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In this paper, the phenomenon of phase transition is studied in an asymmetric tristable model driven by Lévy noise and Gaussian white noise. First, the fourth-order Runge-Kutta algorithm is used to simulate the stationary probability density of the system. Then we observe the shape of the stationary probability density curve by adjusting the system parameters and noise parameters. It has been found that asymmetric parameter, additive noise intensity, multiplicative noise intensity, the stability index, and the skewness parameter can all induce phase transition. Moreover, the influence of additive noise intensity and multiplicative noise intensity on the number and height of stationary probability density peaks is opposite. We also found that under the same asymmetric parameters, the influence of positive and negative skewness parameters on the stationary probability density is different.(讨论了非对称三稳系统在Lévy噪声和高斯白噪声共同驱动下的相转移问题。采用四阶Runge-Kutta算法，计算了系统的稳态概率密度函数，通过改变系统参数和噪声参数观察其稳态概率密度函数曲线形态的变化情况。研究发现，非对称参数、加性噪声强度、乘性噪声强度、稳定性指标、偏斜参数均可诱导系统相转移，当分别改变加性噪声强度和乘性噪声强度时，概率密度函数的峰数与高度的变化情况相反。此外，在相同的非对称参数下，随着偏斜参数正负取值的变化，概率密度曲线图中峰的结构亦呈现不同的现象。)

In this paper, we establish a stochastic dynamical grazing ecosystem with time delays and fluctuations. The effects of time delay, Gaussian noise and Lévy noise on the stationary probability distribution (SPD), the mean first passage time (MFPT) and stochastic resonance (SR) are analyzed. Our research results show the following: (i) For small time delay, the increasing Gaussian noise intensity leads to catastrophic regime shift (CRS) from high vegetation state to low vegetation state, while the increasing Lévy noise intensity contributes to the recovery of these shifts. For large time delay, the increasing Gaussian noise intensity or Lévy noise intensity causes the CRS phenomenon, the larger the time delay, the more frequent the CRS phenomenon. (ii) The increasing Gaussian noise intensity can diminish the stability of the high vegetation state and low vegetation state, the increasing Lévy noise intensity and Lévy stability index can enhance the stability of the high vegetation state and diminish the stability of the low vegetation state. The increasing Lévy noise intensity can lead to noise-enhanced stability (NES) of the high vegetation state, and the larger the time delay, the more pronounced the NES phenomenon. (iii) The increase of time delay can weaken SR phenomenon when signal-to-noise ratio (SNR) is a function of Gaussian noise intensity and Lévy noise intensity. [ABSTRACT FROM AUTHOR]

Plant senescence, as a highly integrated developmental stage, involves functional degeneration and nutrient redistribution. NAM/ATAF1/CUC (NAC) transcription factors orchestrate various senescence-related signals and mediate the fine-tuning underlying plant senescence. Previous data revealed that knockout of either NtNAC028 or NtNAC080 leads to delayed leaf senescence in tobacco (Nicotiana tabacum), which implies that NtNAC028 and NtNAC080 play respective roles in the regulation of leaf senescence, although they share 91.87% identity with each other. However, the mechanism underlying NtNAC028- and NtNAC080-regulated leaf senescence remains obscure. Here, we determined that NtNAC028 and NtNAC080 activate a putative jasmonic acid (JA) biosynthetic gene, NtLOX3 , and enhance the JA level in vivo. We found that NtNAC028 and NtNAC080 interact with each other and themselves through their NA-terminal region. Remarkably, only the dimerization between NtNAC028 and NtNAC080 stimulated the transcriptional activation activity, but not the DNA binding activity of this heterodimer on NtLOX3. Metabolome analysis indicated that overexpression of either NtNAC028 or NtNAC080 augments both biosynthesis and degradation of nicotine in the senescent stages. Thus, we conclude that NtNAC028 cooperates with NtNAC080 and forms a heterodimer to enhance NtLOX3 expression and JA biosynthesis to trigger the onset of leaf senescence and impact secondary metabolism in tobacco. [ABSTRACT FROM AUTHOR]

The domain of the unknown function (DUF) gene families assumes pivotal roles in plant metabolic and stress responses. However, our comprehension of the tobacco DUF668 (NtDUF668) gene family and its specific reactions to heavy metal, drought, and salt stresses remain circumscribed. In the current investigation, a comprehensive genome-wide analysis of the NtDUF668 gene family was undertaken utilizing bioinformatics tools. The results unveiled a total of 20 members in the NtDUF668 gene family, denominated NtDUF668-01 to NtDUF668-20. Phylogenetic analyses indicated a closer genetic relationship of DUF668 genes between Nicotiana tabacum and Ipomoea batatas. The examination of gene structure and conservative motifs revealed a bifurcation into two major Clades, aligning with previous studies on DUF668 gene families from various plant species, emphasizing its highly conserved evolutionary mechanism across plants. The exploration of promoter regions of NtDUF668 genes revealed a plethora of cis-acting elements associated with abiotic and biotic stresses, light signaling, and phytohormones. Gene duplication events and selection pressure analysis disclosed the segmental duplication and strong purifying selection pressure during the evolution of NtDUF668 genes. Syntenic analysis indicated a relatively conserved evolutionary mechanism of DUF668 gene families within dicotyledons. Tissue-specific expression analysis suggested that NtDUF668 family members are potentially involved in root development, floral organ formation, and abscission. The expression patterns and qRT–PCR analysis of NtDUF668 genes implied the potentially functional involvements of NtDUF668s in response to multiple abiotic stresses. Furthermore, the stress-triggered member NtDUF668-08 exhibited specific nuclear localization. In conclusion, this genome-wide analysis illuminates the composition, phylogenetic relationships, and potential roles of the NtDUF668 gene family in abiotic stress responses. The identified candidate genes, particularly NtDUF668-08, warrant further research for functional investigation. [ABSTRACT FROM AUTHOR]

Leaf morphology and plant height are two agronomic traits closely related to tobacco (Nicotiana tabacum L.) yield and quality. The study of leaf morphology and plant stature mutants will greatly contribute to the fields of plant architecture breeding and developmental biology. Here, we report the characterization of a spiral leaf and dwarf (sld) mutant identified from an ethylmethane sulfonate (EMS)-induced common tobacco population. The sld mutant displayed the phenotype of wrinkled, spiral, and miniature leaves, with the growth point as the central axis and plant dwarfing with shortened internodes. The inheritance pattern of the sld mutant phenotype was manipulated by a recessive nuclear monogene, which was linked to six tobacco simple sequence repeat (SSR) markers from linkage group 5 via gene mapping. Utilizing an F2 population, the sld mutant gene the sld mutant gene was located between the co-segregated markers PT51778, PT54913, and the marker PT61414, with an equal genetic distance of 0.16 cM. Taking advantage of a BC1F1 population, the markers PT51778, PT54913, the sld gene, and the marker PT61414 demonstrated co-segregation, located between the markers PT40040 and PT60933, respectively, with a genetic distance of 1.37 cM and 6.32 cM, respectively. These findings will be helpful in cloning the sld gene and in the further characterization of the regulatory genes controlling the spiral and dwarfing phenotypes in tobacco. [ABSTRACT FROM AUTHOR]