Seed germination requires the relaxation of endosperm cap and radicle cell walls, with cell wall hydrolases playing a significant role in this process. Our study revealed that a type of cell wall hydrolase, xyloglucan endotransglucosylase, may significantly contribute to endosperm weakening during lettuce seed germination. Through bioinformatics analysis, the XTH gene family in lettuce was divided into five subfamilies localized on nine chromosomes. Notably, there were significant differences in gene structure among the members of the LsXTHs family containing 1–4 exons and 20 conserved motifs. Among these motifs, motif1, motif2, and motif3 encoded the XTH structural domain. The promoter regions of LsXTHs contained a large number of cis-acting elements responsive to various abiotic stresses, such as drought, anaerobiosis, low temperature, high temperature, and salt stress. Germination experiments showed that seeds imbibed in water and 5 μmol/L abscisic acid (ABA) were able to achieve typical germination with radicle protrusion from the endosperm cap, achieving germination of 100% and 36%, respectively. Conversely, in 0.3% sodium dichloroisocyanurate (SDIC), the swollen seeds were unable to germinate or complete atypical germination, resulting in a germination rate of 30%. Compared to the control, the mechanical strength of the endosperm cap of seeds imbibed in 0.3% SDIC for 8 h increased by 14%, indicating that SDIC may inhibit seed germination by enhancing the mechanical strength of the endosperm cap. Enzyme activity analysis revealed that during lettuce seed germination, XTH enzyme activity in the endosperm cap was significantly higher than in other tissues and increased gradually with imbibition. Transcriptome analysis of the endosperm cap detected the expression of 10 LsXTH genes. Among these, LsXTH43 exhibited the highest expression during germination and was significantly upregulated two-fold by high temperatures, suggesting a potential role in the high-temperature germination of lettuce seeds. Additionally, SDIC downregulated the expression of LsXTHs to varying degrees, with the expression of LsXTH15 reduced to only 6% of its original level. Low temperature, high temperature, drought, and salt stress all reduced the expression of most LsXTHs to different degrees; when seeds germinated under waterlogging and cadmium stress, LsXTH6, LsXTH7, LsXTH8, LsXTH32, and LsXTH33 were all upregulated to some extent.

Tuberculosis (TB) is an infectious disease, caused by Mycobacterium tuberculosis, primarily affecting the lungs. The M. tuberculosis strain of the Haarlem family named M was responsible for a large multidrug‐resistant TB (MDR‐TB) outbreak in Buenos Aires. This outbreak started in the early 1990s and in the mid 2000s still accounted for 29% of all MDR‐TB cases in Argentina. By contrast, a clonal variant of strain M, named 410, has caused a single tuberculosis case since the onset of the outbreak. The molecular bases of the high epidemiological fitness of the M strain remain unclear. To assess its unique molecular properties, herein, we performed a comparative protein and lipid analysis of a representative clone of the M strain (Mp) and the nonprosperous M variant 410. We also evaluated their growth in low pH. The variant 410 had higher levels of latency proteins under standard conditions and delayed growth at low pH, suggesting that it is more sensitive to stress stimuli than Mp. Moreover, Mp showed higher levels of mycolic acids covalently attached to the cell wall and lower accumulation of free mycolic acids in the outer layer than the 410 strain. The low expression of latency proteins together with the reduced content of surface mycolic acids may facilitate Mp to evade the host immune responses.

Pogostemon cablin (patchouli) is a well-known perennial herbaceous plant for traditional Chinese medicine, and its primary bioactive compounds are patchoulol and pogostone. The biosynthesis pathway of patchouli has been well resolved early, while the biosynthesis pathway of pogostone is still not fully resolved due to the lack of terminal enzyme directly synthesizing pogostone. Here, the present study aims to predict the terminal enzyme of pogostone biosynthesis and reconstruct its most possible complete biosynthesis, through the integrated transcriptomic and metabolomic analysis. The metabolomic and transcriptomic profiles of patchouli leaf were largely different to those of root and stem. Patchoulol analogs like patchoulene and germacrene mainly accumulated in leaf, while pogostone content was much higher in root. Based on the integrated analysis of differentially expressed genes and metabolites, we reconstructed the biosynthesis pathways of patchoulol, and predicted the most likely complete biosynthesis pathway of pogostone. Besides, we identified 29 highly-expressed genes involved in pogostone biosynthesis for the neo-octoploid genome of patchouli, and most of their expression levels were strongly correlated with pogostone content. In particular, patchouli BAHD-DCR acyltransferases (BAHD-DCRs) were phylogenetically distant from but structurally similar to the other known plant BAHD acyltransferases. Most of them possessed the conservative catalysis motif HXXXD, and the catalysis center could bind to the widely recognized substrate molecules of 4-hydroxy-6-methyl-2-pyrone and 4-methylvaleryl-CoA and product molecule of pogostone. Thus, the highly-expressed BAHD-DCRs in patchouli root were proposed to be terminal enzymes directly synthesizing pogostone. The findings here provide more supporting evidence for the medical use of patchouli whole plants, and make an important step forward fully resolving the pogostone biosynthesis pathway. The identified genes involved in pogostone biosynthesis, especially BAHD-DCRs, deserve further investigation and utilization in the synthetic production of pogostone.

EHEC O157:H7 is responsible for Hemolytic Uremic Syndrome (HUS) outbreaks in humans and its virulence is associated with Shiga toxin (Stx). During the pathogenesis of HUS, EHEC O157:H7 is phagocytized by the intestinal host macrophage into the phagosome. According to our study, a low percentage of phagocytized bacteria survived in the murine macrophage phagosome. To understand the initials mechanisms involved in bacterial persistence, we performed a global profile of bacterial RNAseq analysis in the early phagosome of murine macrophage and in vitro assays with more extreme stress conditions. The defense strategy of an early murine phagosome consisted on producing DNA damage, membrane damage, acid pH and nitric oxide (NO) agents. These hostile conditions triggering the bacterial SOS response, lipid biosynthesis and NO detoxification enzymes in response to DNA damage, membrane damage and nitric oxide agents, respectively. In turn, to survive, the bacterium conserves energy by downregulating flagellar biosynthesis, T3SS and T6SS virulence mechanisms. In contrast, stx2a expression is upregulated. At the same time, it increases the ribosomal levels and amino acid synthesis to react more effectively against adverse conditions. Under more extreme stress conditions, EHEC O157:H7 expressed genes related to an acidic environment (pH 4.5) upregulating the acid stress response pathways AR2-5, whereas, upon high concentrations of hydrogen peroxide, it transcribed higher levels of genes of the OxyR pathway and subsequently hydrogen peroxide oxidative stress-related genes.

In 2014, A novel tick-borne virus of the genus Flavivirus was first reported from the Mogiana region in Brazil. This virus was named the Mogiana tick virus (MGTV). Later, MGTV was also named as Jingmen tick virus (JMTV), Kindia tick virus (KDTV), Guangxi tick virus (GXTV) etc. In the present study, we used small RNA sequencing (sRNA-seq) to detect viruses in ticks and detected MGTV in Amblyomma testudinarium ticks, which had been captured in Yunnan province of China in the year of 2016. The full-length genome sequence of a new MGTV strain Yunnan2016 (GenBank: MT080097 , MT080098 , MT080099 and MT080100 ) was obtained and recommended to be included into the NCBI RefSeq database for the future studies of MGTV. Our phylogenetic analyses showed that viruses named MGTV, JMTV, KDTV and GXTV are monophyletic: the MGTV group (lineage) of viruses. We show, for the first time, that 5′ and 3′ sRNAs can be used to obtain full-length sequences of the 5’ and 3’ ends of, but not limited to genome sequences of RNA viruses. And we proved the feasibility of using the sRNA-seq based method for the detection of viruses in a sample containing miniscule RNA.