexuosum ‘Honey Angel’ and variants with two lateral petals converted into lips to explore the molecular mechanism regulating the labialization of Oncidium lateral petals. A total of 45 525 415 high-quality reads were obtained from the sequencing results and 52 253 unigenes were identified. The seven databases of NR, Swissprot, PFAM, GO, NT, KO and KOG were used to annotate gene functions and annotated to 31 828, 23 174, 21 369, 21 367, 20 830, 10 523, 6465 unigenes. Upon expression comparison,3120 differential genes were obtained between O. flexuosum ‘Honey Angel’ and the mutant. A total of 1537 differentially expressed genes were annotated into three functional groups: biological processes, cellular components and molecular functions. KEGG functional enrichment analysis enriched 690 differentially expressed genes into different metabolic pathways, with the most genes enriched by metabolic pathway. To date, the study of lip formation in orchids has focused more on the MADS-box gene family, not only five significantly differentially expressed MADS-box genes were screened in this transcriptome data, but also other transcription factor such as NAC, TCP, MYB and WRKY that may be related to the lip formation in Oncidium were also discovered. RT-qPCR was used to verify the expression of key genes, and the quantitative results were consistent with RNA-seq data, most of the genes were highly expressed in the lip-like lateral petals, indicating that the genes may positively regulate the development of the lip of Oncidium. In summary, this study excavated a large number of key transcription factors involved in the variation of labialization in Oncidium, which would provide a certain reference for the study of the molecular mechanism and regulatory network of lip formation of orchid.

Tigernut (Cyperus esculentus L.), which belongs to the Cyperaceae family within Poales, is a novel herbaceous oil crop producing high amounts of oil in underground tubers. Like other tuber and tuberous root crops, water accounts for approximately 85% of immature tubers, implying a crucial role of water balance for tuber development in tigernut. Plasma membrane intrinsic proteins (PIPs), which include two groups (i.e. PIP1 and PIP2) typically localized to the cell membrane, constitute a subfamily of aquaporin facilitating the passive transport of water. Based on one PIP identified in the proteomes of tigernut tubers, its coding gene CePIP1;1 was cloned using the RT-PCR technique, followed by analyzing the exon-intron structure, sequence features, evolutionary relationships, expression profiles, and protein subcellular localization. CePIP1;1 was shown to contain three introns with a coding sequence of 867 bp, putatively encoding 288 amino acids with the theoretical molecular weight of 30.76 kDa, the isoelectric point of 8.82, the instability index of 32.95, the grand average of hydropathicity of 0.384, and the aliphatic index of 95.28, implying that it is stable, basic, and hydrophobic. The protein was predicted to harbor one conserved MIP (major intrinsic protein) domain, including six transmembrane helices, two half helices, and dual NPA motifs located at the N-termini of two half helices. Sequence alignment and phylogenetic analysis revealed that CePIP1;1 clustered with Oryza sativa PIP1s and possesses an extended N-terminus but a short C-terminus relative to Spinacia oleracea PIP2;1, supporting its classification. Transient over-expression in Nicotiana benthamiana leaves supported the plasma membrane localization of CePIP1;1, which is consistent with the bioinformatics prediction. Further expression analysis showed that CePIP1;1 was constitutively expressed in all tissues examined in this study. During tuber development, CePIP1;1 exhibited a typical bell-shaped expression pattern, which is consistent with that of the moisture content. These results lay a solid foundation for further functional analysis and genetic improvement in tigernut.

In this experiment, we analyzed the rhizosphere fungal populations of Aquilaria sinensis (Lour.) Spreng. in different planting areas, and understood the change pattern of the rhizosphere microorganisms before and after agarwood induction, providing a reference basis for the formulation of reasonable cultivation measures for A. sinensis. High-throughput sequencing and bioinformatics methods were used to analyze the diversity and community structure of the rhizosphere soil and fungi of A. sinensis in three sample sites of Hainan province (Wenshan in Haikou, Dongguang in Lingao, and Baolun in Ledong) before and after agarwood induction, the correlation between soil physicochemical properties and fungal communities before and after agarwood induction was also clarified by redundancy analysis. The results indicated that a total of 3 697 288 ITS sequences belonging to 1 kingdom, 2 Phylum, 12 classes, 9 orders, 24 families, 55 genera, 62 species were obtained from the three planting areas. There was little variability in the fungal communities and diversity before and after agarwood induction in the sample plot, but there was significant differences in the abundance of dominant population. The Shannon diversity index of the rhizosphere soil fungi of A. sinensis before and after agarwood induction ranged from high to low: LDWJX>LDJX>LGJX>LGWJX>WSWJX>WSJX. The fungal species composition of the rhizosphere soil samples of A. sinensis was rich. There were differences in the soil fungal community composition, the relative abundance of taxonomic units and the dominant taxonomic units in the rhizosphere of A. sinensis before and after Agarwood induction in different planting areas. In terms of community structure, there were differences in the dominant populations among the three planting areas; at the Phylum level, the common dominant Phyla in the three cultivation areas were Ascomycota and Basidiomycota; at the Class level, the dominant Class in Wenshan was Dothideomycetes, In Lingao the dominant Class was Sordariomycete, In Ledong the dominant Class was Ascomycetes; at the genus level, the dominant genus in Wenshan was p__Ascomycota, in Lingao was Myrothecium, and in Ledong was c__Dothideomycetes. By correlating the physicochemical properties of the inter-rhizosphere soil with the major genera of inter-rhizosphere fungi of A. sinensis in three growing areas, it was found that soil pH, organic matter, alkaline nitrogen, total nitrogen, total phosphorus, effective phosphorus had significant effects on most of the major fungi in the inter-rhizosphere soil of A. sinensis. The results of this study are of guiding significance for the improvement of soil at the fungal level and the evaluation of soil quality of A. sinensis, and also provide a reference basis for the future fertilization strategies of A. sinensis planting areas in Hainan province.

Phosphorus (P) is an essential macro-element for crop growth and is involved in critical physiological and biochemical processes in plants. Pitaya is an important economic crop in tropical and subtropical regions. High fruit P concentration and huge yield require high P demand for pitaya growth. However, the P absorption characteristics of pitaya and the relationship of root morpho-physiological processes and P uptake are still unclear. In this study, pitaya variety Soft Dahong, which is the most popular cultivar in China, was used. Five P gradients of 0, 0.01, 0.1, 0.5 and 1.0 mmol/L were set by hydroponic experiment to explore the changes of root morphology and physiological process of pitaya under different P application rates. At the same time, the content of phosphorus and other nutrient elements in the aboveground part were analyzed to clarify the mechanism of root morphological and physiological traits for efficient P use and the effect of P supply on other nutrients uptake in pitaya. The results showed that compared with no P, P fertilizer application did not affect the accumulation of aboveground biomass. P uptake and P concentration of shoot increased with the P application rates. The total root length and the number of fine roots with diameter≤0.05 mm in low P treatment (0.1 mmol/L) were significantly higher than those of other treatments. High P supply inhibited root growth, showing that the total root length was the shortest, and the number of coarse roots with diameter≥2 mm was higher than that of other treatments. Low P (0.01 mmol/L) treatment had the highest total organic acid content and higher root CEC content. Compared with no P, the organic acid secretion rate and root CEC content decreased under high P supply (1.0 mmol/L). In terms of the absorption of other nutrient elements, the absorption concentration of iron in the mother branch and the primary branch decreased gradually with the increase of P rate. The contents of nitrogen, calcium, magnesium, manganese and zinc in the second order branches decreased gradually with the increase of P rate, showing a significant negative correlation. This study showed that low P and moderate P supply (0.01 mmol/L or 0.1 mmol/L) could promote root growth, root organic acid secretion and ion absorption capacity of pitaya, while excessive P supply (1.0 mmol/L) significantly inhibited root growth and significantly reduced the absorption of trace elements accumulation in shoots. Therefore, rational application of P fertilizer is of great significance for pitaya to maximize its root biological potential and improve the P use efficiency, and also plays a key role in the balance of trace elements uptake in plants.

Pterocarpus santalinus is one of the most famous rosewood (Hongmu) species in the world. Its large-scale development is restricted due to limited seed production in China. A grafted clone seed orchard was established recently using suprior tree materials by Experiment Station of Research Institute of Tropical Forestry, Chinese Academy of Forestry in Jianfengling, Hainan Island, and most trees in the orchard have flowered and fruited. The differences in seed quality among superior trees in the introduction garden and the grafted clones need to be studied. Here the morphological traits were measured, and germination tests were conducted for the seeds of P. santalinus collected from six superior trees in the introduction garden and the grafted clones in the seed orchard at the experiment station. The coefficients of variance for the seed morphological traits were much lower than those for seedling growth traits among superior trees or the grafted clones, and the coefficients of variance was the lowest for the weight of 1000-grain seeds, indicating that the variations of seedling growth were more abundant than those of seed morphorlogy Seed length was significantly different at 0.05 level among the superior trees with No. 7 performing the best, and seed length, width and thickness differed remarkably among the grafted clones, in which No. 9^# performed the best in seed length and width, and No. 7^# did the best in seed thickness. The germination rate and potential differed significantly among superior trees (No. 3 and No. 9 performed the best, respectively) or the clones (No. 5^# did the best), and significant difference occurred in the length of epicotyl, hypocotyl, radicle and total seedling among the superior trees (No. 3 did the best), and in the length of radicle and total seedling among the grafted clones (No. 7^# did the best), demonstrating that abundant variation in seed germination and seedling growth existed among superior trees and among the grafted clones. Significance of difference between each superior tree and its clone varied with gene type, and clones performed as a whole, better than relevant superior trees in seed length and width, seed germination and seedling growth. It was indicated from relationship analysis that seed weight was significantly correlated with germination rate at 0.01 level, the germination rate of the plumper seeds was higher. In conclusion, seeds from the grafted clone seed orchard performed better in the seed morphorlogy and germination than those from the superior trees in the introduction garden, and significant difference was absent in seed weight among the superior trees or the grafted clones, and between each superior tree and its clone (P≥0.05), the seeds developed fully in the seed orchard with 1000-grain weight near 100 g, more than that for scattered individuals early grafted (92.9 g). The findings would provide scientific evidences for elite variety selection, seed orchard establishment and robust seedling cultivation.

Anthracnose is a common disease of coffee, which causes serious loss to the yield and quality of coffee fruit. The research on pathogenicity and biological characteristics of the pathogenic bacteria causing coffee anthracnose and screening of effective antagonists would provide reference for the biological control of coffee anthracnose. Four coffee anthracnose pathogens Wyq1 (Colletotrichum siamense), Yyq1 (C. fructicola), Xbd1 (C. gloeosporioides) and Hb1 (C. theobromicola) were isolated and tested for pathogenicity by spore suspension, and the most virulent strains were selected for further experiments. The biological characteristics of the pathogenic bacteria were studied by the plate culture method. Screening of antagonistic bacteria was done by the plate confrontation method. Xbd1 strain could infect healthy coffee leaves, and its virulence was the strongest among the four strains. The most suitable medium for the vegetative growth was PDA. The optimal nitrogen source was tryptone. The most suitable carbon source was glucose. The optimum temperature was 28 ℃. The optimal pH was 7. The difference of vegetative growth was not significant under different light conditions. Bacillus subtilis MC4-2, B. tequilensis D5-8, B. velezensis MC2-1 and B. flexus ZLSY3 and B. amyloliticus GJ7 showed good antagonistic effect in indoor screening. B. subtilis MC4-2 had the best antagonistic effect, with an inhibitory rate of 57.8%. The study would lay the foundation for the control of anthrax and the development of biocontrol agents.

Amomum tsao-ko (AT) is a medicinal and food homologous crop rich in polyphenols and flavonoids. The germplasm of AT is relatively mixed, and it is urgent to carry out research on AT germplasm resources and screening of high-quality AT seed sources. This study aimed to screen and evaluate the content of polyphenols and flavonoids and antioxidant activities of laxative active components of AT resources, and to explore the possible factors of component accumulation. In this study, a total of 57 samples were collected in Laos, Myanmar, Sichuan, Guangxi and Yunnan in China, and the polyphenol content and flavonoid content of AT aqueous extract were determined by forinphenol method and NaNO₂-Al (NO₃)₃-NaOH colorimetric method, and the DPPH radical scavenging ability of AT aqueous extract was detected. The correlation between polyphenol and flavonoid content, DPPH radical scavenging capacity and geographic factors was analyzed. The results showed that the content of polyphenols and flavonoids in spindle-shaped AT resources was higher than that of oval fruit and round fruit, and the content of flavonoids in AT resources abroad and Nujiang was higher than that in other regions (outside the province, western Yunnan, southwest Yunnan, Wenshan and Honghe). The content of AT polyphenols and flavonoids was significantly positively correlated with DPPH radical scavenging capacity and altitude (P<0.05), and negatively correlated with longitude (P<0.05) and latitude (P>0.05), so it was speculated that the accumulation of AT polyphenols and flavonoids may be related to temperature, light, ultraviolet rays and soil moisture. Finally, according to polyphenols, flavonoids, the classification standards were formulated, and the AT resources were divided into three grades, which would provide an analysis method for the establishment of the AT quality grade evaluation system. The excellent AT resources were screened by this method as Nujiang samples GS-3 and GS-10 and foreign samples MDL-1 and MGK-2. This study would provide a scientific basis for the investigation and collection of AT, as well as the study of origin and evolution, and also lay a solid foundation for the utilization of AT resources and the development of industry in the future.

Coconut is an important economic crop in tropics. The area of coconut palm in Hainan Island accounts for 90% of the total production area in China. Up-to-date maps of coconut palm are essential for the industrial planning of tropical agriculture. In this study, an object-oriented image analysis method was used for mapping coconut palms based on high spatial resolution imagery of Gaofen-2. Dongjiao town in Wenchang was selected as the study area. An optimal segmentation scale of Gaofen-2 imagery was obtained using the fractal evolution approach. Then, a combined layer of four original bands, five vegetation indices and 32 gray-level co-occurrence (GLCM) texture indices were used as input features. Four different sets of features (including only original bands, original bands and textures indices, original bands and vegetation indices, and all features) were applied in object-based classification. The overall accuracy (OA) and user’s accuracy (UA) of pixel-based method achieved 87.05% and 85.21%, respectively. Compared with the pixel-based method, the object-based approaches significantly increased overall accuracy (OA) between 5.51%-8.72%. The OA and user’s accuracy (UA) reached 95.77% and 97.15% respectively, which was the optimal classification result, when the combination of original bands and textural features were used in coconut palms classifying. In addition, the combination of original bands and vegetation indexes achieved a satisfactory accuracy (OA=94.88% and UA=94.42%). While the combination of original bands, vegetation indexes and textural indexes performed a lower accuracy (OA=94.67% and UA=94.17%) in comparison with that of above two combination. Generally, our researches indicate that Gaofen-2 imagery has a good potential for coconut palms classification in complex tropical regions, and the textural indexes are very useful for identifying coconut palms at object-based level. The results would provide a reference framework for tropical agriculture decision management.

The adsorption and desorption rates of nine cationic exchange resins on ergothioneine (EGT) were investigated to screen out the ion exchange resin suitable for the separation and purification of EGT from natural rubber serum (NRS) and determine the optimum process parameters. The results showed that the SA-2 cation exchange resin was the most suitable for the separation and purification of EGT from NRS, and the optimum parameters were as follows: pH of sample loading 3.0-4.0, sample loading flow rate 2 BV/h, and eluted with 0.5% ammonium hydroxide at the flow rate of 1 BV/h. Furthermore, a higher sample loading concentration was more conducive to the adsorption capacity of resin. Under the conditions, the EGT elution rate could reach 97.83%. This research indicated that the SA-2 cation exchange resin is an ideal medium for the separation and purification of EGT from NRS, which would lay a theoretical foundation for the industrial production of EGT.

Anthocyanins, also called anthocyans, are a group of plant secondary metabolites of flavonoid derivatives. Anthocyanins play an important role in mediating plant stress responses. However, whether anthocyanins are also involved in regulating phyllosphere bacterial communities remains unknown. To evaluate the differences of phyllosphere bacterial communities in plants with different anthocyanin contents, this study analyzed the phyllosphere bacterial communities of two cultivars of elephant grass with contrasting anthocyanins content, Pennisetum purpureum cv. Purple (Purple) with a high amount of anthocyanins and P. purpureum cv. Mott (Mott) with relatively low anthocyanins. The anthocyanins content determination results showed that the anthocyanins content in Purple leaves was nearly 20 times of that in Mott leaves. High throughput sequencing of 16S rRNA and analysis of the microbiome community indicated that though alpha diversity was not significantly changed, the bacterial communities of Purple was significantly different from that of Mott. In Purple, the relative abundance of endopphytic Proteobacteria and Bacteroidetes, and epiphytic Deinococus-Thermus were significantly increased, whereas epiphytic Bacteroidetes and Firmicutes were significantly decreased. The composition of microbiomes (ANCOM) at the OTU level, the relative abundance analysis at the genus level and correlation analysis between epiphytes and anthocyanins showed that the relative abundance of Methylobacterium, Unclassified Methylobacteriaceae and Deinococcus, which showed a significant positive correlation with anthocyanins content, were significantly increased in the episphere of Purple. In summary, the phyllosphere bacterial communities were significantly different between Purple and Mott. The findings from this work would provide new insights into the understanding of the superior forage value of P. purpureum cv. Purple, and lay a foundation to further investigate the mechanism of how plant secondary metabolism products regulate phylloshpere microorganisms.