Millions of years of isolation have given Madagascar a unique flora that still reflects some of its relationship with the continents of Africa and India. Here, the complete chloroplast sequence of Beilschmiedia moratii, a tropical tree in Madagascar, was determined. The plastome, with a length of 158,410 bp, was 143 bp and 187 bp smaller than those of two closely related species, B. pierreana and Potameia microphylla, in sub-Saharan Africa and Madagascar with published sequences, respectively. A total of 124 repeats and 114 simple sequence repeats (SSRs) were detected in the plastome of B. moratii. Six highly variable regions, including ndhF, ndhF-rpl32, trnC-petN, pebE-petL, rpl32-trnL, and ycf1, among the three African species were identified and 1151 mutation events, including 14 SVs, 351 indels, and 786 substitutions, were accurately located. There were 634 mutation events between B. moratii and P. microphylla with a mean nucleotide variability (π) value of 0.00279, while there were 827 mutation events between B. moratii and B. pierreana with a mean π value of 0.00385. The Ka/Ks ratios of 86 protein-coding genes in the three African species were less than 1, and the mean value between B. moratii and P. microphylla was 0.184, while the mean value between B. moratii and B. pierreana was 0.286. In this study, the plastid genomes of the three African Beilschmiediineae species were compared for the first time and revealed that B. moratii and P. microphylla from Madagascar were relatively conserved, with low mutation rates and slower evolutionary rates.

PurposeTo excavate genes related to the number of cones in Pinus armandii. MethodsBased on the phenotypic data of cone number of P. armandii, the high and low cone number individual plants were screened. Combined with phenotypic data, single-nucleotide polymorphism (SNP) markers developed previously were used to genome-wide association study (GWAS), and the phylogenetic tree of P. armandii samples was constructed, the SNP markers and candidate genes related to cone number of P. armandii were excavated, and the tissue-specific expression of qPCR gene was further analyzed in six parts of P. armandii, such as needles, xylem, phloem, bark, young cones and roots. ResultsThe phylogenetic tree showed that the individual plants of the same provenance were basically in a similar position, while the individual plants from Weishan were widely distributed in each population, which was basically consistent with the results of principal component analysis. A total of 12 SNP loci significantly associated with cone number were detected by GWAS. It was found that the sequence of Marker193307 was highly similar to the cellulose synthesis related gene Korrigan (KOR1, encoding transmembrane endo-β-1,4-D glucanase) (74.74%). The tissue-specific expression of qPCR results showed that the expression level of the gene was the highest in the phloem of branches, followed by the young cones, and the least in the roots. It was preliminarily judged that the gene was related to the number of cones. ConclusionP. armandii provenance close to the individual basically in a similar position. The materials of Weishan provenance have more extensive genetic variation than other provenances. GWAS only retrieves one gene (KOR1) related to plant cellulose synthesis, which may be involved in the expression of cone number.

氨磺灵是一种三硝基苯胺类除草剂,在应用于植物多倍体的诱导中,取到了较好的诱导效果.本研究以氨磺灵为诱变剂,采用混培法对来自 3 个不同地点的滇杨材料进行多倍体诱导,探讨氨磺灵对滇杨的多倍化诱导效果,继而对诱导后的材料进行同质化处理,鉴定其倍性.结果显示:氨磺灵可诱导滇杨产生多倍体材料,变异率最高的处理组合为预培养 4 d后,在添加 50 mg/L氨磺灵的分化培养基(1/2 MS+TDZ 0.01mg/L+NAA 0.01mg/L)中培养 2 d,变异率可达 28.57%.多倍体植株与正常株形态差异明显,且染色体数目增加为 76 条,多倍体滇杨的荧光通道值约为二倍体滇杨的 2 倍,表明滇杨材料已加倍为四倍体.研究结果对滇杨乃至木本植物的多倍体育种具有重要的理论及实践意义.

Objective Means utilizing molecular markers to differentiate rapidly and accurately male and female Populus yunnanensis plants at young stages was investigated. Method Using simple sequence repeats (SSR), molecular markers were screened for those might associate with the sex of P. yunnanensis at seedling stages and before flowering. Result Fifteen pairs of SSR primers were selected from the reported literatures. One of them, coded BPCA90, showed clear bands and stable reaction in agarose gel detection. After rescreening the primer by polyacrylamide gel electrophoresis, a specific band of approximately 680 bp appeared in the PCR amplification of male P. yunnanensis. Subsequent testing on 30 plants using these SSR primers showed significantly more males than females in a ratio of 13 to 2. ConclusionShort of a visible morphological sign for the determination, the SSR primers screened by this study appeared to suffice the general purpose of differentiating the sex of P. yunnanensis at early growth stage.

Mangifera plants are tropical fruits that have high economic value and scientific utility. However, the chloroplast genome characteristics and phylogenetic relationships among Mangifera species remain unclear. In this work, we reconstructed maximum likelihood (ML) and Bayesian inference (BI) phylogenetic trees using 11 newly sequenced chloroplast genomes as well as six existing genomes obtained from the National Center for Biotechnology Information (NCBI) database. The chloroplast genomes all had a typical quadripartite structure, with lengths ranging from 157,368 to 158,942 bp. The GC-content in the genomes ranged from 37.8% to 37.9%. We found conserved boundaries comprised of two inverted repeats (IRs), large single-copy (LSC) regions, and small single-copy (SSC) regions. Nucleotide polymorphism analysis revealed three hypervariable regions (ycf4-cemA, rps18-rpl20, and rpl32-ndhF) in the LSC and SSC regions, which could potentially be used as DNA barcodes for Mangifera species. According to our phylogenetic analysis, Mangifera plants were clustered into three clades. Among them, all five samples of M. indica formed a monophyletic group in Clade Ⅰ. Clade Ⅱ included seven Mangifera species and could be further divided into five subclades with 100% branch support values. Clade Ⅲ included two M. persiciforma samples that formed a monophyletic group. Taken together, these results provide a theoretical basis for species determination, in addition to shedding light on the evolution of Mangifera.

Neocinnamomum plants are evergreen shrubs or small trees belonging to the Neocinnamomeae tribe of the Lauraceae family. Their seeds are rich in fatty acids, and their leaves are often used in traditional Chinese medicine. Presently, only a few studies have been performed on Neocinnamomum plants; therefore, the genome-based phylogeny among Neocinnamomum species has not been determined, which limits the germplasm innovation of this genus. In this study, by the Illumina (next-generation sequencing) and third-generation sequencing technologies, the whole genomes of seven Neocinnamomum species samples were sequenced, their nuclear DNA (nrDNA) sequences were assembled and characterized, and their phylogeny was reconstructed. The results revealed four hypervariable regions (i.e. transcribed spacer regions) in the nrDNA sequences, among which the highest degree of variation was observed in the external transcribed spacer (ETS) region localized behind the 26S gene. A total of 27 insertions/deletions and 184 single-nucleotide polymorphisms, both localized mainly in the ETS and internal transcribed spacer regions, were identified. Phylogenetic trees were constructed based on the nrDNA sequences using the maximum likelihood (ML) and Bayesian inference (BI) methods with Caryodaphnopsis henryi as the outgroup. The ML tree divided the seven Neocinnamomum species into four clades. Clade I consisted of Neocinnamomum caudatum var. macrocarpum and Neocinnamomum caudatum , clade II included Neocinnamomum delavayi and Neocinnamomum mekongense , clade III included Neocinnamomum fargesii and a branch species of N. delavayi and clade IV included Neocinnamomum lecomtei , constituting a monophyletic and basal group. The BI tree shared the same topological structure as the ML tree, and all the support values of the BI tree were one except for that of one Neocinnamomum species (0.98). The results of this study provide new evidence regarding the phylogenetic evolution of the Neocinnamomum plants.

为了解楚雄市国有林场樟檀林分场华山松无性系种子园中6个种源间生长性状的差异,在种子园内,随机选取96个无性系的5个重复,利用测高仪、测树围尺分别测量树高和胸径,共测量480个单株,并对不同华山松无性系优株的树高、胸径生长量进行方差分析.结果表明,华山松6个种源间树高和胸径存在显著差异;LSD多重比较结果显示,会泽种源树高平均值最高与楚雄和巍山种源存在显著差异,其他5个种源间树高差异不显著;会泽胸径平均值最高与宜良、南华、巍山、楚雄和腾冲种源差异显著,其他5个种源间胸径差异不显著,表明会泽种源的华山松在种子园内生长速度最快.研究结果可为无性系选育和木材加工提供重要理论和参考依据.

[目的]在滇杨幼苗时期和开花前利用形态差异对雌雄株进行性别鉴定极为困难,因此亟需探明对其性别进行快速鉴定的分子标记方法.[方法]以滇杨雌雄各 30株为材料,利用简单重复序列(SSR)筛选与滇杨性别相关的分子标记,并利用所获得的SSR标记对未知性别滇杨幼苗进行鉴定,分析滇杨苗期的性别分化情况.[结果]从已报道的相关文献中选出 15对与植物性别连锁的SSR引物,经试验筛选出 1对(BPCA90)在琼脂糖凝胶检测中显现清晰条带且反应稳定的SSR引物,并将这对引物经聚丙烯酰胺凝胶电泳进行复筛,经PCR扩增后在滇杨雄株中出现 1条特异性条带,大小在 680 bp左右.利用这对SSR引物对 30株滇杨幼苗进行性别鉴定,结果表明雄株明显多于雌株,且比例为 13∶2.[结论]试验筛选所得到的SSR引物可以用于滇杨早期进行性别鉴定.研究结果可作为滇杨早期性别鉴定的遗传标记,为今后滇杨在生产中的分性别利用提供技术支持.

The genus Neocinnamomum is considered to be one of the most enigmatic groups in Lauraceae, mainly distributed in tropical and subtropical regions of Southeast Asia. The genus contains valuable oilseed and medicinal tree species. However, there are few studies on the genus Neocinnamomum at present, and its interspecific relationship is still unclear. In order to explore the genetic structure and evolutionary characteristics of the Neocinnamomum chloroplast genome and to resolve the species relationships within the genus, comparative genomic and phylogenetic analyses were performed on the whole chloroplast genome sequences of 51 samples representing seven Neocinnamomum taxa. The whole Neocinnamomum chloroplast genome size ranged from 150,753-150,956 bp, with a GC content of 38.8%-38.9%. A total of 128 genes were annotated within the Neocinnamomum chloroplast genome, including 84 protein coding genes, 8 rRNA genes, and 36 tRNA genes. Between 71-82 SSRs were detected, among which A/T base repeats were the most common. The chloroplast genome contained a total of 31 preferred codons. Three highly variable regions, trnN-GUU-ndhF, petA-psbJ, and ccsA-ndhD, were identified with Pi values > 0.004. Based on the whole chloroplast genome phylogenetic tree, the phylogenetic relationships among the seven Neocinnamomum taxa were determined. N. delavayi and N. fargesii were the most closely related species, and N. lecomtei was identified as the most basal taxon. In this study, the characteristics and sequence variation of the chloroplast genomes of seven Neocinnamomum taxa were revealed, and the genetic relationship among the species was clarified. The results of this study will provide a reference for subsequent molecular marker development and phylogenetic research of Neocinnamomum.

Pourthiaea is of great ornamental value because it produces white flowers in spring and summer, red fruit in autumn, and their fruit does not fall in winter. In order to explore the genetic structure and evolutionary characteristics of the chloroplast genome of Pourthiaea, comparative genomics analysis and phylogenetic analysis were conducted using ten published chloroplast genomes of Pourthiaea from the NCBI database. The results showed that the chloroplast genomes of the ten species of Pourthiaea showed typical circular tetrad structures, and the genome sizes were all within the range of 160,159–160,401 bp, in which the large single copy was 88,047–88,359 bp, the small single copy was 19,234–19,338 bp, and the lengths of a pair of inverted repeats were 26,341–26,401 bp. The GC contents ranged from 36.5% to 36.6%. A total of 1017 SSR loci were identified from the chloroplast genomes of the ten species of Pourthiaea, including six types of nucleotide repeats. The gene types and gene distribution of the IR boundary regions of the chloroplast genomes of different species of Pourthiaea were highly conservative, with little variation. Through the sequence alignment of chloroplast genomes, it was found that the chloroplast genomes of the ten species of Pourthiaea were generally highly conservative. The variation mainly occurred in the spacer regions of adjacent genes. Through nucleic acid diversity analysis, three hypervariable regions were screened at Pi > 0.006, namely trnQ(UUC)-psbk-psbl, accD-psal, and ndhF-rpl32-trnL (UAG). Phylogenetic analysis showed that the ten species of the genus Pourthiaea were clustered in the same branch and formed sister groups with the genus Stranvaesia, and that the support rate for the monophyly of the genus Pourthiaea was high. This study can serve as a reference for the breeding, genetic evolution, and phylogeny of Pourthiaea.