Abstract:Catalase C (CatC), as an important antioxidant enzyme, plays important roles in rice development and stress response. In order to explore the function and mechanism of CatC involved in the response to salt stress in rice, we constructed OsCatC overexpressing transgenic rice plants, and analyzed their salt tolerance and related physiology in this study. The results demonstrated that: (1) an expression vector pCUbi1390OsCatCFlag was successfully constructed, thirty independent transgenic lines (T₀) were obtained via Agrobacteriummediated callus transformation, and two OsCatC overexpressing transgenic lines (OE10, OE18) were identified by Western blot analysis of T₁ seedlings. Meanwhile, qRTPCR analysis revealed that the transcriptional levels of OsCatC in OE10 and OE18 were significantly higher than that of wildtype (WT) plants, indicating that OsCatC was successfully overexpressed and normally translated into the fusion protein CatCFlag in the transgenic lines (OE10, OE18). (2) Under normal hydroponic conditions, no significant difference was observed in the seedling growth between WT and transgenic lines OE10 and OE18, while treated with 200 mmol·L^-1 NaCl for 7 d and recovered for 10 d, the survival rates of OE10 and OE18 seedlings remained 20%-25%, whereas the majority of WT seedlings dried up and died, and the survival rate was only about 5%. (3) Compared with WT, OsCatC overexpressing seedlings (OE10, OE18) exhibited higher tolerance to salt stress with lower relative electrolyte leakage, malondialdehyde (MDA) and H₂O₂ contents, and their catalase activities were markedly increased. The growth inhibition degree of OE10 and OE18 was significantly lower than that of WT, and their seedling length was markedly higher than that of WT after treatment with 4 μmol·L^-1 methylviolet (MV) for 7 d, indicating that the transgenic lines had a stronger tolerance to oxidative stress. This study discovered that CatC reduces oxidative damage mainly by degrading the excessive accumulation of H₂O₂ under salt stress, thereby improving the salt tolerance of rice, and further verified that overexpression of OsCatC can enhance the tolerance to salt stress in rice, and that OsCatC is a promising candidate gene for the cultivation of salttolerant rice.

Abstract:In order to verify the effect of rootstock types on polyamine metabolism and floral bud dormancy of sweet cherry, this study collected the floral buds of sweet cherry variety ‘Royal Lee’ grafted in the dwarf rootstock Gisela 6 (G6) and the vigorous rootstock Mazzard as materials. Field investigations found that the dormancy process and florescence of the same sweet cherry variety grafted in dwarf and vigorous rootstocks are significantly different, and then we used the bioinformatics, gene cloning technique, realtime fluorescence quantification, subcellular localization methods to clone and do functional analysis of the key genes ［polyamine oxidase gene (PavPAOs) and arginine decarboxylase gene (PavADC)］ in the polyamine metabolism in sweet cherry floral buds. With online websites and bimolecular fluorescence complementation we predicted and verified proteins that may interact with PavADC. In addition, the content of free polyamines in floral buds was determined by high performance liquid chromatography. Results showed that: (1) the dormancy period of ‘MazzardRoyal Lee’ (75 d) is longer than that of ‘G6Royal Lee’ (69 d). And the flowering period of ‘MazzardRoyal Lee’ is later than ‘G6Royal Lee’. (2) The content of polyamines in floral bud of ‘G6Royal Lee’ is higher than that of ‘MazzardRoyal Lee’. In floral buds of ‘G6Royal Lee’, Put content was 1.2%-163.4% higher than that of ‘MazzardRoyal Lee’ and Spd content was 8.8%-261.1% higher than that of ‘MazzardRoyal Lee’. Spm was not detected in the floral buds of ‘MazzardRoyal Lee’, while was synthesized in ‘G6Royal Lee’ during January and March. (3) The key genes of sweet cherry polyamine metabolism PavPAO2, PavPAO4, PavPAO5 and PavADC were successfully cloned, and their lengths were 1 485, 1 611, 1 704, and 2 307 bp, respectively. Phylogenetic analysis showed that sweet cherry PavPAOs and PavADC are closely related to species such as Prunus persica, Prunus dulcis, and Malus domestica; subcellular localization analysis shows that PavPAO2 and PavPAO4 are located in the cell membrane, while PavPAO5 and PavADC are located in the nucleus. (4) qRTPCR analysis shows that the expression of PavPAO5 in floral buds of ‘G6Royal Lee’ is lower than that of ‘MazzardRoyal Lee’, while the expression of PavADC is higher than that in ‘MazzardRoyal Lee’ during dormancy. Throughout the dormant period, the overall expression of PavPAO2 and PavPAO4 were much lower than PavPAO5. It is speculated that PavPAO5 may be the dominant family member during the dormant period. (5) BiFC shows that PavADC could interact with PavSAMDC during the polyamine metabolism and we speculated that the two are involved in regulating the levels of polyamines in floral buds. Studies have shown that the types of sweet cherry rootstocks can affect the process of dormancy and flowering by affecting the process of polyamine metabolism. The high expression of key genes PavPAOs and PavADC can affect the level of polyamines in floral buds. PavADC can increase the content of polyamines to promote the release of dormancy and early flowering. The expression of key genes and changes in polyamine content during the process of polyamine metabolism can affect dormancy and florescence, and the increase in polyamine content can promote the release of dormancy and early flowering.

Abstract:AGO protein is the core molecule of the RNAinducible silencing complex, which plays an important role in plant growth, development and stress response. In order to explore the mechanism of AGO gene in Tibetan hulless barley resistance to barley leaf stripe, we obtained a differentially expressed gene from the transcriptional sequencing results before and after infection with barley leaf stripe in resistant Tibetan hulless barley variety ‘Kunlun14’ and the susceptible variety ‘Z1141’. The results showed that: (1) HvtAGO1 was isolated from leaves of ‘Kunlun 14’ and ‘Z1141’. We obtained a 3 675 bp sequence which contained a 3 651 bp open reading frame (ORF), encoding 1 217 amino acids in this study. Protein sequence analysis showed that HvtAGO1 was a hydrophilic unstable basic protein with highly conserved DUF1785, PAZ and PIWI domains. (2) The sequence similarity of the AOG1 protein between Tibetan hulless barely and Aegilops tauschii, Brachypodium distachyon and Triticum urartu was 96.64%, 79.34 and 80.07%, respectively, and the domain similarity of DUF1785, PAZ and PIWI was 97.57%, 98.44% and 96.02%, respectively. Phylogenetic analysis showed that the affinity of HvtAGO1 protein of Tibetan hulless barley was closest to that of A. tauschii, but far from that of Zea mays and Setaria italica. (3) The degradation sequencing proved that HvtAGO1 was the target gene of hvumiR1685p. (4) qRTPCR results showed that the expression levels of hvumiR1685p and the target gene HvtAGO1 were significantly upregulated in ‘Kunlun 14’ and ‘Z1141’ compaired with normal leaves, respectively. Meanwhile, the gene expression levels of ‘Kunlun 14’ were significantly higher than that of ‘Z1141’ under barley leaf stripe. Research speculated that hvumiR1685p and target gene HvAtGO1 play an important role in the regulation of resistance to barely leaf stripe in Tibetan hulless barley.

Abstract:In order to study the function of MAX1 in the regulation of apple branching, we cloned the MdMAX1 gene by PCR from the axillary buds of Malus domestica ‘Nagafu 2’, and carried out the bioinformatics and expression level analysis. We further analyzed the promoter activity of MdMAX1 by GUS staining. The results showed that: (1) apple MAX1 was successfully cloned and its ORF was 1 620 bp, encoding 539 amino acids. Phylogenetic analysis and motif analysis showed that MdMAX1 was similar to known A1 type MAX1. (2) qRTPCR analysis showed that MAX1 was highly expressed in the stems of ‘Changfu 2’ grafted seedlings, and also in axillary buds. RNAseq analysis showed that the expression level of MAX1 in apple axillary buds decreased significantly after treated with 6BA for 96 h. (3) The promoter sequence of ‘Changfu 2’ MdMAX1 (1 500 bp) was successfully cloned. The cis acting element prediction showed that there was a light response element in the promoter sequence of MdMAX1. GUS activity analysis showed that the activity of MAX1 promoter was weakened by light treatment. This study provides a basis for further research on the function of MAX1 involved in the synthesis of SLs in regulating apple branches in the future.

Abstract:Whirly family is a kind of plantspecific transcription factors, which play myriad roles both in the nucleus and organelles. Based on the whole genome data of Mangifera indica(mango), using bioinformatics methods to analyze the sequence of mango Whirly family genes, we studied the relative expression level of Whirly gene family by qRTPCR during the infection of Colletotrichum gloeosporioides(Cg) and Xanthomonas campestris pv. mangiferaeindicae(Xcm). The results showed that： (1) three Whirly family members, named MiWHY1, MiWHY2 and MiWHY3, were identified from the genome of mango. (2) The proteins of Whirly in mango were unstable hydrophilic basic proteins. The phylogenetic tree shows that the Whirly genes of mango are closely related to the Whirly genes of Solanum lycopersicum, Populus trichocarpa and Manihot esculenta, and there was a highly conserved sequence Motif1 in mango and Solanum lycopersicum, Populus trichocarpa and Manihot esculenta Whirly family. The Whirly family of mango contains the Whirly superfamily conservative domain, the main structural components of which are random coil and αhelix. The tetramer structure of conservative domain is similar to the tetramer structure of potato Whirly proteins. (3) qRTPCR results showed that the relative expression of mango Whirly genes were significantly upregulated during Cg infection. The relative expression levels of MiWHY1 and MiWHY3 were significantly upregulated at 12 h during Xcm infection. It was preliminarily determined that the mango Whirly gene expression responded to the infection of Cg and Xcm. In conclusion, there are three Whirly gene family members in mangosteen, and their expression level is stimulated during the infection process of pathogenic bacteria, which lays the foundation for the followup study of the functions and mechanisms of the mango Whirly gene family members.

Abstract:Rac proteins of plants belong to Rhorelated GTPase family (ROP family) and play important roles in reactive oxygen species (ROS) production, hormone signal transduction and tissue morphogenesis. Sandalwood (Santalum album Linn.) is a precious and semiparasitic plant with specialized root haustoria to absorb nutrients from other host plants. Based on the fulllength transcriptome data, a Rac protein gene was isolated from Santalum album by RTPCR and named SaRac1. The results showed that： (1) SaRac1 contains a 594 bp opening reading frame, encoding a putative hydrophilic protein of 197 amino acids with molecular weight 21.55 kD and isoelectric point 9.32. (2) Phylogenetic tree analysis showed that the amino acid sequence exhibits high similarity to AtRac1-6, AtRac9 and AtRac11 in Arabidopsis thaliana and belongs to typical Rac I proteins in plants. (3) Sequence alignment indicated the protein has conserved G domains in the Nterminal and CaaL motif in the Cterminal. (4) Subcellular localization analysis showed that SaRac1 localized in the nucleus and cytoplasm. (5) Tissuespecific expression analysis revealed that the transcript level of SaRac1 was higher in roots and haustoria than those in other issues. (6) SaRac1 was induced by 2, 6dimethoxyρbenzoquinoe (DMBQ, an important haustoriuminducing factor) and reached the highest transcript level at 4 h. These results indicate that SaRac1 might be induced by the chemical factor and involved in the development of haustorium.

Abstract:In this study, we selected the annual grapevine cv. Muscat Hamburg as the research material to explore the influence of root restriction on the growth and development of grape root system. By comparing with the traditional cultivation, we can understand the changes in grape root cell structure, IAA content and its metabolism and the expression of genes related to root growth and development after root restriction, thus explore the internal mechanism of root restriction cultivation affecting the changes of grape root system architecture. The results showed that: (1) after root restriction treatment, the architecture of grape root system changed significantly, which was mainly manifested in the appearance of a large number of clustered roots at the root tip, continuous adventitious roots, and the appearance of spiraling roots. In addition, the arrangement of root cells became looser, the root cap area of the young root tip was thicker, and the cells were larger and longer after root restriction. So, endothelial cells of the capillary roots were thickened, and the pericytes and cortical cells were larger. (2) Root restriction can significantly inhibit the content of IAA in grape roots. At 40, 100 and 205 d after planting, the changes in IAA content were consistent with the expression of key synthetic genes VvYUC6 and VvYUC8. Root restriction treatment induced the expression levels of IAA synthesisrelated genes VvTAR2, VvYUC2 and VvYUC4 to significantly upregulated during most sampling periods. At 70, 85, 130 and 205 d after planting, root restriction resulted in a significant upregulation of the expression levels of 8 genes related to IAA transport, such as VvAUX1 and VvLAX1, which coincided with the period when a high incidence of root system under root restriction. (3) Under root restriction, the expression of VvcycA1, VvcycB1, VvcycD3 and Vvcdc2 related to cell cycle regulation were upregulated from midAugust to early November. Our studies have shown that root restriction leads to changes in the configuration and cell structure of the grapevine roots, and the IAA content also changes significantly. In addition, the induction of auxin synthesis and polar transportrelated gene expression abundance changes, thereby affecting the synthesis and transport of auxin in the root system, thus adapting grapes to the root restriction cultivation environment.

Abstract:To investigate the expression and regulation mechanism of MYB in Lonicera fulvotomentosa under mineral element stress. The MYB transcription factor LfMYB of pioneer plant L. fulvotomentosa under karst landforms was isolated and identified by a combination of transcriptome sequencing and RACE cloning. Prokaryotic expression activity detection and transcription activity verification of LfMYB were carried out. The changes on the content of B element in different organs of L. fulvotomentosa were detected under different concentrations (0, 0.25, 1.0, 2.5 mg/L) of boron (B). The expression characteristics of LfMYB were analyzed by qRTPCR. The expression pattern of LfMYB was analyzed by the treatment of different concentrations (0, 0.25, 1.0 and 2.5 mg/L) of B element and qPCR analysis. The results showed: (1) LfMYB is a transcriptional activator belongs to the R2R3 MYB transcription factor family. (2) The prokaryotic expression results showed that the pCOLDLfMYB recombinant protein could be expressed after different concentrations (0.2, 0.4, 0.8 mg/L) of IPTG induction and the size of the recombinant protein is about 75 KD. The transcription experiments showed that the LfMYB protein can be transcribed and translated correctly in yeast, and LfMYB can activate transcription reporter gene. All these proved that LfMYB has selfactivating activity. (3) The results of qPCR analysis showed the expression of LfMYB in old leaves, white flowers, and yellow flowers was significantly higher than that in other parts, while the expression in young stems and young leaves was relatively low. (4) In karst soil, the B accumulated in the old leaves and stems of L. fulvotomentosa. When a certain concentration of B was applied to the karst soil, the B content in all organs of L. fulvotomentosa increased as the concentration of applied B increased, and the content of B in young stems and green buds increased most obviously, which reached a significant level (P <0.05). The expression of LfMYB increased in all organs of L. fulvotomentosa as the concentration of applied B increased. When the exogenous B concentration is 2.5 mg/L, the expression of LfMYB in all organs of L. fulvotomentosa decreased, among which the expression of LfMYB in young leaves, young stems and green buds decreased most obviously, which reached a significant level (P <0.05). This study provides an experimental basis for revealing the molecular mechanism of B tolerance in L. fulvotomentosa.

Abstract:We determined the precise sequence of peach miR167a by using miRRACE PCR reactions of the peach (Prunus persica) cultivar ‘Xiaobaifeng’, cloned three predicted target genes PpARF6, PpARF8 and PpARF6like of ppemiR167a and analyzed the phylogenetic and conserved domains of the three genes. The target genes of ppemiR167a were further identified by degradome sequencing technology, and the mode and frequency of interaction between ppemiR167a and the target genes were analyzed. The results showed: (1) the accurate sequence of ppemiR167a was different from the predicted sequence in the 1 nucleotide at the 5′ end and 3′ end. All the three target genes ARFs contained highly conserved B3 and auxin response DNA binding domains. Phylogenetic tree analysis indicated that PpARF6, PpARF8 and PpARF6like in peach were closely related to Apricot, followed by plum and sweet cherry. (2) The results of the degradome sequencing displayed that only PpARF8 could be cleavaged by ppemiR167a among the three predicted target gene and no cleavage sites were detected on PpARF6 and PpARF6like. (3) The analysis of gene expression of exogenous IAA treated peach showed that the expression of miR167a after treatment was lower than that in the CK, while the expression of its target gene PpARF8 and the 3′end cleavage production were higher than those in the CK. Taken together, these findings showed that ppemiR167a in peach fruit involved in auxin signaling pathway and participated in the regulation of fruit development by mediating the cleavage of its target gene PpARF8.

Abstract:In this study, a flavanone 3hydroxylase (F3H) gene named CmF3H was cloned from Chrysanthemum morifolium ‘14C1’. Bioinformatics analysis showed that the full length of ‘14C1’ CmF3H cDNA (GenBank: MW454869) is 1 284 bp, and the open reading frame length is 1 095 bp, encoding 364 amino acids. The theoretical molecular weight of ‘14C1’ CmF3H coding protein is 41.19 kD, theoretical pI is 5.57, the instability index is 39.51, the grand average hydropathicity is -0.465, the aliphatic index is 83.02. Amino acid alignment results indicated that ‘14C1’ CmF3H protein belongs to 2oxoglutaratedependent dioxygenase (2ODD) protein family, and has the typical characteristics of 2ODD conservative structure domain. Phylogenetic tree analysis showed that ‘14C1’ and C. morifolium ‘SU07’ were located on the same evolutionary node, which indicated that they had the closest relationship. The promoter of ‘14C1’ CmF3H was cloned by Genome Walking Method (GenBank: MW463894), its full length is 1 217 bp. The promoter sequence included light responsive element, drought and ABA responsive elements, MYB recognition and binding site as well as light responsive and organization specific expression elements. The analysis of realtime quantitative PCR indicated that CmF3H gene was expressed among different tissues of ‘14C1’ such as root, stem, leaf, bud, ligulate flower and tubular flower, the expression levels of CmF3H were the highest in tubular flower, followed by stem, leaf, bud, ligulate flower, and lowest in root. The results of this study can provide reference for the study on the biosynthesis mechanism of flavonoids in C. morifolium.

Abstract:In order to explore the molecular mechanism of the formations of Cymbidium hybrid flower color and scent, we got transcriptomic data of Cymbidium hybrid ‘Yufeng’ (K18, yellow) and ‘Fuyundanxia’ (K24, purplish red) for different flowering stages by RNASeq technique and analyzed the expression levels of genes related to flower color or scent. Present transcriptomic datas provide an important reference for the directional improvement of flower color or scent and creation of special breeding varieties. The results showed that: (1) a total of 11 914 and 6 793 differentially expressed genes (DEGs) were selected in K18 and K24, respectively; of which 58 DEGs related to flower color and scent formation base on kyoto encyclopedia of genes and genomes (KEGG) annotation. Further analysis indicated that flavonoids are the main flower pigment in K18 and K24 and expression of synthetic genes were upregulated significantly at bud stage. Among them, flavonols were generated by chalcone flavanone isomerase gene (CHI), flavonoid 3′5′hydroxylase gene (F3′5′H) and flavonol synthase gene (FLS) in K18; Anthocyanins were got by anthocyanidin synthase gene (ANS) in K24. (2) qRTPCR analysis showed that the expression levels of hydroxymethylglutarylCoA synthase gene (HMGS), hydroxy3methylglutaryl coenzyme A reductase gene (HMGR2), mevalonate5diphosphatase gene (MVD) and so on in terpenoid skeleton biosynthesis all are the highest at the flowering period in K18. Moreover, the expression levels of six TPSs in K18 were more than 100 times than that in K24. (3) Quantitative analysis showed anthocyanin content in K18 (122.28 μg·g^-1) was about 20% of that in K24 (608.74 μg·g^-1). The main pigment component in K24 was cyanidin, which made the flower color red, while the delphinin level in K18 was relatively high (the yellow flower). Study speculated that the overexpression of ANS may be one of the reasons for higher anthocyanin content in K24 petals than that in K18. Flavonol rather than anthocyanin was accumulated in K18 through CHI, F3′5′H and FLS pathway, which affects the determination of flower color.

Abstract:We studied the genetic diversity and genetic relationship of 28 melon parent materials using 2bRAD genotyping by sequencing, to provide a scientific basis for molecular marker assisted breeding of melon. The results showed that: (1) there were 10 318 SNPs in 28 melon germplasms, the ratio of transitions to transversions in SNPs was 2.15, and the mean value of the genetic variation and genetic distance between different germplasms were 0.88 and 2.22, respectively, implying the high degree of genetic differentiation among these germplasms. (2) According to the characters of skin color, fruit reticulation and flesh color, the 28 melon germplasms were separately divided into 4 populations (containing white skin population, yellow skin population, cyan skin population, and green skin population), 3 populations (containing smooth skin population, thin reticulation population, and dense reticulation population) and 3 populations (containing white flesh population, orange flesh population, and green flesh population). (3) The phenotypic analysis result showed that the degree of genetic differentiation among the populations classified by the skin color was the highest, and the value of the genetic variation was between 0.05 and 0.19, indicating a moderate or above level of genetic differentiation among the four populations; a moderate level of genetic differentiation was observed between smooth skin population and dense reticulation population, while there was no significant genetic differentiation between smooth skin population and thin reticulation population or between thin reticulation population and dense reticulation population; a moderate level of genetic differentiation was observed between white flesh population and orange flesh population, while there was no significant genetic differentiation between white flesh population and green flesh population or between orange flesh population and green flesh population. (4) These melon germplasms were divided into three subgroups by analysis of the phylogenetic tree. Specifically, the first subgroup had 11 germplasms (the parental germplasms were mainly selfselected melon varieties), the second subgroup had 9 germplasms (most of the parental germplasms were introduced from Xinjiang or selected from Xinjiang melon varieties), and the third subgroup had 8 germplasms (most of the parental germplasms were introduced from Japan or selected from Japanese melon varieties). The results of this study indicated that the clustering result of melon based on the molecular level exhibited a certain relationship with that of geographical origin, but it was not completely consistent with the result of the breeders classification about the breeding materials basing on skin color, fruit reticulation and flesh color.

Abstract:Chloroplast DNA fragments (rbcL, trnSG) and nuclear ribosomal DNA internal transcribed spacer (ITS) were employed for studing population genetic diversity of Saxifraga atrata, which has a narrow distribution range endemic to the Qilian Mountains. The aim was to reveal genetic structure and population historical evolution of S. atrata. The results showed that: (1) four cpDNA and nine ITS haplotypes were isolated among the 115 individuals. Populations from the southeast edge of the Qilian Mountains showed high haplotype richness and uniqueness, whereas northwest populations only harbored a few widespread haplotypes and usually showed low levels of genetic diversity. (2) Analysis of molecular variance (AMOVA) based on both cpDNA and ITS datasets showed that most variations were from withinpopulations. (3) Neutrality tests based on cpDNA dataset exhibited negative values, but not significant. However, mismatch distribution analysis strongly supported a recent expansion of S. atrata. According to extant genetic structure, we speculated that S. atrata retreated to the southeastern refugia of the Qilian Mountains during the Quaternary. The northwest populations were the result of recolonization during interglacial or postglacial periods. Founder effect associated with recolonization should be responsible for haplotype impoverishment and low levels of genetic diversity of northwest populations. Bottleneck effect and genetic drift might be much severe in this narrow endemic species due to small population size and fragmentation, resulting in extremely low levels of total genetic diversity and average withinpopulation diversity compared with other Saxifraga species widespread in the QinghaiTibet Plateau and Himalayas.

Abstract:After the conversion from farmland to forest of northern Shaanxi Province in Loess Plateau, biocrust has become a typical surface cover type, which is rich in soil algae and plays an extremely important role in fixing soil and promoting nutrient cycling. In this study, soil algae of northern Shaanxi in Loess Plateau were isolated and cultivated by coating plate method and water droplet dilution method. Morphological characteristics of microalgae were observed by optical microscope, and molecular identification of single algae was carried out, which laid a foundation for the study of biocrusted algae of northern Shaanxi in Loess Plateau. The results showed that: (1) a total of 7 species of crusted algae were purified and identified by optical microscopy, among which 5 were green algae and 2 were cyanobacteria. (2) The sequence lengths of five green alage strains of SM21, DB21, DB22, SD1 and SD2 were 664 bp, 663 bp, 662 bp, 589 bp and 688 bp, and GC contents were 33.43%, 49.47%, 50.15%, 50.76%, 51.01%, respectively; The sequence lengths of YJ3 and YJ2 strains of cyanobacteria were 570 bp and 465 bp, and GC content was 46.31% and 49.03%, respectively. (3) Sequence alignment and phylogenetic tree analysis showed that the 5 green algae could be divided into four clades: Scenedesmaceae (2 strains: DB21 and SM21), Chlamydomonadales, Shaeropleaceae and Eustigmataceae, respectively. And the 5.8S+ITS2 sequences of the 5 green algae showed little difference within the genus and were very conservative, which made it easy to identify the genus. 2 strains of cyanobacteria, YJ3 and YJ2, were clustered in the same big branch of Pseudanabaenaceae, but they belonged to different genus. The research suggests that DB21 was a species of Scotiellopsis, SM21 belonged to Acutodesmus, DB22 belonged to Haematococcus, SD1 was a species of Ancyra, and SD2 belonged to Eustigmatos.YJ3 may be a new species of Pseudanabaenaceae, and YJ2 may be a new species of Leptolyngbya.

Abstract:To explore the mechanism of pigment content and cell structure on the flower color formation of Michelia crassipes, we determined the content of pigment and cell ultrastructural in its perianth during 2 different colors. The relationship between pigment content and color formation of perianth was analyzed by stepwise regression equation, and the ultrastructural changes of tepals were observed by paraffin section and ultrathin section technology. The results showed that: (1) the L^* values of purple perianth surface were decreased, as did the b^* values, but the a^* values were enhanced. The accumulation of anthocyanins and the increase of carotenoids and flavonoids in perianth were accompanied by the degradation and decrease of chlorophyll content. (2) a^* was positively correlated with the content of anthocyanins, flavonoids, carotenoids and anthocyanins/flavonoids, anthocyanins/chlorophyll, while b^* was positively correlated with chlorophyll content and anthocyanins/carotenoids; (3) in cellular structure, as the perianth turns from green to purple, upper epidermal cells change from flat to conical protrusions, lengthwidth ratio increases and anticlinal walls folds. The epidermal structure of purple perianth absorbed more incident light and the increase of vacuole area and the transformation of chloroplasts into chromoplasts were the main organelle changes. It was found that the coloration of perianth was the result of many factors. The generation and accumulation of anthocyanin content and the increase of carotenoid and flavonoid content may be the main reasons for the purple color of M. crassipes, with the ultrastructure shows that the vacuole area increased and chloroplast transformed into plasmid.

Abstract:In this study, the fresh flower apparatus, new branches, leaves and fruits of healthy ‘Kuerlexiangli’ pear trees were used as experimental materials, we obtained endophytic bacteria strains and culture colonies with the method of endophytic bacteria isolation in plant tissues. The bacteria with bacteriostatic effect on Erwinia amylovora, Pseudomonas syringae pv. syringae and Valsa mali var. pyri were screened by plate confrontation culture and rescreening of fermentation broth. We tested the control effect of antagonistic strains against pear fire blight by spraying ‘Kuerlexiangli’ pear inflorescences in vitro and potted birch pear seedlings, in order to explore the biocontrol resources of endophytic bacteria and lay a foundation for exploring the biological control ways of pear diseases. The results showed the following: (1) a total of 337 endophytic bacterial strains were isolated from branches, leaves, flowers and fruit tissues of ‘Kuerlexiangli’ pear, of which 14 strains had obvious bacteriostatic activity. 8, 9 and 4 strains of bacteria with bacteriostatic effect on E. amylovora, P. syringae pv. syringae and V. mali var. pyri were further screened. Among them, ZN5, SN19 and HN9 strains had antagonistic effect on P. syringae pv. syringae and V. mali var. pyri pathogen, while HN89 strain showed potent bacteriostatic effect on three kinds of pathogens. A total of 7 strains (SN37, HN89, HN98, HN143, HN126, TN68 and TN16) with bacteriostatic effect against E. amylovora and competitive strains TN50 were screened. (2) The pretreatment (spraying) of endophytic strain TN50 had a significant effect on preventing flower rot of ‘Kuerlexiangli’ pear, and its control effect (52.36%) was similar in agricultural streptomycin (60.67%); followed by HN89(39.66%). The pretreatment (spraying) of endophytic strains TN50, HN89 and SN37 could significantly reduce the branch withering rate and disease index of potted birch pear seedlings (P < 0.05). The average protective control effect of 7~15 d was 67.20%, 54.32% and 45.91%, respectively, and the therapeutic control effect was 63.88%, 52.10% and 36.17%, respectively. (3) Based on the morphological characteristics and 16S DNA sequence, TN50, HN89 and SN37 were identified as Klebsiella sp., Paenibacillus sp. and Pseudomonas sp., respectively.

Abstract:Using the flower buds of Huizao and Junzao as materials, we determined the changes of soluble sugar, reducing sugar, starch, soluble protein contents, SOD, POD, PPO, CAT activities and endogenous GA₃, IAA, ABA, ZT contents in flower buds at different differentiation stages, and discussed their relations with flower bud differentiation, so as to provide theoretical reference for the regulation of flower bud differentiation of Zizyphus jujuba. The results showed that: (1) the changes of soluble sugar, reducing sugar and starch contents of Huizao and Junzao during flower bud differentiation were basically similar. The contents of soluble sugar, reducing sugar and starch first decreased and then increased from flower primordium differentiation stage to pistil differentiation stage, and reached the peak at pistil differentiation stage; On the contrary, the contents of protein and carbohydrate first increased and then decreased from flower primordium differentiation stage to pistil differentiation stage. (2) With the beginning of flower bud differentiation, the activities of POD, PPO and CAT decreased gradually, and the lowest point appeared in pistil differentiation stage; the activity of SOD increased significantly from primordium differentiation stage to early differentiation stage, and then the activity of SOD decreased in Huizao, while increased in Junzao significantly. (3) The changes of IAA, GA₃, and ZT contents during flower bud differentiation are basically similar. IAA, GA₃, and ZT show a downward trend before the sepal differentiation stage, and then the contents of GA₃, ZT and content of IAA in Huizao increased gradually, while the content of IAA in Junzao first increased significantly, then decreased and then increased from sepal differentiation stage to petals differentiation stage; the content of ABA increased significantly from primordium differentiation to sepal differentiation, but decreased significantly in Junzao. With the advance of differentiation, ABA content of Huizao decreased gradually after sepal differentiation, while increased gradually in Junzao and reached the peak at pistil differentiation. (4) With the beginning of flower bud differentiation, the ratios of ABA/IAA, ZT/IAA and GA₃/IAA increased rapidly, but the ratios of GA₃/ABA and ZT/ABA decreased; The ratios of ZT/IAA and GA₃/IAA were significantly increased and then decreased from primordial differentiation stage to sepal differentiation stage. After differentiation, the ratios of ZT/IAA and GA₃/IAA were lower than those at primordial differentiation stage. The results suggested that after the flower buds of jujube start to differentiate, they consume a lot of nutrients, the soluble sugar, starch and reducing sugar contents of the flower buds are reduced, and the starch content is always higher than the soluble sugar and reducing sugar during the whole differentiation process. The decrease of POD, CAT, PPO activities during the flower bud differentiation process of the two varieties, and the increase of SOD activity during the flower bud differentiation process of Junzao, are conducive to the transition from vegetative growth to reproductive growth; In the process of jujube flower bud differentiation, low levels of GA₃ and IAA, medium level of ABA, higher level of ZT and high ratios of ZT/IAA, ABA/IAA and GA₃/IAA are beneficial to the differentiation and formation of jujube flower buds.

Abstract:Ephemeral plants are an important part of the desert system in China, and slope direction is one of the most important topographic factors in Junggar Desert, which may affect the biomass and stoichiometric characteristics of ephemeral plants in this area. In this study, we detected the biomass allocation and stoichiometric characteristics of different organs (roots, stems, leaves and reproductive organs) of Malcolmia africana and _{Alyssum linifolium}, two ephemeral plants of the Brassicaceae family, in different slope directions (east slope, west slope and north slope) to explore the adaptation strategies of ephemeral plants. The results showed that: (1) the plant biomass of two ephemeral plants was significantly different on different slopes, but the plant biomass of M. africana was the largest on the west slope (1.1±0.0134 g). The plant biomass of A. linifolium was the largest on the north slope (1.45±0.0113 g) and the smallest on the east slope (0.5±0.0084 g). (2) The biomass distribution of M. africana organs was expressed as the leaves > stems > propagating organs > roots, and the proportion of the organs was similar on different slopes. Biomass distribution of organs of A. linifolium was significantly different in different slope directions, and the biomass of roots was significantly lower than that of other organs (P<0.05), among which the northern slope had the largest proportion of reproductive organs, the eastern slope had a large proportion of leaves, while the western slope had little difference in the proportion of root, stem and leaf biomass. (3) Biomass of two ephemeral plants in different slope directions was significantly positively correlated with C, N and P stoichiometry. (4) The N/P values of the two ephemeral plants in different slope directions were all less than 14, indicating that the growth of plants was limited by N. M. africana adjusts its size to suit different environments, while A. linifolium adjusts the proportion of its organs to suit the changing environment. It suggested that ephemeral plants have a strategy to adapt to desert environment by adjusting nutrient and biomass allocation. In the low mountain and hilly areas of Junggar desert, slope orientation is the main environmental factor affecting biomass allocation and stoichiometric characteristics.

Abstract:To evaluate the potential distribution of Rosa roxburghii in China under the background of climate change, we simulated the potential geographical distribution of R. roxburghii under current and future climate scenarios based on natural distribution data of R. roxburghii, and the current (1960-1990) and future (2050s and 2070s) climate factor data using MaxEnt software, and to identify the main climatic factors affecting its geographical distribution. The results showed that: (1) temperature factor is a key climate factor affecting R. roxburghii distribution, especially the percent contribution and permutation importance of the min temperature of coldest (BIO06) to the model were 66.7% and 53.4%, respectively. (2) Under the present climate conditions, the total suitable area of R. roxburghii is 3.50×10⁶km², accounting for 36.44% of Chinas land area. Among them, the highly suitable area is 2.05×10⁵km², accounting for 5.87% of the total suitable area, and it is mainly distributed in western Guizhou, central Sichuan, and SichuanChongqingShaanxi border. (3) Under the future climate change scenario, the total and lowly suitable regions of R. roxburghii will increase, while the moderate and high suitable regions will decrease. Under the condition of RCP4.5 in 2070s, the moderately and highly suitable regions will be the minimum, which are 7.08 × 10⁵ km² and 2.80 × 10⁴ km², respectively, accounting for only 53.30% and 13.65% of the moderately and highly suitable regions in current region. It indicated that the suitable region of R. roxburghii increased slightly with the climate change and tended to move to high latitude area. The highly suitable area of central Sichuan, and SichuanChongqingShaanxi border are significantly reduced, and will be mainly distributed in Guizhou Province in the future.

Abstract:The research of plant signal peptides mainly focuses on small molecular peptides. As a key component of intercellular communication, small molecular peptides are mainly involved in signal interference, response pathways, display antimicrobial activity, and interaction with receptor kinases on the surface of cell membranes in the form of ligands, which are enable signal communication between cells. Small peptide molecules are important intercellular signal sensing molecules that are critically involved in regulating growth and development processes and stress responses in response to biotic and abiotic stresses in different organ tissues and developmental stages of plants to coordinate and integrate cellular functions. This review indicates a comprehensive overview of the discovery, structural features, classification system, and functional progress of plant small molecule peptides, and focuses on recent years at home and abroad on the CLE (clavata3/ESR) family of posttranslational small peptides and Ralf (rapid alkalinization factor) family of cysteine rich peptides, provides basic information for indepth studies of plant small molecule peptides and reference for future research directions.