You are looking at 1 - 10 of 32 items for
- Author or Editor: Li Lu x
Acer truncatum seeds are an excellent source of beneficial natural compounds, including high levels of unsaturated fatty acids (UFAs), that promote health. Recently, A. truncatum has emerged as an oil crop. Therefore, the transcriptomes of A. truncatum seeds at 70, 85, 100, 115, 145, 180 days after flowering (DAF) were analyzed to gain a better understanding of the transcriptional and translational regulation of seed development and oil biosynthesis. A total of 28,438 genes were identified, and 3069/2636, 3288/3438, 1319/2750, and 5724/5815 upregulated/downregulated genes were identified when comparing different samples with 85 DAF seeds. Sixteen lipid metabolism pathways with 754 differentially expressed genes (DEGs) were identified, including 34 DEGs associated with UFA biosynthesis. A phylogenetic analysis revealed that six putative fatty acid desaturase (FAD) genes clustered into five FAD groups. A quantitative real-time polymerase chain reaction analysis indicated that the temporal expression patterns of oil biosynthesis genes and transcription factors were largely similar to the RNA sequencing results. The results of this study will enhance the current understanding of oil metabolism in A. truncatum seeds and allow new methods of improving oil quality and seed yield in the future.
To understand the relationship between fruit cracking and gene expression patterns, we identified two expansin genes from litchi (Litchi chinensis Sonn.) fruit and then examined their expression profiles in pericarp and aril at different stages of fruit development, using the cracking-resistant cultivar Huaizhi and the cracking-susceptible cultivar Nuomici. Two full-length cDNAs of 1087 and 1010 base pairs encoding expansin, named LcExp1 and LcExp2, were isolated from expanding fruit using RT-PCR and RACE-PCR (rapid amplification of cDNA ends) methods. LcExp1 mRNA could be detected from the early stage of fruit rapid growth (59 days after anthesis). The LcExp1 mRNA increased and reached to the highest level at the end of growth phase (80 days after anthesis) in pericarp of `Huaizhi', while the mRNA could be detected at the stage of rapid fruit growth, then increased slightly and finally kept remained almost constant in the pericarp of `Nuomici'. Similar accumulation of LcExp2 mRNA was observed in fruit aril of `Nuomici' and `Huaizhi', whereas LcExp2 accumulated only in pericarp of `Huaizhi' but did not appear in pericarp of `Nuomici'. The results indicate that expression of two expansin genes in litchi pericarp are closely associated with fruit growth and cracking.
Hami melon ‘Queen’ (Cucumis melo ssp. melo var. ameri Pangalo) is the most widely cultivated and exported type of melon in Xinjiang Province, Northwest China. We previously found the unique traits of Hami melon ‘Queen’ for wave seeds and tight-placenta fruits. An analysis of the inheritance showed that these traits were controlled by two recessive genes wave seed (ws) gene and tight-placenta (tp) gene, respectively. Here, to identify these two traits and melon seed–related traits, segregation populations including BC1 and F2 derived from a cross between ‘Queen’ (P1) and MR-1 (P2) were used as mapping populations. Eighty-seven simple sequence repeat (SSR) markers were used in map construction of BC1P1 population, and as a result, ws and tp were identified on linkage group 1. Analysis of quantitative trait locus (QTL) referring seed traits showed that QTL ss1.1 for seed shape (SS) and QTL sl1.1 for seed length (SL) were located at LG 1, supported by likelihood of odds (LODs) of 15.6 and 13.4, respectively, and both linked with ws. Subsequently, the genetic linkage and parental re-sequence analysis were constructed for fine mapping ws and tp. Genetic analysis showed that ws and tp were located in CM3.5_scaffold00060 on LG 1, flanked by InDelchr1-3241 and InDelchr1-3233. The 80.9-kb physical distance of this region included 11 candidate genes. Among them, MELO3C023549 and MELO3C023551 could be candidates for ws and tp by sequence alignment and allelic variation survey in parental lines. MELO3C023549 was predicted to encode an MYB46-like transcription factor related to positive regulation of secondary cell wall biogenesis. MELO3C023551 was annotated to encode a cellulose synthase A (CESA) associated with cellulose biosynthetic process.
Early production and high energy efficiency are important in greenhouse vegetable production in cold regions. A dynamic temperature integration strategy with low pre-night temperature (PNT) has been developed to reduce energy consumption and to improve early fruit yield and energy use efficiency. However, the application of this temperature control strategy is feasible only if there is no crop yield and quality loss. To determine the low PNT tolerance threshold and explore the mechanism of this temperature control strategy on plant growth and development, the effects of four PNT temperature integration treatments (PNT9, PNT11, PNT13, and PNT15, with an actual PNT of 9.4, 11.3, 13.3, and 15.1 °C, respectively) on greenhouse tomatoes (Solanum lycopersicum) were investigated. The PNT was applied at the beginning of the night for 3 h, whereas temperatures in other periods during a day (24 h) were adjusted accordingly to ensure the same 24-h average temperature (19.4 °C) for all PNT treatments. Four cultivars (Bigdena, Clarance, Quest, and Conchita), representing all three types (beefsteak, cluster, and cherry) of greenhouse tomatoes, were used in the study. The optimum PNT for fruit yield was 13.8 and 14.9 °C for ‘Bigdena’ and ‘Conchita’, respectively. Low PNT down to 11 °C did not compromise fruit yield and plant development in ‘Clarance’, and thus a PNT lower than 13 °C can be used for ‘Clarance’ if it does not have a negative effect on fruit quality. In ‘Bigdena’ and ‘Conchita’, the above-ground biomass increased with increasing PNT at the low range of PNT, peaked at ≈13 °C PNT (13.7 and 13 °C for ‘Bigdena’ and ‘Conchita’, respectively), then declined at high PNT. Leaf photosynthesis rates were increased by the highest PNT (PNT15), whereas respiration rates were reduced by the lowest PNT (PNT9). Therefore, PNT at ≈13 °C might have allowed for the proper balance between the high photosynthesis for photoassimilate generation and the low respiration for photoassimilate conservation and thus accumulated the highest photoassimilate and the highest fruit yield in ‘Bigdena’. Flower development rate in ‘Conchita’ decreased linearly with low PNT, which might have limited the response of its fruit yield to low PNT and raised the optimum PNT for fruit yield to 14.9 °C. Temperature integration with proper low PNT can be an effective climate control strategy for increasing early fruit yield and energy use efficiency in greenhouse tomato production.
The resurrection plant Selaginella pulvinata (Hook. & Grev.) Maxim is used as an ornamental and medicinal plant. It is also a good candidate for exploring the desiccation tolerance of resurrection plants. However, there is not an efficient propagation method for S. pulvinata. In the present study, we evaluated the establishment of in vitro propagation of S. pulvinata using frond tips as explants. The original shoot induction, adventitious shoot proliferation and plantlet growth media, and substrate type of plantlet acclimatization were investigated. The highest induction rate of original shoots (61.77 ± 5.17%) was obtained on half-strength (1/2) MS medium supplemented with 0.1 mg·L−1 N6-benzylaminopurine (BAP). The 1/2 MS with 1.0 mg·L−1 BAP was the most effective medium for the adventitious shoot proliferation. The quarter-strength (1/4) MS containing 0.1% (w/v) active charcoal (AC) was optimum for plantlets proliferated from adventitious shoots and plantlet growth. Approximately 98 plantlets could be obtained from one single original shoot via one-time shoot proliferation cultivation and plantlet cultivation. The acclimated plants on a 5:1 (v/v) mixture of peat and perlite had the highest survival rate (92.13 ± 1.67%). The acclimated plants maintained excellent resurrection ability.
Citrus species are among the most important fruit trees in the world and have a long cultivation history. However, until now, the exact genetic origins of cultivated Citrus such as sweet orange (Citrus sinensis), lemon (C. limon), and grapefruit (C. paradisi) have remained unidentified. In the present study, amplified fragment length polymorphism (AFLP) fingerprints, nuclear internal transcribed spacer (ITS), and three plastid DNA regions (psbH – petB, trnL – trnF, and trnS - trnG) of 30 accessions of the cultivated citrus and their putative wild ancestors were analyzed in an attempt to identify their paternal and maternal origins. Molecular phylogenetic trees were constructed based on the AFLP data, and chloroplast DNA and ITS sequences using the genus Poncirus as the outgroup. Our results indicated that bergamot (C. aurantifolia) and lemon were derived from citron (C. medica) and sour orange (C. aurantium), and grapefruit was a hybrid that originated from a cross between pummelo (C. grandis) and sweet orange. Rough lemon (C. limon) was probable as a parent of rangpur lime (C. limonia) and guangxi local lemon (C. limonia). Our data also demonstrated that sweet orange and sour orange were hybrids of mandarin (C. reticulata) and pummelo, while rough lemon was a cross between citron and mandarin. For mexican lime (C. aurantifolia), our molecular data confirmed a species of Papeda to be the female parent and C. medica as the male. These findings provide new information for future study on the taxonomy, evolution, and genetic breeding of Citrus.
Solid-state 1H-NMR and 13C-NMR spectroscopy were used to investigate the chemical components of sweet cherry tree leaves under rain-shelter cultivation (RS) and open-field cultivation (CK). The 1H-NMR spectral chemical shifts of RS and CK showed differences in height and integral value. The δ 1–3, δ 3–4, δ 4–6, and δ 6–10 regions were attributed to the hydrogen signals of aliphatic compounds, unsaturated carbohydrate compounds, and aromatic compounds, respectively. Among the four regions, the percentage of signal strength and the integral value of hydrogen signals of RS and CK were 34.25% and 28.34%, 11.64% and 12.26%, 26.71% and 31.06%, 27.4% and 28.34%, respectively. The 13C-NMR results showed that the CK sample had slightly stronger spectral lines and contained slightly more carbon atoms than the RS sample. Sweet cherry leaves contain aromatic and carboxyl carbons, mainly from carboxylic acids, esters, and amides. The alkyl carbons exhibited the lowest ratio, whereas the alkyl and alkoxy carbons were mainly derived from carbohydrates (cellulose, polysaccharides).
Light, as the energy and signal sources for plant growth and development, is one of the most important environment factors in recently developed plant factories with artificial light (PFALs). To find the optimal combination of light wavelengths for lettuce (Lactuca sativa cv. ‘Tiberius’) plant growth in a PFAL, four treatments, each using red (R; 662 nm) and blue light (B; 447 nm) with a ratio of 4:1 and photon flux density (PFD) of 150 μmol·m−2·s−1, and mixing, respectively, with 50 μmol·m−2·s−1 of green light (G; 525 nm; RBG), yellow light (Y; 592 nm; RBY), orange light (O; 605 nm; RBO) and far-red light (FR; 742 nm; RBFR), were set up during this experiment. A combination of R and B with a ratio of 4:1 and PFD of 200 μmol·m−2·s−1 was set as the control (RB). The responses of lettuce growth, morphology, anatomical structure of the lettuce leaf, photosynthetic performance, lettuce nutritional quality, and energy use efficiency were investigated. The results showed that RBG, RBO, and RBFR increased the shoot fresh weight of lettuce by 20.5%, 19.6%, and 40.4%, and they increased the shoot dry weight of lettuce by 24.2%, 13.4%, and 45.2%, respectively, compared with those under RB. The Pn under RBY was significantly lower than that under RB, although no significant differences in chlorophyll or carotenoid content were found between RBY and RB. RBG increased the lettuce leaf area, the thickness of the leaf palisade tissue, Pn, and light use efficiency compared with those under RB. Plants grown under RBO showed better photosynthetic capacity, such as higher Pn, ΦPSII, and other photosynthetic parameters. RBFR caused an increase in lettuce leaf area and energy use efficiency, but a decrease in leaf thickness and Pn of the single leaf. Moreover, tipburn injury was observed under RBFR. Therefore, these results demonstrate that RBG and RBO can be considered optimal combinations of light wavelengths for lettuce growth in a PFAL in this experiment, although plant growth can also be improved by using RBFR.
Kalanchoe (Kalanchoe blossfeldiana) is a common potted flower that is popular throughout the world. Brown spot (caused by Stemphylium lycopersici) is one of the common foliage diseases in kalanchoe. This disease tends to infect leaves of kalanchoe plants in hot and humid environments, reducing their aesthetic value. The current investigation aimed to generate mutations resistant to brown spot in ‘Mary’ kalanchoe through chemical mutagenesis followed by molecular marker identification. Putative mutants were developed by treating embryogenic calluses with ethyl methanesulfonate (EMS) at median lethal doses (LD50)–either a 0.8% concentration for 2 hours or a 1.0% concentration for 0.5 hours. Brown spot crude toxin solution was used as the selection agent to identify disease-resistant calluses during tissue culture. The optimal crude concentration (60%) was determined by soaking calluses with different concentrations of crude pathogen: 0%, 20%, 40%, 60%, and 80% (v/v). A total of 32 anti-brown spot lines were regenerated and tested for disease resistance with detached leaves. Three regenerated EMS mutant lines showed no obvious brown spot lesions on their leaves after the disease resistance assay and were subjected to polymorphism identification by start codon targeted (SCoT) molecular markers. Three (SCoT40, SCoT71, and SCoT72) of 45 selected primers were chosen to identify the mutants. This work may lay the foundation for further development of new disease-resistant cultivars of kalanchoe.
Many reports indicate that an abundance of really interesting new gene (RING) play key roles in regulating defense responses against abiotic and biotic stresses in plants. In this study, the cloning and functional characterization of a RING gene, MaRING2, in banana (Musa acuminata) fruit are reported. MaRING2 belongs to the NEP1-interacting protein (NIP) RING-H2 finger protein family. Gene expression profiles revealed that MaRING2 was cold responsive and induced by abscisic acid (ABA) treatment during cold storage. In this study, the MaRING2 under control of the Cauliflower mosaic virus 35S (CaMV 35S) promoter was transformed to tobacco (Nicotiana benthamiana) using agrobacterium (Agrobacterium tumefaciens)-mediated transformation. The resultant MaRING2-overexpressing transgenic plants (35S:MaRING2) exhibited significantly increased tolerance to low temperatures and were hypersensitive to exogenous ABA in terms of germination and early seedling growth. In addition, overexpression of MaRING2 enhanced the expression of stress-responsive genes under normal (before cold stress) or cold conditions. These results demonstrate the biological role of MaRING2 in conferring cold tolerance. Taken together, these results suggest that MaRING2, a C3H2C3-type RING protein, is a positive regulator of the ABA-dependent stress response.