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.

Using the meteorological data and disaster information of 18 meteorological stations in Hainan Island in winter (from December to February of the next year) of 1971 to 2020, this paper constructed the meteorological index of chilling injury to winter vegetables with biological characteristics which not only considered the influence of overcast rain and few sunlight, but also could quantify the influence of previous cold injury processes. Combining Mann-Kendall trend test method and ArcGIS techniques, the spatiotemporal change law of chilling injury to winter vegetables in Hainan Island was obtained. The areas with high probability of chilling injury to vegetables in December, January and February and the areas with high probability of light, medium and severe chilling injury to vegetables in each month were mainly distributed in the northwest and middle of Hainan Island, while the areas with low probability were mainly distributed in the west-south-east coastal regions. The chilling injury to vegetables in each month was mainly light and moderate grade, accounting for about 88.3%. Among the three months, chilling injury to vegetables occurred most frequently in January (48.6%), and chilling injury of all grades to vegetables also occurred most frequently in January (50.2%, 43.4% and 40.2% respectively). In the recent 50 years, the annual occurrence times of cold injury to vegetables in each month of winter in Hainan Island were not significantly decreasing in most stations (83.3%, 94.4% and 72.2% respectively). Among the different grades of cold injury to vegetables in 3 months, only the annual occurrence times of severe cold injury to vegetables in February showed an increasing trend in many stations (38.9%), the annual occurrence times of other grades of cold injury were also not significantly decreasing in most stations (61.1%-88.9%). The influence scope of different grades of cold injury to vegetables in each month all decreased significantly in the order of light to severe chilling injury. Compared with each other in three months, the influence scope of cold injury to vegetables in Hainan Island were close to each other in December and February and were significantly smaller than that in January, the influence scope of light and moderate cold injury to vegetables also showed similar rules between months, while the influence scope of severe cold injury to vegetables were close to each other in December and January and were significantly larger than that in February. In the recent 50 years, the influence scope of chilling injury to vegetables in Hainan Island in December, January and February and the influence scope of different grades of chilling injury to vegetables in each month were all non-significant shrinking. In general, in the recent 50 years, the annual occurrence times of cold injury to winter vegetables was decreasing and the influence scope was shrinking, which was generally beneficial to the cultivation of winter vegetables in Hainan Island. However, in February, the annual occurrence times of severe cold injury to vegetables in eastern, central and western regions were increasing, which should be paid attention to.

In August 2022, we found Phyllanthus urinaria with yellows and witches’-broom symptoms, respectively, in areca yellows disease garden in Wenchang city, Hainan province, which were phytoplasma infection. In order to clarify the taxonomic status of the phytoplasma strain in the yellows leaves and witches’-broom of P. urinaria. In this study, we cloned the 16S rDNA gene and ribosomal protein (rp) gene, and analyzed the gene sequence consistency, phylogenetic tree and virtual RFLP. The results showed that the 16S rDNA fragment 1246 bp and rp gene 1212 bp were cloned of P. urinaria yellows phytoplasma, the 16S rDNA fragment 1827 bp and rp gene 1240 bp were cloned of P. urinaria witches’-broom phytoplasma. The gene sequence consistency showed that the 16S rDNA gene sequence of the P. urinaria yellows phytoplasma and the P. urinaria witches’-broom phytoplasma was more than 98% consistent with the phytoplasma of 16SrⅠ group, and 100% consistent with the 16S rDNA sequence of areca yellows phytoplasma Hainan strain; the consistency of them in rp gene sequences was more than 99% to those of the rpⅠ group. The phylogenetic tree analysis showed that the 16S rDNA genes of P. urinaria yellows phytoplasma and P. urinaria witches’-broom phytoplasma were clustered in a large branch with those of aster yellows phytoplasma group (16SrⅠ), and clustered in the same small branch with those of areca yellows phytoplasma of 16SrⅠ-B subgroup, with the close genetic relationship; in the phylogenetic tree of rp gene, they were clustered in a large branch with the aster yellows phytoplasma group (rp Ⅰ), and clustered in the same small branch with those of aster yellows phytoplasma of rpⅠ-B subgroup, with the close genetic relationship. The virtual RFLP analysis showed that the RFLP map obtained by the 16S rDNA gene of the P. urinaria yellows phytoplasma and P. urinaria witches’-broom phytoplasma was the same as the reference map of the onion yellows phytoplasma of 16SrⅠ-B, and the similarity coefficient was 1.00. In summary, the P. urinaria yellows phytoplasma and the P. urinaria witches’-broom phytoplasma belong to 16SrⅠ-B subgroup in classification. The results of this study could provide a theoretical basis for the prevention and control of areca palm yellow disease by eradicating its intermediate host.

Aquaporins (AQPs), assembled in tetramers at the biological membrane, constitute a class of integral membrane proteins facilitating the passive transport of water. Natural rubber, which is specifically synthesized in the laticifer located in the secondary phloem of the rubber tree (Hevea brasiliensis) trunk, is expelled out in the form of latex that represents the cytoplasmic content of laticiferous cells upon tapping. Water, accounting for approximately 70% of the latex upon each tapping, plays a crucial role in the latex production by regulating the latex viscosity and laticifer turgor. Previous studies suggested that the water balance of laticifers is governed by plasma membrane intrinsic proteins (PIPs) especially HbPIP2;3, an efficient and abundant water transporter. To uncover the regulation mechanism of HbPIP2;3 in the laticifer water balance, its 861 bp full-length coding sequence (CDS) was isolated using RT-PCR. Sequence analysis revealed that HbPIP2;3 putatively encoded 286 amino acids with the theoretical molecular weight (MW) of 30.58 kDa, the isoelectric point (pI) of 8.50, the instability index (II) of 31.68, and the grand average of hydropathicity (GRAVY) of 0.449, implying its basic, hydrophobic, and stable features. The protein was shown to contain one conserved MIP (major intrinsic protein) domain, which including six typical transmembrane helices (i.e. TM1-6) as well as two half helices (i.e. HB and HE). 3D prediction via homology modeling suggested that HbPIP2;3 could assemble in homotetramer. In accordance with the bioinformatics prediction, transient over-expression of HbPIP2;3 in Nicotiana benthamiana leaves supported the cell membrane localization, which was also confirmed by bimolecular fluorescence complementation (BiFC). Moreover, BiFC revealed that HbPIP2;3 could interact itself, which was further confirmed by yeast two-hybrid. The results showed that HbPIP2;3 may be involved in the laticifer water balance in the form of homotetramer at the plasma membrane, however, whether it could also function in hereotetramer still needs to be addressed.

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.

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.

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.

Bulbophyllum is the largest genus and the most rapidly differentiated group in the family of Orchidaceae. This paper reports 5 new recorded species of Bulbophyllum from Tibet, China. Bulbophyllum depressum King & Pantling, B. drymoglossum Maxim., B. lingii M. Z. Hang, G. S. Yang & J. M. Yin, B. menglunense Z. H. Tsi & Y. Z. Ma, B. secundum Hook. f. B. depressum is similar to B. menglunense, but the difference is that the former has very short scape and halberd-shaped lip; B. drymoglossum is a peculiar species of the genus, with small plants and no pseudobulb; B. lingii is similar to B. pentaneurum, but the difference is that the former pseudobulb is spherical and the lip is cylindrical; B. menglunense is similar to Bulbophyllum depressum, but the former has longer scape and its lip are narrowly lanceolate; the plant of B. secundum is similar to B. parviflorum, but the difference is that the middle sepal margin of the former has eyelashes, the lateral sepal margins are entire, and the lip is lanceolate. This discovery greatly enriched the background data of Orchids in Tibet, and also indicated that the investigation of orchids resources in this area was lagging behind.

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.

Screening new sugarcane varieties with high light efficiency could guarantee the high-quality development and sugar safety. Chlorophyll fluorescence parameters were measured and calculated from Lake-model for 3 commercial varieties and 10 new varieties to investigate the sugarcane photosynthetic potential under cloudy and sunny day through the mechanism model of photosynthetic electron flux (J) response to light. The results showed that light energy balanced between photosynthetic election transport and regulated energy dissipation (Φ_NPQ) under low and high light, the appearance of increased non-regulated energy dissipation (Φ_NO) under middle light resulted from the different transition mode among each sugarcane varieties according to increasing photo active radiation (PAR) other than photo-damage. Compared with in sunny day, the initial light utilization rate (α_e) of all sugarcane varieties was significantly higher in cloudy day, but J showed sharp decrease at the same PAR level. RG16117 and RG 1997 exhibited the highest photo-quantum efficiency (Φ_II) in cloudy and sunny day respectively, which showed no significantly difference between RG16239 and RG1997 under high light. Φ_II of RG16239 was lower than ROC22 and RG1997 under low and middle light with the lowest Φ_NO, but the saturate PAR and maximum J were relatively high under high light. The photosynthetic electron transport capacity index (J_PT) based on the weight ratio of cloudy and sunny days in recent 5 years exposed as RG1997 (21.93)>ROC22 (21.43)>ROC16 (20.62)>RG16239 (20.27)>GL05136 (19.43)>RG11713 (19.30)>RG1462 (19.29)>RG14291 (19.03)>RG16117 (18.94)>RG1339 (18.93)>RG1876 (18.08)>RG1 (17.41)>RG11559 (16.84), which made RG1997 and RG16239 high light efficiency varieties.