Forestry research最新文献

Prunasin and amygdalin are important factors that influence the kernel taste of apricots, however, the regulatory mechanisms underlying this are unclear. In this study, we analyzed the phenotype and transcriptome of kernels during development in Prunus sibirica (bitter kernels) and Prunus armeniaca × Prunus sibirica (kernel consumption apricot, sweet kernels). Prunasin and amygdalin content was significantly higher in bitter kernels compared with that in sweet kernels. Prunasin content exhibited a decreasing trend in both bitter and sweet kernels. The fastest decline was observed in bitter and sweet kernels during S3-S4 (82.21%) and S2-S3 (59.65%), respectively. The amygdalin content in the bitter kernels exhibited the fastest increase between 45-60 d after flowering, and reached a peak at 6.22% on 60 d after flowering. In contrast, the peak in sweet kernels occurred at 60 d after flowering, with a much lower content of 0.18%. Transcriptome analysis revealed 6,942 differentially expressed genes (DEGs), with a subset of 38 DEGs specifically enriched in the cyanoamino acid metabolic pathway. Among these, the ten candidate genes, including CYP79, CYP71, UGT1, AH, and PH, were identified as crucial in regulating prunasin and amygdalin metabolism. Furthermore, a weighted gene co-expression network analysis (WGCNA) unveiled two modules that exhibited significant correlation with prunasin and amygdalin content. Five DEGs were located at the center of the co-expression network, and were identified as hub genes, with four positively regulating prunasin content and one negatively regulating amygdalin content. Our results provide novel insights into the molecular-level regulation of the apricot kernel taste.

DNA methylation plays a crucial role in the development of somatic embryos (SEs) through the regulation of gene expression. To examine the impact of DNA methylation on gene expression during early SE development in Picea glauca, the demethylation reagent 5-aza-dC (5-aza-2'-deoxycytidine) was employed to modify DNA methylation regions and levels during the pre-maturation stage of somatic embryogenesis. The application of 2.0 µM 5-aza-dC did not induce toxicity to SEs in early development. Following treatment, the global DNA methylation level decreased significantly on the 7^th day of pre-maturation and the 1^st week of maturation. Methylated DNA immunoprecipitation (MeDIP) sequencing revealed that differentially methylated regions, as analyzed through Gene Ontology (GO), were related to plant development and reproduction and that they were hypomethylated on the 3^rd day but hypermethylated on the 7^th day in 5-aza-dC-treated embryogenic tissues. These findings indicate that 5-aza-dC treatment positively impacts early SE development, which was inhibited following 7 d of treatment. The expression of MSH7, JMJ14, and CalS10 was associated with DNA methylation, epigenetic regulation, and somatic embryogenesis. Further analysis of methylated regions revealed that the expression profiles of MSH7, JMJ14, and CalS10 were correlated with altered DNA methylation, suggesting DNA methylation at 5 mC may play a role in controlling the expression of these genes and regulating the early development of SEs in P. glauca. This study offers new insights into the regulation of somatic embryogenesis in conifers.

Calcineurin B-like (CBL) proteins are a class of important Ca²⁺ receptors that play key roles in plant stress response. CBLs have been shown to participate in responses to abiotic stresses such as drought, salt, and cold in many plant species, including Arabidopsis and rice. However, little is known about their potential functions in the desert halophyte Nitraria tangutorum. Here, we have identified 11 CBL genes distributed across six chromosomes of N. tangutorum and categorized them into four groups through phylogenetic analysis. Synteny analysis showed that they have strong collinear relationships and have undergone purifying selection during their evolution. NtCBL promoter regions contain a variety of cis-acting elements related to hormone and environmental stress responses. Real-time quantitative PCR showed that the expression of NtCBLs differed significantly among various tissues and was upregulated by salt and drought stress. We chose NtCBL1-1 for an in-depth functional characterization and observed that transgenic Arabidopsis plants expressing NtCBL1-1 exhibited increased tolerance to both drought and salt stress. Compared to wild-type Arabidopsis, transgenic lines showed higher germination rates, slower chlorophyll degradation, more soluble proteins, and reduced accumulation of the oxidative stress marker malondialdehyde. These findings indicate that NtCBL1-1 plays a significant role in responding to drought and salt stress, laying the foundation for further investigations into the functional mechanisms of NtCBL genes in N. tangutorum.

Populus is a genus of 25-30 species of deciduous flowering plants in the family Salicaceae, which are primarily planted in short-rotation planations for producing timber, pulpwood, wooden products as well as bioenergy feedstock; they are also widely planted in agricultural fields and along roadsides as shelter forest belts for windbreak, decoration, and reduction of pollutants and noise. Moreover, their fast-growth and good adaptation to marginal lands enable them to provide some critical ecosystem services at various phytoremediation sites for land restoration and reclaimation. Thanks to their important roles, breeding for fast growing poplar trees has been one of the most important objectives for nearly a century. One of the most demonstrated, documented achievements in this aspect is polyploid breeding, especially triploid breeding. This paper critically reviews the various techniques used in inducing triploid plants, including natural 2n formation, artificial induction of 2n male and female gemmates through chemical or physical treatments, trait characterization of the triploid and tetraploid breeding populations, unveiling the molecular mechanisms underpinning the significantly improved traits, and identification and selection of the best triploid progenies. This review also recapitulated the challenges and strategies facing the future of triploid breeding in Populus, including amelioration of 2n gamete induction techniques and efficiency, selection of the best parents and identification of the best progrenies, utilization of the huge amount of genomic, transcriptomic, proteomic, metabolomic, and other omics data for selecting parents for improving target traits.

Young moso bamboo shoots are a popular seasonal food and an important source of income for farmers, with value for cultivation estimated at $30,000 per hectare. Bamboo also has great environmental importance and its unique physiology is of scientific interest. A rare and valuable phenomenon has recently appeared where a large number of adjacent buds within a single moso bamboo rhizome have grown into shoots. Although of practical importance for the production of edible shoots, such occurrences have not been scientifically studied, due to their rarity. Analysis of collected reports from enhanced shoot production events in China showed no evidence that enhanced shoot development was heritable. We report the analysis of the rhizosphere microbiome from a rhizome with 18 shoots, compared to rhizomes having one or no shoots as controls. The community of prokaryotes, but not fungi, correlated with the shoot number. Burkholderia was the most abundant genus, which was negatively correlated with rhizome shoot number, while Clostridia and Ktedonobacteria were positively correlated. Two Burkholderia strains were isolated and their plant-growth promoting activity was tested. The isolated Burkholderia strains attenuated the growth of bamboo seedlings. These data provide the first study on excessive shoot development in bamboo, which will facilitate hypothesis building for future studies.

Gene expression data features high dimensionality, multicollinearity, and non-Gaussian distribution noise, posing hurdles for identification of true regulatory genes controlling a biological process or pathway. In this study, we integrated the Huber loss function and the Berhu penalty (HB) into partial least squares (PLS) framework to deal with the high dimension and multicollinearity property of gene expression data, and developed a new method called HB-PLS regression to model the relationships between regulatory genes and pathway genes. To solve the Huber-Berhu optimization problem, an accelerated proximal gradient descent algorithm with at least 10 times faster than the general convex optimization solver (CVX), was developed. Application of HB-PLS to recognize pathway regulators of lignin biosynthesis and photosynthesis in Arabidopsis thaliana led to the identification of many known positive pathway regulators that had previously been experimentally validated. As compared to sparse partial least squares (SPLS) regression, an efficient method for variable selection and dimension reduction in handling multicollinearity, HB-PLS has higher efficacy in identifying more positive known regulators, a much higher but slightly less sensitivity/(1-specificity) in ranking the true positive known regulators to the top of the output regulatory gene lists for the two aforementioned pathways. In addition, each method could identify some unique regulators that cannot be identified by the other methods. Our results showed that the overall performance of HB-PLS slightly exceeds that of SPLS but both methods are instrumental for identifying real pathway regulators from high-throughput gene expression data, suggesting that integration of statistics, machine leaning and convex optimization can result in a method with high efficacy and is worth further exploration.