Integrating transcriptomics and metabolomics to characterise the response of Astragalus membranaceus Bge. var. mongolicus (Bge.) to progressive drought stress.

BACKGROUND: Astragalus membranaceus Bge. var. mongolicus (Bge.) Hsiao (A. mongolicus) is an important traditional Chinese herb that is cultivated on a large scale in northwestern China. Understanding plant responses to drought has important effects on ecological environment recovery and local economic development. Here, we combined transcriptomics (Illumina Hiseq 2000) and metabolomics ((1)H-NMR) to investigate how the roots of two-year-old A. mongolicus responded to 14 days of progressive drought stress. RESULTS: The dried soil reduced the relative water content (RWC) of the leaves and biomass, induced the differential expression of a large fraction of the transcriptome and significantly altered the metabolic processes. PCA analysis demonstrated that the sucrose, proline, and malate metabolites contributed greatly to the separation. Strikingly, proline was increased by almost 60-fold under severe stress compared to the control. Some backbone pathways, including glycolysis, tricarboxylic acid (TCA) cycle, glutamate-mediated proline biosynthesis, aspartate family metabolism and starch and sucrose metabolism, were significantly affected by drought. An integrated analysis of the interaction between key genes and the altered metabolites involved in these pathways was performed. CONCLUSIONS: Our findings demonstrated that the expression of drought-responsive genes showed a strong stress-dose dependency. Analysis of backbone pathways of the transcriptome and metabolome revealed specific genotypic responses to different levels of drought. The variation in molecular strategies to the drought may play an important role in how A. mongolicus and other legume crops adapt to drought stress.

Necroptosis Mediates Cigarette Smoke-Induced Inflammatory Responses in Macrophages.

Introduction: Cigarette smoke (CS)-induced inflammation in macrophages is involved in the pathological process of chronic obstructive pulmonary disease (COPD). Necroptosis, which is a form of programmed necrosis, has a close relationship with robust inflammation, while its roles in COPD are unclear. Materials and Methods: Necroptosis markers were measured in mouse alveolar macrophages and cultured bone marrow-derived macrophages (BMDMs). Necroptosis inhibitors were used to block necroptosis in BMDMs, and inflammatory cytokines were detected. We further explored the related signaling pathways. Results: In this study, we demonstrated the way in which necroptosis, in addition to its upstream and downstream signals, regulates CS-induced inflammatory responses in macrophages. We observed that CS exposure caused a significant increase in the levels of necroptosis markers (receptor interacting kinases [RIPK] 1 and 3) in mouse alveolar macrophages and BMDMs. Pharmacological inhibition of RIPK1 or 3 caused a significant suppression in CS extract (CSE)-induced inflammatory cytokines, chemokine ligands (CXCL) 1 and 2, and interleukin (IL)-6 in BMDMs. CSE-induced necroptosis was regulated by mitochondrial reactive oxygen species (mitoROS), which also promoted inflammation in BMDMs. Furthermore, necroptosis regulated CSE-induced inflammatory responses in BMDMs, most likely through activation of the nuclear factor-κB pathway. Conclusion: Taken together, our results demonstrate that mitoROS-dependent necroptosis is essential for CS-induced inflammation in BMDMs and suggest that inhibition of necroptosis in macrophages may represent effective therapeutic approaches for COPD patients.

[Effects of NaCl stress on cation contents in different pumpkin cultivars' seedlings].

With the seedlings of 19 pumpkin cultivars as test materials, this paper studied the variations of Na+, K+, Ca2+, Na+/K+, Na+/Ca2+, SN+, K+ and SNa+, ca2+ in their shoots and roots under the stress of 300 mmol NaCl x L(-1). The results showed that after an 8-day exposure to 300 mmol NaCl x L(-1), the Na+ content in the seedlings increased significantly while the K+ content decreased, resulting in the brokenness of ion balance. The root Na+ content, shoot Na+/K+ and Na+/Ca2+ ratios, and SNa+, K+ and SNa+, Ca2+ of Cucurbita moschata (Q1) were significantly higher than those of C. maxima (H2) and C. ficifolia (H3). The variation tendency of these parameters of different pumpkin cultivars' seedlings were nearly consistent with the salt injury index of the seedlings under NaCl stress, which further proved that the strong salt-tolerance of Q1 was related to the lower values of shoot Na+/K+, Na+/Ca2+, SNa+, K+ and SNa+, Ca2+, and the high contents of K+ and Ca2+, while the salt-sensitivity of H2 and H3 was related to the higher values of shoot Na+/K+, Na+/Ca2+, SNa+, K+ and SNa+, Ca2+, and low contents of K+ and Ca2+ under NaCl stress.