Appropriate timing of flowering is pivotal for tobacco, while chilling stress occurring at the seedling stage often undesirably leads to early flowering. However, the potential mechanism underlying chilling-induced early flowering remains unknown. Here, transcriptome sequencing was performed in tobacco with or without chilling at both seedling and budding stages. Chilling affected the expression of numerous genes at the seedling stage, while these dramatic expression changes were largely eliminated at the budding stage. A small number of genes related to metabolism, flower development, and stress tolerance continued to keep their altered expression patterns from the seedling stage to the budding stage. Many potential flowering-related genes involved in flowering pathways were identified and over half of them were differentially expressed. Functional analysis revealed that the down-regulation of NbXTH22 rendered tobacco less sensitive to chilling-induced early flowering. These results provide valuable resources for the investigation of flowering regulatory mechanisms and contribute to the genetic improvement of crops.
MicroRNAs (miRNAs) are small, endogenously expressed, nonprotein-coding RNAs that regulate gene expression at the post-transcriptional level in both animals and plants through repressing translation or inducing mRNA degradation. A comprehensive strategy to identify new miRNA homologs by mining the repository of available strawberry expressed sequence tags (ESTs) was developed. By adopting a range of filtering criteria, we identified 11 potential miRNAs belonging to 5 miRNA families from 47 890 Fragaria vesca EST sequences. Using 2 specific 5′ and 3′ miRNA RACE PCR reactions and a sequence-directed cloning method, we accurately determined both end sequences of 5 candidate miRNAs. Meanwhile, qRT-PCR was used to detect the expression of these 5 miRNAs in different strawberry organs and tissues at several growing stages. These newly identified F. vesca miRNAs (fve-miRNAs) and their expression information can improve our understanding of possible roles of fve-miRNAs in regulating the growth and development of F. vesca.
Abstract Background MicroRNAs (miRNAs), involving in various biological and metabolic processes, have been discovered and analyzed in quite a number of plants species, such as Arabidopsis , rice and other plants. However, there have been few reports about grapevine miRNAs in response to gibberelline (GA 3 ). Results Solexa technology was used to sequence small RNA libraries constructed from grapevine berries treated with GA 3 and the control. A total of 122 known and 90 novel grapevine miRNAs (Vvi-miRNAs) were identified. Totally, 137 ones were found to be clearly responsive to GA 3 , among which 58 were down-regulated, 51 were up-regulated, 21 could only be detected in the control, and seven were only detected in the treatment. Subsequently, we found that 28 of them were differentially regulated by GA 3 , with 12 conserved and 16 novel Vvi-miRNAs, based on the analysis of qRT-PCR essays. There existed some consistency in expression levels of GA 3 -responsive Vvi-miRNAs between high throughput sequencing and qRT-PCR essays. In addition, 117 target genes for 29 novel miRNAs were predicted. Conclusions Deep sequencing of short RNAs from grapevine berries treated with GA3 and the control identified 137 GA 3 -responsive miRNAs, among which 28 exhibited different expression profiles of response to GA 3 in the diverse developmental stages of grapevine berries. These identified Vvi-miRNAs might be involved in the grapevine berry development and response to environmental stresses.
Objective: To study the correlation betwee n morphological variation and gentiopicroside content in cultivated Gentian a manshurica roots and to investigate the feasibility of breeding new varietie s of high effective constituent content. Method: Gen tiopicroside was determined in 5 morphological types of cultivated G. manshuri ca roots by HPLC, which are normal (or wild) type, white-flowered type, thi ck-rooted type, broad-leaved type I and broad-leaved type Ⅱ. Res ult: Among different types gentiopicroside content is the highest in the roots of thick-rooted type, the contents decrease as following order: norm al type, broad-leaved type I white-flowe red type and broad-leaved type II, and the gentiopicros ide contents in the same type root system are a positive correlation with root a ges, as 3-years-age roots2-years-age roots1-year-age varied with roots . Conclusion: The contents of effective constituent vary with the morphological variation in cultivated G. manshurica. It is feasib le to breed a new variety with high effective constituent with the morphol ogical character as a selecting index.[
Porcine circovirus type 3 (PCV-3) had posed a potential threat to the swine industry since its discovery in the United States in 2015. The Shanxi province had a wide range of large-scale pig farms in China, but the transmission of PCV-3 was unclear. To further investigate the epidemic profile and genetic diversity of the virus, the lung samples (491) from 19 different pig slaughterhouse in 11 cities covering the whole of the Shanxi province of China were evaluated by PCR. The results indicated that the PCV-3 positive rate at the slaughterhouse level and at the individual level was 100% (19/19) and 86.76% (426/491), respectively. The PCR-positive samples were further sequenced, and eight new PCV3 isolates were identified. The complete genomes of the eight virus isolates showed 97.45%–99.90% nucleotide identity with other PCV-3 isolates available in NCBI. Phylogenetic analysis based on the complete genome and capsid gene divided the PCV-3 strains into two main groups and several subclusters. The eight identified PCV-3 strains could be divided into the same clades, according to amino acid mutations A24/V and R27/K of Cap proteins. The results could provide new insight into the prevalence and genetic variation of PCV-3 in the Shanxi province of China, as well as the possibility of transmission from this center. It also reminded me that the molecular epidemiology of this new circovirus was urgent.
Abstract The combination of Chinsurah Boro II (BT)-type cytoplasmic male sterility (CMS) and Rf1 , the main fertility restorer gene ( Rf ) for CMS-BT, has been extensively utilized for the production of three-line commercial japonica hybrid seeds. The identification of new Rf genes holds significance for the breeding BT-type restorer lines, aiming to enhance the heterosis level of BT-type japonica hybrids. In this present study, ‘02428’, a wide-compatibility japonica variety, was observed to partially restore fertility to BT-type CMS lines. Genetic analysis revealed that ‘02428’ carries a dominant Rf gene, Rf21(t) , responsible for the fertility restoration of BT-type CMS lines. Leveraging BSA resequencing technology and molecular markers, the Rf21(t) locus was identified, and localized within a candidate interval of 6-12.5Mb on chromosome 2. Using the iso-cytoplasmic restorer populations, Rf21(t) was ultimately mapped to an interval of approximately 77 kb, encompassing 12 predicted genes, including LOC_Os02g17360 , encoding a PPR domain-containing protein and LOC_Os02g17380 (Rf2) , a cloned Rf for Lead rice-type CMS. Comparative sequence analysis, gene expression profiling, and gene knockout experiments confirmed LOC_Os02g17360 and LOC_Os02g17380 as the most likely candidates of Rf21(t) . Furthermore, Rf21(t) showed the dosage effect on the fertility restoration of BT-type CMS lines. This newly identified Rf21(t) represents a valuable genetic resource for the breeding of BT-type japonica restorer lines. Our findings offer practical insights for breeders interested in advancing BT-type japonica hybrid development.
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