Five different light filter bags including red, green, blue, white and double kraft bag were selected to study the effects of different color filter bags on the sunburn incidence and fruit quality of pomegranate. The sunburn index of pomegranate fruit decreased from 62.42% to 100%, comparing to non-bagged fruits. Principal component analysis showed that bagging mainly affected four quality indicators of pomegranate fruit, including titratable acid, soluble solids content, soluble sugar and seed hardness. The content of soluble sugar increased by 26.72% in the red bag, the seed hardness decreased by 35.58%, and the SSC and titratable acidity did not change significantly. The content of titratable acid, SSC and soluble sugar in the green bag fruit increased by 5.80%, 7.03%, 15.40% respectively, seed hardness decreased by 56.30%. The content of titratable acid, SSC and soluble sugar in the blue bag increased by 11.59%, 9.38%, 23.55%, and the seed hardness decreased by 16.26%. Titratable acid, SSC of fruits and seed hardness in the white bag decreased by 17.39%, 2.89% and 35.63%, respectively. The titratable acid and soluble solids of the fruits in the kraft bag increased by 8.70% and 11.17%, respectively, and the seed hardness decreased by 38.91%. The comprehensive analysis of the sunburn incidence and the internal and external quality of the fruit found that the red bag significantly improved the appearance quality of the fruit, reduced the fruit sunburn index by 91.80%, significantly increased the soluble sugar content, and reduced the seed hardness. Therefore, the red bag is an ideal fruit bag for Hongyushizi.

FRK1 is a marker gene downstream of the innate immunity in Arabidopsis thaliana (At), and FRKI's expression implies the initiation of the PTI pathway. This experiment screened eight FRK1-like genes from the cassava local genomic database via the Blastp method. Bioinformatics analysis reveals that all the eight FRK1-like genes encode receptor-like protein kinases with amino acid lengths between 804-921 aa and an average protein sequence length of 863 aa. The eight genes were found unevenly distributed on cassava chromosomes, mainly on chromosomes 11 and 4. The analysis of the gene structures showed that the eight genes could be classified into two groups, which in agreement with the results of the evolutionary tree analysis. Based on the location of the conserved motifs and the length of amino acid residues, it was found that MeFRK1, MeFRK4 and MeFRK5 shared three conserved motifs with AtFRK1, and the length of the conserved motifs was between 50 and 250 aa. By comparing with AtFRK1 and factoring in the results of protein motifs, chromosome positioning and evolutionary relationships, MeFRK1 was identified as a marker gene downstream of the innate immunity in the cassava genome. The experiment was conducted on cassava SC8 group-cultured seedlings, and the expression of MeFRK1 gene in leaves was measured by fluorescence quantitative PCR after treatment with the hormones SA, JA and the pathogenic bacteria Xam, respectively. The experiment unveiled that the expression of MeFRK1 gene after the treatment of hormones SA, JA and Xam all demonstrated an increasing trend followed by a decreasing one. After the treatment of the hormone SA and JA, the expression of MeFRK1 gene both peaked at 15 min, with the expression under SA treatment slightly higher than that of JA. While after the treatment of Xam, the expression peaked at 4 d at which time the expression was significantly higher than that of SA and JA treatments, 2.84 times that of the SA treatment and 3.06 times that of the JA treatment. It is evident that MeFRK1 has a positive regulatory effect in response to SA and JA signaling pathways for a short period of time, and the response is relatively rapid. Pathogenic Xam could better induce the expression of MeFRKI gene, thus improving the resistance of cassava to pathogenic bacteria Xam. The results may lay the foundation for further establishment of a molecular system for cassava disease resistance.

Cassava (Manihot esculenta Crantz) is an important food and bioenergy crop globally. One of the most significant methods for germplasm development and variety selection is hybridization. However, a series of problems including difficulty in seed germination hinder severely the development of new cultivars. Thus, in present study, seed dormancy characteristics as well as dormancy breaking methods were investigated with freshly harvested natural hybrid seeds of SC124. The cassava seeds are oval and contain a seed coat, endosperm and embryo according to the observation of anatomy and scanning electron microscopy. The outer epidermis is smooth and contains epidermal layer, spongy parenchma and densely arranged palisade parenchma from outside to the inside. The seed coat and seed caruncle slow down the water absorption of cassava seeds, while the primary reason for inducing seed dormancy is the mechanical hindrance of seed coat and the existence of the inhibitor, which could be classified as physiological dormancy. Treatments by scarified seed micropyle, removing seed coat and scarified seed micropyle + two alternating cycles of moist cold temperature (0 ℃) for 2 h followed by moist warm temperature (30 ℃) for 2 h could effectively break seed dormancy and improve seed germination percentage. Treatment by scarified seed micropyle was the most effective methods, which promoted seed germination from 2% to 88% and germination rate was also the fastest. The optimum temperature for germination of cassava seeds was 35 ℃, and the germination percentage and germination index was 88% and 36.6, respectively. The research could provide scientific basis for understanding seed structure, seed dormancy characteristics and the best broken method for cassava seeds in production practice, and also provide a theoretical reference for the expression of excellent traits of cassava hybrid offspring.

Paris polyphylla var. alba, a medicinal plant of Melanthiaceae, is classed as the national second-grade protected species of China. With the increasing demand for raw materials of Rhizoma paridis, the wild resources of P. polyphylla var. alba have been seriously damaged. In order to protect the genetic resources and clarify the systematic positon of this species, Illumina Hiseq X Ten platform was used to sequence the chloroplast (cp) genome. The structural characteristics of the complete cp genome sequence and phylogenetic relationship of P. polyphylla var. alba in Paris were analyzed. The results showed that the cp genome was 163 944 bp in length with a typical quadripartite structure with a large single-copy (LSC) region of 84 179 bp, a small single-copy (SSC) region of 12 967 bp, and a pair of 33 399 bp inverted repeats (IRs). The genome contained 134 genes, including 88 protein-coding genes (PCGs), 38 tRNA genes and 8 rRNA genes. A total of 645 long repeats and 97 simple sequence repeats (SSRs) loci were detected in the complete cp genome, in which forward and palindromic repeats were the mainly long repeat types, and most of SSRs had A/T base preference. Phylogenetic analysis based on the complete cp genomes showed that Paris formed a monophyletic group, and could be further divided into five major clades corresponding to five sections, respectively. The varieties of P. polyphylla are located in Sect. Euthyra, but are not clustered a monophyletic group, and P. polyphylla var. alba is closely related to P. mairei. This study would provide a scientific basis for studying the phylogeny, species identification and resource conservation of Paris.

A technique system for detecting the genome size of Camellia oleifera by flow cytometry was established to analyze the genome size genetic diversity between the superior lines of C. osmantha var. Yilu and C. vietnamensis var. Hongu 23, and to provide reference for selection of special germplasm and analysis of ploidy difference, based on the key links such as the type of dissociated liquid, the plant of internal reference, the tissue organ of the test material, evaluation indexes such as the nuclear dissociation, the degradation of secondary metabolites, the stability of the cell peak, the clear degree of the main peak, the separation degree of the main and miscellaneous peak, the easy degree of sampling, the difference of the genome size of the internal participating samples, the accuracy of genome size determination and the coefficient of variation. The method was used to determine the genome size of the superior lines of C. osmantha and C. vietnamensis. The disintegrating effect of WPB and mG^b was better among common dissociative fluids WPB, Tris-MgCl₂, OTTO, mG^b. Pean and corn were the favorable internal plants, and young leaf or root tip were the favorable experimental materials. The genome size of the superior lines of C. osmantha was from 5.12 to 9.31 Gb, with an average value of 7.60 Gb, the genome size distribution of the superior lines No. 1, No. 37 and No. 45 was extreme, and it was speculated that there were ploidy differences or interspecific hybridization between the parents. The genome size of superior lines of C. vietnamensis varied from 9.17 to 9.85 Gb, the mean value was 9.47 Gb. There was significant difference in genome size between the superior lines of C. osmantha and C. vietnamensis.

Pitaya has both edible and medicinal value, the major fruit in tropical and subtropical regions of China. But it is susceptible to diseases during storage. Pitaya soft rot disease is a common major disease in storage. To clarify the pathogen of pitaya soft rot, the antagonist activity and inhibition effect of antagonistic actinomycetes against pathogen, pitaya with soft rot characteristics were used to isolate pathogens by tissue separation, purification and identification. The pathogenicity of pathogen was determined by inoculated without injuries and fruit acupuncture inoculation. 26 Streptomyces spp. as the antagonist strains were tested. The inhibitory effects of cell-free filtrate on mycelial growth of the pathogen were studied by agar block method and growth rate methods. Control effect of LWL1827 cell-free filtrate spraying of different concentration and PPO, POD and PAL activity of concentration 1∶10 were carried out. ZYW18 was the pathogenic fungus according to the pathogenicity test, which was identified as Fusarium verticillioides based on morphological characteristics and molecular identification. LWL1827 could significantly inhibit the mycelia growth of ZYW18, the radius of inhibition zone was (18.32±2.13)mm, and the colony extension was inhibited significantly, the inhibitary rates of sterile fermentation filtrates with different concentrations of 1∶5、1∶10、1∶50 was 91.23%±3.11%, 87.21%±3.22%, 80.22%±2.03%, respectively. LWL1827 cell-free filtrate (1∶10) significantly improved the activity of PPO, POD and PAL, even 2-3 times higher than that of the control. Meanwhile, LWL1827 could reduce disease index and improve its control effect. Conclusively, the pathogen that causes pitaya is identified as F. verticillioides. This is the first report of pitaya caused by F. verticillioides. The Streptomyces sp. LWL1827 has significant antagonistic effect, and the antagonistic strain LWL1827 has potential value in biological control against pitaya soft sot.

In order to clearify the potential of entomopathogenic nemotodes (EPNs) on the control of Rhynchophorus ferrugineus, the pathogenucity of Heterorhabditis bacteriophora H06 against all stages of R. ferrugineus and the behavior of the invading red palm weevil larvae was studied using laboratory bioassay methods. The results showed that the mortality of eggs was the highest in all stages after R. ferrugineus was infected by EPNs, and LC₅₀ was 104.85 IJs/mL, followed by 1-2 instar larvae, 3-4 instar larvae and 5-6 instar larvae, LC₅₀ was 165.34 IJs/mL, 215.31 IJs/mL and 292.26 IJs/mL respectively; No significant differences were observed in the sensitivity between 7-10 instar larvae and pupae to EPNs. Among the effects of inoculation site on the mortality of different instar larvae, the mortality of the 3rd instar larvae was the highest when inoculated with spiracle and anus, which was 91.11% and 78.89% respectively, while the lethal rate of inoculation with mouthparts was the highest in the treatment of the 6th and 8th instar larvae. No significant difference presented in the mortality of different instar R. ferrugineus larvae when treated with vent inoculation. The R. ferrugineus body color changed to red or reddish brown, no spontaneous response when touching, and the body wall of R. ferrugineus shrinked after treated by EPNs. When the nematode approached the spiracle of R. ferrugineus larval, it stayed around the spiracle for a moment, and finally entered the insect body, and the number of EPNs successfully invaded was about 33.33%.

This study aimed to identify the pathogen which causes Areca catechu Linnaeus leaf spot and study its biological characteristics. The pathogen was isolated and purified from disease samples by the tissue isolation method, and the pathogenicity of the strain was tested. Combined with morphological characteristics and multi gene (ITS-TUB-TEF) joint analysis, a phylogenetic tree was constructed to identify the pathogen, and to study its biological characteristics under different culture conditions. Leaf spot of A. catechu was caused by Neopestalotiopsis sonneratae. The hyphal growed the fastest on CA medium and the aerial hyphal was the most developed on MEA medium. The optimum temperature for both hyphal growth and spore germination was 28 ℃. 24 h illumination was most favorable for the hyphal growth. Hyphal growed the best at pH 5, and the optimum pH for spore germination was 6. The study would provide a theoretical basis for the control of the leaf spot on A. catechu.

Cassava is an important food crop and economic crop in the world. Tetranychus urticae is one of the important alien invasive pests and one of the four major cassava pests in China. Breeding and utilization of mite resistant varieties is an important means to realize green integrated pest control. The exploitation and utilization of secondary metabolites with mite resistance function and their regulation genes can effectively breed mite resistant varieties in crops. Flavonoid play an important role in plant defense against phytophagous pests, however, there is little knowledge about the function of flavonoid pathway genes in cassava resistance to mite. Based on this, this study used mite-resistant and mite-susceptible cassava cultivars were used to analyze the flavonoid pathway genes related to plant insect resistance and to analyze the difference of gene expression after mites fed for 1 d and 4 d, respectively. The results showed that, compared with before those mites fed, the relative expression of CHS, PGT1, F3H, FLS, LAR, C3'H and CYP93B_16 genes in the cassava cultivars of BREAD, SC9 and BAR900 showed a trend of first decreasing (1 d) and then increasing (4 d) to the levels before the mites feed (0 d), while the relative expression of the above genes in the mites-resistant cassava cultivars C1115, SC9 and Myanmar showed a trend of first significantly increasing (1 d) and then decreasing (4 d). However, they were all significantly higher than those of the levels before the mites feed (0 d). Further comparison of the differences in the expression of the flavonoids synthesis pathway gene in the mites-resistant and sensitive tapioca cultivars before and after mites was infested, it was found that after the pest of the two-spotted spider mites was harmed for 1 d, the expression of CHS, PGT1, FLS and C3'H in the mites-resistant cassava cultivars was significantly higher than that in the sensitive mites cassava varieties. Correlation analysis showed that the expression of the four genes was significantly and positively correlated with cassava mite resistance. Before mites (0 d) and 4 days after mites infestation, the expression of the above genes in mites-resistant cassava varieties was generally higher than that of the tapioca cultivars. The results speculated that mite-resistant cassava cultivar could activate flavonoid pathways to defend T. urticae infestation. This study would lay a theoretical foundation for further elucidating the molecular mechanism of cassava resistance to mite, and for breeding and creating mite-resistant cassava cultivars.

Three-line matching is the main research direction of pepper breeding, identification and development of restorer gene linkage markers in pepper is a difficult problem in restorer line breeding. In this study, the F₂ segregation population was constructed by using 014A and 014C as parents, the segregation ratio of fertility and sterility was 3∶1 by χ² test, indicating that CMS fertility recovery trait of capsicum was controlled by one pair of dominant genes. Using the BSA method to construct the mixed pool of fertile and sterile DNA, the whole genome was re-sequenced and compared with the reference genome, by SNP-index Method and Fisher Test, the cytoplasmic male sterility restorer gene was mapped in the region of 1.44-8.28 Mb at the tip of the chromosome 6. The primers were designed according to the SNP/InDel difference between parents, and the polymorphic primers were screened in both parents and extreme pools, and the molecular markers PP5 and OP59 were obtained. The accuracy of the two markers was 100% in extreme population validation; The marker OP59 was a co-dominant marker, which was located at the candidate gene T459-15819 interval of 17 232 bp. The accuracy of the marker was 100% in the sterile population and 97.21% in the fertile population; PP5 was located 318 bp downstream of the candidate gene T459-15819 of the restorer gene. The accuracy of PP5 was 100% in both sterile and homozygous fertile populations. In this study, we obtained two markers closely linked with the restorer gene, which would lay the foundation for accelerating the selection of CMS restorer lines in pepper.