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Ruibo Hu Junling Li Xuanwen Yang Xun Zhao Xiaoyu Wang Qi Tang Guo He Gongke Zhou Yingzhen Kong 《Plant molecular biology》2016,92(1-2):25-38
Large quantities of mucilage are synthesized in seed coat epidermis cells during seed coat differentiation. This process is an ideal model system for the study of plant cell wall biosynthesis and modifications. In this study, we show that mutation in Irregular Xylem 7 (IRX7) results in a defect in mucilage adherence due to reduced xylan biosynthesis. IRX7 was expressed in the seeds from 4 days post-anthesis (DPA) to 13 DPA, with the peak of expression at 13 DPA. The seed coat epidermis cells of irx7 displayed no aberrant morphology during differentiation, and these cells synthesized and deposited the same amount of mucilage as did wild type (WT) cells. However, the distribution of the water-soluble vs. adherent mucilage layers was significantly altered in irx7 compared to the WT. Both the amount of xylose and the extent of glycosyl linkages of xylan was dramatically decreased in irx7 water-soluble and adherent mucilage compared to the WT. The polymeric structure of water-soluble mucilage was altered in irx7, with a total loss of the higher molecular weight polymer components present in the WT. Correspondingly, whole-seed immunolabeling assays and dot-immunoassays of extracted mucilage indicated dramatic changes in rhamnogalacturonan I (RG I) and xylan epitopes in irx7 mucilage. Furthermore, the crystalline cellulose content was significantly reduced in irx7 mucilage. Taken together, these results indicate that xylan synthesized by IRX7 plays an essential role in maintaining the adhesive property of seed coat mucilage, and its structural role is potentially implemented through its interaction with cellulose. 相似文献
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Reconstructing changes in the genotype,phenotype, and climatic niche of an introduced species 下载免费PDF全文
Daniel Z. Atwater U. Uzay Sezen Valorie Goff Wenqian Kong Andrew H. Paterson Jacob N. Barney 《Ecography》2016,39(9):894-903
An introduced species must contend with enormous environmental variation in its introduced range. In this study, we use niche models and ordination analyses to reconstruct changes in genotype, phenotype, and climatic niche of Johnsongrass Sorghum halepense, which is regarded as one of the world's most threatening invasive plants. In the United States, Johnsongrass has rapidly evolved within‐ and among‐population genetic diversity; our results show that genetic differentiation in expanding Johnsongrass populations has resulted in phenotypic variation that is consistent with habitat and climatic variation encountered during its expansion. Moreover, Johnsongrass expanded from agricultural to non‐agricultural habitat, and now, despite occupying overlapping ranges, extant agricultural and non‐agricultural populations are genetically and phenotypically distinct and manifest different plastic responses when encountering environmental variation. Non‐agricultural accessions are broadly distributed in climatic and geographic space and their fitness traits demonstrate plastic responses to common garden conditions that are consistent with local specialization. In contrast, agricultural accessions demonstrate ‘general purpose’ plastic responses and have more restricted climatic niches and geographic distributions. They also grow much larger than non‐agricultural accessions. If these differences are adaptive, our results suggest that adaptation to local habitat variation plays a crucial role in the ecology of this invader. Further, its success relates to its ability to succeed on dual fronts, by responding simultaneously to habitat and climate variability and by capitalizing on differential responses to these factors during its range expansion. 相似文献
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通过对秦岭山区中国大鲵(Andrias davidianus)栖息地生境因子调查、统计,利用R语言分析了各因子与大鲵生境选择的相关性,得出研究结果:秦岭山区影响大鲵生存的主要因子为栖息地类型(相关系数r=0.98),其次是水温(相关系数r=-0.8)、河岸坡度(r=-0.6)和p H (r=-0.6);浊度(相关系数r=0.5)、电导率(r=0.49)、DO(r=0.4)、人为干扰(r=0.35)和海拔(r=0.31)对大鲵分布影响不大。研究结果为探讨中国大鲵对野生环境的适应性选择提供了参考。 相似文献
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Lin Chen Lingjun Kong Xinbing Wei Yimeng Wang Bing Wang Xiumei Zhang Jinpeng Sun Huiqing Liu 《Journal of cellular and molecular medicine》2019,23(5):3325-3335
We previously reported that nucleotide‐binding oligomerization domain‐containing protein (NOD) 2 was involved in the inflammatory responses to cerebral ischaemia/reperfusion (I/R) insult. However, the mechanism by which NOD2 participates in brain ischaemic injury and the regulation of NOD2 in the process are still obscure. Increased β‐arrestin 2 (ARRB2) expression was observed in microglia following cerebral I/R in wild‐type mice besides the up‐regulation of NOD2 and TRAF6. Stimulation of NOD2 by muramyl dipeptide (MDP) in BV2 cells induced the activation of NF‐κB by the phosphorylation of p65 subunit and the degradation of IκBα. Meanwhile, the protein level of Cyclooxygenase‐2 (COX‐2), the protein expression and activity of MMP‐9 were significantly increased in BV2 cells after administration of MDP. Furthermore, overexpression of ARRB2 significantly suppressed the inflammation induced by MDP, silence of ARRB2 significantly enhanced the inflammation induced by MDP in BV2 cells. In addition, we observed endogenous interaction of TRAF6 and ARRB2 after stimulation of MDP or cerebral I/R insult, indicating ARRB2 negatively regulates NOD2‐triggered inflammatory signalling pathway by associating with TRAF6 in microglia after cerebral I/R injury. Finally, the in vivo study clearly confirmed that ARRB2 negatively regulated NOD2‐induced inflammatory response, as ARRB2 deficiency exacerbated stroke outcomes and aggravated the NF‐κB signalling pathway induced by NOD2 stimulation after cerebral I/R injury. These findings revealed ARRB2 negatively regulated NOD2 signalling pathway through the association with TRAF6 in cerebral I/R injury. 相似文献