In vitro regeneration of triploid from mature endosperm culture of Passiflora edulis "Mantianxing".

The regeneration of shoots from endosperm tissue is a highly effective method to obtain triploid plants. In this study, we elucidated the establishment of an in vitro regeneration system from endosperm culture for the production of Passiflora edulis "Mantianxing." The highest callus induction rate (83.33%) was obtained on the media supplemented with 1.0 mg/L TDZ. Meanwhile, the MS medium containing 1.0 mg/L 6-BA and 0.4 mg/L IBA gave the optimum 75% shoot bud induction. Chromosome analysis revealed that the chromosomal count of P. edulis "Mantianxing" regenerated from endosperm tissues was 27 (2n = 3x = 27), which indicated that shoots regenerated from endosperm tissues were triploids. Triploid P. edulis had more drought resistance than diploid plants. Our study provided a method for breeding of passion fruit by means of a stable and reproducible regeneration system from endosperm culture, leading to the generation of triploid plants.

QTL mapping for growth-related traits by constructing the first genetic linkage map in Simao pine.

BACKGROUND: Simao pine is one of the primary economic tree species for resin and timber production in southwest China. The exploitation and utilization of Simao pine are constrained by the relatively lacking of genetic information. Construction a fine genetic linkage map and detecting quantitative trait locis (QTLs) for growth-related traits is a prerequisite section of Simao Pine's molecular breeding program. RESULTS: In our study, a high-resolution Simao pine genetic map employed specific locus amplified fragment sequencing (SLAF-seq) technology and based on an F1 pseudo-testcross population has been constructed. There were 11,544 SNPs assigned to 12 linkage groups (LGs), and the total length of the map was 2,062.85 cM with a mean distance of 0.37 cM between markers. According to the phenotypic variation analysis for three consecutive years, a total of seventeen QTLs for four traits were detected. Among 17 QTLs, there were six for plant height (Dh.16.1, Dh16.2, Dh17.1, Dh18.1-3), five for basal diameter (Dbd.17.1-5), four for needle length (Dnl17.1-3, Dnl18.1) and two for needle diameter (Dnd17.1 and Dnd18.1) respectively. These QTLs individually explained phenotypic variance from 11.0-16.3%, and the logarithm of odds (LOD) value ranged from 2.52 to 3.87. CONCLUSIONS: In our study, a fine genetic map of Simao pine applied the technology of SLAF-seq has been constructed for the first time. Based on the map, a total of 17 QTLs for four growth-related traits were identified. It provides helpful information for genomic studies and marker-assisted selection (MAS) in Simao pine.

The complete chloroplast genome of Pinus densata.

Here, we report the complete chloroplast (cp) genome of Pinus densata. The complete chloroplast genome is 119,617 bp in length. There were 112 genes in the genome, including 73 protein-coding genes, 35 tRNA genes, and 4 rRNA genes. The overall GC was 38.5%, and the base of A, C, G, and T were 30.6, 19.3, 19.2, and 30.9%, respectively. Phylogenetic analysis showed that P. densata was relatively closely related to Pinus tabuliformis. These data may providing useful information for the phyletic evolution of P. densata within the Pinaceae family.

The complete chloroplast genome of Keteleeria evelyniana.

Here, we report the complete chloroplast genome of Keteleeria evelyniana. The genome is 116,940 bp in size, which is comprised of a large single-copy (LSC) region of 74,075 bp, a small single-copy (SSC) region of 40,425 bp, and two short inverted repeat (IR) regions of 1,220 bp. The overall GC content of the plastome was 38.5%. The new sequence comprised 103 unique genes, including 74 protein-coding genes, 4 rRNA genes, and 25 tRNA genes. Phylogenetic analysis showed that K.evelyniana was close to Keteleeria hainanensis and Keteleeria davidiana.

The complete chloroplast genome of a Cladrastis yunchunii X.W.Li et G.S.

Cladrastis yunchunii X.W.Li et G.S is a plant species belonged to the family Papilionaceae. Cladrastis yunchunii is currently found in broad-leaved forests in the limestone area of Luxi County, Yunnan Province. It is suitable for afforestation and urban greening in limestone areas. In this study, for the first time, we report the complete chloroplast genome sequence of C. yunchunii. We sequenced and assembled the entire chloroplast genome of C. yunchuniii. The chloroplast genome was determined to be 158,250 bp in length. It contained large single-copy (LSC) and small single-copy (SSC) regions of 84,930 bp and 12,664 bp, respectively, which were separated by a pair of inverted repeats (IR) regions of 30,328 bp. The genome contained 132 genes, including 87 protein-coding genes, 8 rRNA genes, and 37 tRNA genes. The overall GC content of the whole genome is 38.1%, and the corresponding values of the LSC, SSC, and IR regions were 36.4%, 33.6%, and 41.3%, respectively. Phylogenetic analysis suggested that C. yunchunii is closely related to the genus Ormosia in the Papilionaceae.

The complete chloroplast genome of Catalpa fargesii Bur. f. duclouxii (Dode) Gilmour.

In this study, we reported and characterized the complete chloroplast genome sequence of Catalpa fargesii Bur. f. duclouxii (Dode) Gilmour. The chloroplast genome was determined to be 158,250 bp in length. It contained large single-copy (LSC) and small single-copy (SSC) regions of 84,929 bp and 12,663 bp, respectively, which were separated by a pair of 30,329 bp inverted repeat (IR) regions. The genome is predicted to contain 121 genes, including 78 protein-coding genes, 35 tRNA genes, and 8 rRNA genes. The overall GC content of the genome is 38.1%. A phylogenetic tree reconstructed by 12 chloroplast genomes reveals that C. fargesii is mostly related to Catalpa. ovata and Catalpa. speciosa. This study identified the unique characteristics of the C. fargesii cp genome, which will provide a theoretical basis for species identification and biological research.

The complete chloroplast genome of Dipterocarpus turbinatus Gaertn. F.

Dipterocarpus turbinatus Gaertn. F., naturally distributes in Southern China, which is an elite natural tree with high economic and medicinal value. In study, all chloroplast (cp) genome of Dipterocarpus turbinatus Gaertn. F. was assembled and characterized based on Illumina pair-end sequencing data. The complete chloroplast genome length was 152,279 bp. It contained a large (LSC, 83,862 bp) and a small (SSC, 20,215 bp) single copy region, separated by a pair of inverted repeats of 24,101 bp (IRs). The overall GC content of genome was 37.3%, the corresponding values of LSC, SSC, and IR regions were 35.3, 31.6, and 43.2%, respectively. There were 128 genes in the genome including 84 protein-coding genes, 36 tRNA genes, and 8 rRNA genes. Among all genes, 14 genes contain a single intron and 1 gene has two introns. The result showed that Dipterocarpus turbinatus Gaertn. F. was closely related to Vatica mangachapoi.

Identification and characterization of microsatellite markers in Pinus kesiya var. langbianensis (Pinaceae).

PREMISE OF THE STUDY: Microsatellite primers were developed in Pinus kesiya var. langbianensis (Pinaceae), a species native to southwestern China, to investigate its genetic diversity and population structure in order to provide information for the conservation and management of this species. METHODS AND RESULTS: Using next-generation sequencing, a total of 2349 putative simple sequence repeat primer pairs were designed. Eighteen polymorphic markers in 60 individuals belonging to four populations of P. kesiya var. langbianensis were identified and characterized with two to 11 alleles per locus. The observed and expected heterozygosity ranged from 0.000 to 0.800 and 0.000 to 0.840, respectively. Each of these loci cross-amplified in the closely related species P. massoniana, P. densata, P. tabuliformis, and P. yunnanensis, with one to seven alleles per locus. CONCLUSIONS: The new markers are promising tools to study the population genetics of P. kesiya var. langbianensis and related species.

Growth promotion of Yunnan Pine early seedlings in response to foliar application of IAA and IBA.

A field experiment was conducted using a 3 × 3 orthogonal regression design to explore the growth promotion of one-year-old Yunnan pine seedlings (Pinus yunnanensis Franch.) in response to foliar application of IAA (indole-3-acetic acid) at rates of 0, 200 and 400 mg·L(-1) and IBA (indole-3-butyric acid) at rates of 0, 200 and 400 mg·L(-1) in order to promote the growth during the seedlings' early stage. The experiment was conducted at the Lufeng Village Forest Farm of Yiliang County in Kunming, Yunnan, China. The results showed that IAA and IBA were effective in growth promotion of Yunnan pine seedlings. The response of both growth increment and biomass accumulation to the concentration of IAA and IBA can be modeled using a bivariate surface response, and each growth index had a peak value. Growth indexes increased with the increase of the dosage of photohormones before reaching a peak value, and then decreased. The different growth indexes had various responses to the concentrations and ratio of IAA and IBA. The foliar application of IAA in combination with IBA showed the largest improvement on the biomass of the needles, followed by stems and roots. The higher ratio of IAA promoted stem diameter growth, root system development and biomass accumulation in the needles, while a higher ratio of IBA contributed to height growth and biomass accumulation in the stem. Based on the auxin effect equations on the different growth indexes and surface response, the optimum concentrations and the (IAA:IBA) ratios can be obtained. The optimum concentrations of IAA and IBA were 167 and 186, 310 and 217, 193 and 159, 191 and 221, and 206 and 186 mg·L(-1), with corresponding ratios of 1:1.11, 1:0.70, 1:0.82, 1:1.15 and 1:0.90, respectively, at the maximum seedling height and collar diameter growth as well as biomass accumulation at the root, stem and needle. The above growth indexes were 22.00%, 79.80%, 48.65%, 82.20% and 107.00% higher than the control treatment.