Genome-wide analysis of R2R3-MYB transcription factors in poplar and functional validation of PagMYB147 in defense against Melampsora magnusiana.

MAIN CONCLUSION: Transcription of PagMYB147 was induced in poplar infected by Melampsora magnusiana, and a decline in its expression levels increases the host's susceptibility, whereas its overexpression promotes resistance to rust disease. Poplars are valuable tree species with diverse industrial and silvicultural applications. The R2R3-MYB subfamily of transcription factors plays a crucial role in response to biotic stresses. However, the functional studies on poplar R2R3-MYB genes in resistance to leaf rust disease are still insufficient. We identified 191 putative R2R3-MYB genes in the Populus trichocarpa genome. A phylogenetic analysis grouped poplar R2R3-MYBs and Arabidopsis R2R3-MYBs into 33 subgroups. We detected 12 tandem duplication events and 148 segmental duplication events, with the latter likely being the main contributor to the expansion of poplar R2R3-MYB genes. The promoter regions of these genes contained numerous cis-acting regulatory elements associated with response to stress and phytohormones. Analyses of RNA-Seq data identified a multiple R2R3-MYB genes response to Melampsora magnusiana (Mmag). Among them, PagMYB147 was significantly up-regulated under Mmag inoculation, salicylic acid (SA) and methyl jasmonate (MeJA) treatment, and its encoded product was primarily localized to the cell nucleus. Silencing of PagMYB147 exacerbated the severity of Mmag infection, likely because of decreased reactive oxygen species (ROS) production and phenylalanine ammonia-lyase (PAL) enzyme activity, and up-regulation of genes related to ROS scavenging and down-regulation of genes related to PAL, SA and JA signaling pathway. In contrast, plants overexpressing PagMYB147 showed the opposite ROS accumulation, PAL enzyme activity, SA and JA-related gene expressions, and improved Mmag resistance. Our findings suggest that PagMYB147 acts as a positive regulatory factor, affecting resistance in poplar to Mmag by its involvement in the regulation of ROS homeostasis, SA and JA signaling pathway.

Protocatechuic acid, ferulic acid and relevant defense enzymes correlate closely with walnut resistance to Xanthomonas arboricola pv. juglandis.

BACKGROUND: Juglans regia L. is an important nut tree that has a wide range of distribution in temperate regions of the world. In some walnut orchards, walnut blight can become a problematic disease that affects the growth of walnut trees. To explore the correlation between biochemical response and walnut resistance, we inoculated four walnut cultivars with Xanthomonas arboricola pv. juglandis (Xaj). The walnut cultivars were, namely, 'Xiangling', 'Xiluo 2', 'Yuanfeng' and 'Xifu 2'. Total phenol content (TPC) and total flavonoid content (TFC) were measured, whereby nine major phenolic compounds and several relevant enzymes were identified. RESULTS: The results showed that the most resistant and susceptible walnut varieties were 'Xiluo 2' and 'Xifu 2' respectively. The reaction of walnut to Xaj was characterized by the early accumulation of phenolic compounds in the infected site. After inoculation with Xaj, we found that the resistant variety 'Xiluo 2' show the significant differences with other varieties at different time points through the determination of related antioxidant enzymes such as catalase (CAT) and peroxidase (POD). Meanwhile, the phenylalanine ammonia lyase (PAL) of 'Xiluo 2' increased significantly at 8 day post infection (dpi) and made differences from the control samples, while other varieties changed little. And the polyphenol oxidase (PPO) was significantly higher than in the control at 16 dpi, maintaining the highest and the lowest activity in 'Xiluo 2' and 'Xifu 2' respectively. It was also found that the content of protocatechuic acid in all cultivars increased significantly at 4 dpi, and 'Xiluo 2' was significantly higher than that of the control. In the early stage of the disease, ferulic acid content increased significantly in 'Xiluo 2'. CONCLUSION: Our findings confirmed that the metabolism of phenolic compounds and related defense enzymes are of great significance in the response of walnut to Xaj.

Ontogenetic Variation in Macrocyclic and Hemicyclic Poplar Rust Fungi.

Melampsora larici-populina (Mlp), M. medusae (Mmed), M. magnusiana (Mmag), and M. pruinosae (Mpr) are epidemic rust fungi in China. The first two are macrocyclic rust fungi distributed in temperate humid environments. The latter two are hemicyclic rusts, mainly distributed in arid and semi-arid areas. Ontogenetic variation that comes with this arid-resistance is of great interest-and may help us predict the influence of a warmer, drier, climate on fungal phylogeny. To compare the differences in the life history and ontogeny between the two types of rust, we cloned mating type genes, STE3.4 and STE3.3 using RACE-smart technology. Protein structures, functions, and mutant loci were compared across each species. We also used microscopy to compare visible cytological differences at each life stage for the fungal species, looking for variation in structure and developmental timing. Quantitative PCR technology was used to check the expression of nuclear fusion and division genes downstream of STE3.3 and STE3.4. Encoding amino acids of STE3.3 and STE3.4 in hemicyclic rusts are shorter than these in the macrocyclic rusts. Both STE3.3 and STE3.4 interact with a protein kinase superfamily member EGG12818 and an E3 ubiquitin protein ligase EGG09709 directly, and activating G-beta conformational changes. The mutation at site 74th amino acid in the conserved transmembrane domain of STE3.3 ascribes to a positive selection, in which alanine (Ala) is changed to phenylalanine (Phe) in hemicyclic rusts, and a mutation with Tyr lost at site 387th in STE3.4, where it is the binding site for ß-D-Glucan. These mutants are speculated corresponding to the insensitivity of hemicyclic rust pheromone receptors to interact with MFa pheromones, and lead to Mnd1 unexpressed in teliospora, and they result in the diploid nuclei division failure and the sexual stage missing in the life cycle. A Phylogenic tree based on STE3.4 gene suggests these two rust types diverged about 14.36 million years ago. Although these rusts share a similar uredia and telia stage, they show markedly different wintering strategies. Hemicyclic rusts overwinter in the poplar buds endophytically, their urediniospores developing thicker cell walls. They form haustoria with a collar-like extrahaustorial membrane neck and induce host thickened callose cell walls, all ontogenetic adaptations to arid environments.

Pestalotiopsis trachicarpicola, a novel pathogen causes twig blight of Pinus bungeana (Pinaceae: Pinoideae) in China.

Pinus bungeana is one of indigenous trees in China and widely distributed in poor and arid regions for vegetation and industrial woody use. However, since a high-incidence disease threatens the growth of mature P. bungeana tree in the garden and in the plantation every year, the overwintering shoots were infected and died in the next spring with a ratio over 70%, but the cause was beyond understood. A total of 120 fungal isolates were separated from symptomatic twigs by histological isolation methods, including Pestalotiopsis spp., Fusarium spp., Trichothecium spp., Penicillium and some unknown fungal species. Pestalotiopsis spp. was dominant, accounting for 85%. Morphological observation under microcopy showed all Pestalotiopsis species are identical, and six isolations among them were randomly selected for pathogenicity tests. Fulfilling Koch's postulates showed that all six isolates of Pestalotiopsis spp. were pathogens of twig blight, causing the same symptoms as observed in the field, while other non-Pestalotiopsis isolates were avirulent to P. bungeana twigs. Multi-gene (ITS, tub2 and TEF1) analysis and morphological observation revealed that all the six Pestalotiopsis isolates belonged to P. trachicarpicola. To our knowledge, this is the first study reporting P. trachicarpicola as the pathogens responsible for P. bungeana twig blight in China.

First Report of Leaf Rust of Acer mono Caused by Pucciniastrum hikosanense in China.

Acer mono Maxim, mainly distributed in China, Japan, Korea and eastern Russia (Shang et al. 2012), is a widely planted ornamental and pharmaceutical tree (Zhang et al. 2015). In September 2020, leaf samples of A. mono infected by uredinia were collected in Shaanxi Province (34°15'40.06'' N, 108°3'54.54'' E, alt. 432.35m), China. Telia development was observed in late autumn. Voucher specimens were deposited in the Herbarium Mycologicum Academiae Sinicae (no. HMAS249354), China. This led to premature defoliation and in the 90% planting wide incidence. Geospatial investigations revealed that this rust was widely distributed in local urban parks, but was nonpathogenic to A. buergerianum, A. negundo, A. oblongum, A. palmatum and A. rubrum. This fungus was morphologically characterized and most closely matched descriptions of Pucciniastrum. Uredinia were hypophyllous, subepidermal, scattered to gregarious, oval or round, 0.10-0.30 × 0.08-0.15 mm, golden yellow to orange, somewhat pulverulent. Peridia were hemispherical, erumpent with apical pores; peridial cells minute, irregularly polygonal, hyaline to pale yellow; ostiolar cells ellipsoid or roundish. Urediniospores were subglobose, ovate or ellipsoid, 20-33 × 15-21 µm, yellow to pale orange; wall 1-2 µm thick, hyaline to pale yellow, echinulate, somewhere smooth. Pedicels were deciduous, hyaline, minute, fragile. Telia were hypophyllous, subepidermal, intermixed with uredinia, irregularly polygonal, restricted by veins, 0.34-0.91 × 0.21-0.54 mm, and orange to amber brown. Teliospores were produced parallelly single-layered, and were subglobose, oblong, sometimes angular, 23-47 × 16-34 µm, colorless to pale yellow, 1-5 mediastinal, 2-6-celled; lateral wall 1-1.6 µm thick, apical wall 1-3 µm thick, smooth, hyaline. The internal transcribed spacer (ITS) and rDNA-28S regions were amplified using ITS1F/ITS4 and NL1/NL4 (Ji et al. 2019) to confirm the identification. The aligned sequences were deposited in GenBank (accession no. MW391829, MW543709, MW541916, MW541917). Phylogenetic trees were constructed based on neighbor-joining (NJ), maximum-likelihood (ML) and Bayesian methods. ML and NJ bootstrap values were calculated by bootstrap analyses of 1,000 replicates with GTR+G+I model using MEGA-X (Kumar et al. 2018), while Bayesian Markov chain Monte Carlo analyses were performed using MrBayes ver. 3.1.2 (Huelsenbeck & Ronquist 2001; Ji et al. 2019). Phylogenetic analysis revealed that HMAS249354 and Pucciniastrum hikosanense were grouped into one clade highly supported by bootstrap values of NJ, ML, and Bayesian posterior probability (Bpp) of 97%/93%/1, respectively. Koch's postulates were fulfilled with 1-year-old healthy plants of A. mono. Fresh urediniospores were collected and suspended in a 0.05% water solution of Tween 20, and 100 µl of urediniospores suspension (106 urediniospores/ml) per leaf (n=10) were sprayed, with another ten healthy leaves sprayed with sterile water as the control. The plants were placed in dark for 48 h and then moved into greenhouse at 22°C with 12 h light per day. Disease symptoms after 10-12 days' inoculation on the inoculated leaves which were identical to the original observations, while the control leaves remained healthy. Previously, P. hikosanense was reported to infect Acer rufinerve Sieb. et Zucc. in Japan (Hiratsuka 1940) and A. rubescens Hayata in Taiwan, China (Dai 1979). This is the first report of leaf rust of Acer mono caused by Pucciniastrum hikosanense Hirats. f. in China.

First report of alternate hosts of willow rust disease caused by Melampsora ferrinii in China.

Corydalis acuminata Franch., C. edulis Maxim. and C. racemosa (Thunb.) Pers. of family Papaveraceae are rich in multiple alkaloids and widely used as Chinese medicinal herbs, for treating cough, pruritus, sores tinea and snake venom (Zhang et al. 2008, Iranshahy et al. 2014). In April 2021, orange rust pustules were observed on C. acuminata, C. edulis and C. racemosa in Shaanxi Province (34°4'56'' N, 108°2'9'' E, alt. 770 m), China. Samples were collected and voucher specimens were preserved in the Herbarium Mycologicum Academiae Sinicae (nos. HMAS249947-HMAS249949), China. Consequent geospatial investigations revealed that diseased plants can be observed at an altitude of 400-1000 m, and show an incidence from 40% to 80% varied by altitude. Spermogonia epiphyllous, subcuticular, densely grouped, oval or round, 0.14-0.36 × 0.09-0.30 mm, pale orange-yellow, and type 3 of Cummins and Hiratsuka (1963). Aecia mostly hypophyllous, subepidermal without peridia, Caeoma-type, erumpent, densely grouped, oval or round, 0.27-0.85 × 0.15-0.43 mm, and orange-yellow; hyaline peridial cells produced in a periphery of the sorus under the ruptured epidermis of host plants. Aeciospores globoid or broadly ellipsoid, catenulate with intercalary cells, 15.7-20.1 × 10.8-15.7 µm, yellow to pale orange; walls hyaline, verrucose, 1.7-3.1 µm thick. This fungus was morphologically identified as Melampsora (Melampsoraceae). The rDNA-28S and the internal transcribed spacer (ITS) regions were amplified using primers NL1/NL4 and ITS1/ITS4 (Ji et al. 2020; Wang et al. 2020). Bi-directional sequences were assembled and deposited in GenBank (accession nos. MW990091-MW990093 and MW996576-MW996578). Phylogenetic trees were constructed with the ITS+rDNA-28S dataset based on maximum-likelihood (ML), maximum-parsimony (MP) and Bayesian Inference (BI). ML and MP bootstrap values were calculated by bootstrap analyses of 1,000 replicates using MEGA-X (Kumar et al. 2018), while BI posterior probabilities (Bpps) were calculated using MrBayes ver. 3.1.2 (Ji et al. 2020; Wang et al. 2020). Phylogenetic analyses grouped our specimens and Melampsora ferrinii Toome & Aime into one clade, highly supported by bootstrap values of ML, MP, and Bpps of 100%/100%/1. Inoculations were conducted with 1-year-old plants of original host, Salix babylonica L. (Toome & Aime 2015). Aeciospores suspension with a concentration of 106 spores/ml were sprayed on 20 healthy leaves, with another 20 healthy leaves sprayed with sterile water as the control. The inoculated plants were kept in darkness at 20-25 °C for 2 days and then transferred into greenhouse at 23°C with 16 h light per day. After 8-10 days of inoculation, yellow pustules of uredinia appeared on abaxial surfaces of the inoculated leaves, which were identical to Toome & Aime (2015) reported, while the control leaves remained healthy. Inoculations with the same method were conducted by spraying urediniospores, and the same rust symptoms developed after 8 days. Genus Corydalis was verified as the alternate host of M. chelidonii-pierotii Tak. Matsumoto, M. coleosporioides Dietel, M. idesiae Miyabe and M. yezoensis Miyabe & T. Matsumoto (Shinyama & Yamaoka 2012; Okane et al. 2014; Yamaoka & Okane 2019), and C. incisa (Thunb.) Pers. was speculated as the potential alternate host of M. ferrinii (Toome & Aime 2015). Based on morphology, phylogeny and pathogenicity, we firstly report M. ferrinii in mainland China and verify C. acuminata, C. edulis and C. racemosa instead of C. incisa as its alternate hosts.

Integrated Analysis of Seed microRNA and mRNA Transcriptome Reveals Important Functional Genes and microRNA-Targets in the Process of Walnut (Juglans regia) Seed Oil Accumulation.

Walnut (Juglans regia) is known as a promising woody oil crop with abundant polyunsaturated fatty acids in its kernel. However, the regulation mechanism of walnut oil accumulation and fatty acid metabolism is still poorly understood, which restricted the breeding and genetic improvement of high-quality oil-bearing walnuts. To reveal the molecular mechanism of walnut oil accumulation, considering the potential regulation of microRNA (miRNA) in seed development, in this study, the oil content of walnut kernel on the 80th, 100th and 120th day after flowering (DAF) was tested and the corresponding proportions are 11.51%, 40.40% and 53.20%. Between DAF of 80th~120th, the content of stearic acid and oleic acid tended to increase, but the proportion of other fatty acids tended to decrease. Meanwhile, comparative transcriptome and sRNA-seq analysis on three stages (80th, 100th and 120th DAF), found 204 conserved miRNAs and 554 novel miRNAs in walnut kernels, among which 104 key genes related to walnut oil accumulation were screened. The phospholipid:diacylglycerol acyltransferase metabolic pathway may contribute more to oil accumulation in walnut. 16 miRNA-mRNA regulatory modules related to walnut oil accumulation and fatty acid synthesis were constructed. 8 known miRNAs and 9 novel miRNAs regulate 28 genes involved in fatty acid (FA) metabolism and lipid synthesis. Among them, jre-miRn105, jre-miRn434, jre-miR477d and jre-miR156a.2 are key miRNAs that regulate walnut FA synthesis. Jre-miRn411 and jre-miR399a.1 are closely related to oil accumulation. These data provide new insights and lay the foundation for subsequent studies on walnut FA synthesis and oil accumulation.

A morel improved growth and suppressed Fusarium infection in sweet corn.

A post-fire morel collected from Populus simonii stands in Mt. Qingling was identified as Morchella crassipes Mes-20 by using nuclear ribosomal DNA internal transcribed spacer phylogeny. It was inoculated into sweet corn to observe colonized roots in purified culture and in greenhouse experiments. The elongation and maturation zones of sweet corn were remarkably colonized at the cortex intercellular and intracellular cells, vessel cells, and around the Casparian strip, forming ectendomycorrhiza-like structures. Colonization was also observed in the zone of cell division proximal to the root cap. Greenhouse assays with sweet corn showed that this morel stimulated the development of the root system and significantly increased the dry root biomass. M. crassipes also significantly reduced the incidence of Fusarium verticillioides in the kernels of mature ears when inoculated into young ears before Fusarium inoculation and prevented Fusarium infection in corn ears compared with that of the control in the greenhouse. When grown under axenic conditions, M. crassipes produced the phytohormones abscisic acid, indole-3-acetic acid, and salicylic acid. The benefits to plants elicited by M. crassipes may result from these phytohormones which may improve the drought resistance, biomass growth and resistance to Fusarium.

Luteodorsum huanglongense (Gomphaceae, Gomphales), a New Genus and Species of Gomphoid Fungus from the Loess Plateau, Northwest China.

During an investigation of the macrofungal flora in the Huanglong Mountains of the Loess Plateau, northwest China, a unique gomphoid fungus was discovered and collected. After morphological identification and molecular phylogenetic analyses, a new genus named Luteodorsum and its type species, L. huanglongense, were proposed. Phylogenetic analyses were conducted using datasets of nuclear ribosomal DNA 28S large subunit (LSU), mitochondrial (mt) adenosine triphosphatase (ATPase) subunit 6 (atp6), and mt small-subunit rDNA (mtSSU). The results confirmed that L. huanglongense forms an independent clade within Gomphales, with full maximum likelihood bootstrap support (MLBS), maximum parsimony bootstrap support (MPBS), and Bayesian posterior probability (BPP). L. huanglongense is characterized by its sandy-brown, orange-brown, or coffee-brown color; clavate to infundibuliform shape; wrinkled and ridged hymenophore; ellipsoid to obovoid warted basidiospores; cylindrical to clavate flexuous pleurocystidia; and crystal basal mycelium. Overall, this study contributes to the growing body of knowledge on the diversity and evolution of Gomphales and provides valuable insights into the unique fungal flora found in the Huanglong Mountains.

Multinuclei Occurred Under Cryopreservation and Enhanced the Pathogenicity of Melampsora larici-populina.

Melampsora larici-populina is a macrocyclic rust, and the haploid stage with two nuclei and the diploid of mononuclear sequentially occur annually. During the preservation of dry urediniospores at -80°C, we found that one isolate, ΔTs06, was different from the usual wild-type isolate Ts06 at -20°C because it has mixed polykaryotic urediniospores. However, the other spores, including the 0, I, III, and IV stages of a life cycle, were the same as Ts06. After five generations of successive inoculation and harvest of urediniospores from the compatible host Populus purdomii, the isolate ΔTs06 steadily maintained more than 20% multiple nucleus spores. To test the pathogenesis variation of ΔTs06, an assay of host poplars was applied to evaluate the differences between ΔTs06 and Ts06. After ΔTs06 and Ts06 inoculation, leaves of P. purdomii were used to detect the expression of small secreted proteins (SSPs) and fungal biomasses using quantitative real-time PCR (qRT-PCR) and trypan blue staining. ΔTs06 displayed stronger expression of five SSPs and had a shorter latent period, a higher density of uredinia, and higher DNA mass. A transcriptomic comparison between ΔTs06 and Ts06 revealed that 3,224 were differentially expressed genes (DEGs), 55 of which were related to reactive oxygen species metabolism, the Mitogen-activated protein kinase (MAPK) signaling pathway, and the meiosis pathway. Ten genes in the mitotic and meiotic pathways and another two genes associated with the "response to DNA damage stimulus" all had an upward expression, which were detected by qRT-PCR in ΔTs06 during cryopreservation. Gas chromatography-mass spectrometry (GC-MS) confirmed that the amounts of hexadecanoic acid and octadecadienoic acid were much more in ΔTs06 than in Ts06. In addition, using spectrophotometry, hydrogen peroxide (H2O2) was also present in greater quantities in ΔTs06 compared with those found in Ts06. Increased fatty acids metabolism could prevent damage to urediniospores in super-low temperatures, but oxidant species that involved H2O2 may destroy tube proteins of mitosis and meiosis, which could cause abnormal nuclear division and lead to multinucleation, which has a different genotype. Therefore, the multinuclear isolate is different from the wild-type isolate in terms of phenotype and genotype; this multinucleation phenomenon in urediniospores improves the pathogenesis and environmental fitness of M. larici-populina.

High diversity of Morchella and a novel lineage of the Esculenta clade from the north Qinling Mountains revealed by GCPSR-based study.

China is a mainland country rich in natural morel recourses, having records of half of the worldwide 61 morel phylospecies. In this study, 31 collections of ascocarps from the north Qinling Mountains, 4 collections of commercial cultivars from the south Qinling Mountains, and 3 Morchella mycelium clones from commercial cultivars were investigated using the genealogical concordance phylogenetic species recognition (GCPSR) method. Maximum-likelihood was employed for the construction of phylogenetic trees. A total of five phylogenetic species were found among the 38 collections, namely Morchella sp. Mes-8, Mes-9, Mes-13, and Mes-25, and Morchella chensiensis (IF556780), in addition to the false morel (Verpa bohemica). The identification of cultivated Morchella sp. Mel-2, Mel-6, Mel-10, and Mel-12 coincided with that of the commercial farms. A total of 80% (4/5) of yellow morels were new records for the Qinling region, except Mes-19; moreover, a novel monophyletic lineage, Morchella chensiensis, was found to be distinct from the previously reported phylospecies by single gene and combined genes analysis, thus being herein proposed as a new phylospecies. All collections from this study showed continental endemism, and all Qinling Mountains collections were grouped together in rDNA phylogenetic trees. The study provided insights on biodiversities in this key region of China.

Three new species of Talaromyces sect. Talaromyces discovered from soil in China.

Three new Talaromyces species isolated from soil are reported here, namely T. dimorphus (ex-type strain AS3.15692 T), T. lentulus (ex-type strain AS3.15689 T) and T. mae (ex-type strain AS3.15690 T). T. dimorphus is characterized by biverticillate and monoverticillate penicilli, ampulliform phialides, slimy texture with sparse mycelial funicles and absent conidiogenesis on MEA. T. lentulus is featured by vivid yellow mycelium on Cz and MEA, absent conidiogenesis on CYA, and globose smooth-walled conidia. T. mae presents sparse conidia on CYA and YES, funiculous and floccose texture on MEA, and ovoid smooth-walled conidia. Both morphological and molecular characters show that T. dimorphus is unique and has no close relatives. Although T. lentulus and T. mae resembles T. adpressus and T. pinophilus very much, phylogenetic analyses of CaM, BenA, ITS and Rpb2 sequences all support their status as novel species.

The complete chloroplast genome of the southern Chinese pine Pinus tabuliformis (Pinales: Pinaceae).

The complete nucleotide sequence of Pinus tabuliformis chloroplast genome (cpDNA) was carried out using Illumina Hiseq 2500. The genome is 119 646 bp in length, and the overall base composition of H-strand is 30.6% for A, 19.3% for C, 19.2% for G and 30.9% for T. There are 116 genes in the cpDNA, including 74 protein-coding genes, four ribosomal RNA genes (four rRNA species), and 36 transfer RNA genes (20 tRNA species). Phylogenetic analyses of P. tabuliformis and other 12 species belonging to Pinales were carried out using MEGA 6.0 with Neighbor-Joining methods. The sequences of P. tabuliformis were clustered in subfamily Pinaceae.

The complete chloroplast genome of the Juglans regia (Juglandales: Julandaceae).

The complete nucleotide sequence of Juglans regia chloroplast genome (cpDNA) was carried out using Illumina Hiseq 2500. The genome is 160 537 bp in length, and the overall base composition of H-strand is 31.59% for A, 18.35% for C, 17.76% for G and 32.30% for T. Similar to the other higher plants, cpDNA have a large single copy (LSC) region of 90 059 bp and a small single copy(SSC) of 18 412 bp, is separated by a pair of inverted repeats (IRa and IRb) of 26 033 bp. There are 113 genes in the cpDNA, including 80 protein-coding genes, 4 ribosomal RNA genes (4 rRNA species), 36 transfer RNA genes (19 tRNA species). To further investigate the evolution status of J. regia in the level of chloroplast genome, tree constructed using MEGA 6.0 with NJ and ML methord demonstrated J. regia was clustered in Fagales, which was identical with APG III.

[Genetic diversity of Melampsora larici-populina].

By using ITS - nrDNA-RELP, ITS sequencing, and RAPD molecular marker, this paper studied the genetic diversity of 11 isolates in 5 races of Melampsora larici-populina from different regions. The results indicated that the genetic differentiation of M. larici-populina was correlated to its geographical distribution, which could be grouped into northern and western geographic populations, and the latter could be grouped into high-mountain forest ecologic type (HMF) and western plain ecologic type (WPL). The genetic differentiation of the race was not always corresponded with the pathogenic one. T test manifested that the genetic diversity of the 5 races had no statistic difference in RAPD markers, and the diversity index of HMF was 0.5172, being slightly higher than that of WPL (0.5089). The ITS sequence of ribosome DNA was strictly conservative, and not suitable for the genetic diversity study of M. larici-populina intra-species populations.