PDF(Pubmed)
Abstract：
Despite global warming, the influence of heat on symbiotic nodules is scarcely studied. In this study, the effects of heat stress on the functioning of nodules formed by Rhizobium leguminosarum bv. viciae strain 3841 on pea (Pisum sativum) line SGE were analyzed. The influence of elevated temperature was analyzed at histological, ultrastructural, and transcriptional levels. As a result, an unusual apical pattern of nodule senescence was revealed. After five days of exposure, a senescence zone with degraded symbiotic structures was formed in place of the distal nitrogen fixation zone. There was downregulation of various genes, including those associated with the assimilation of fixed nitrogen and leghemoglobin. After nine days, the complete destruction of the nodules was demonstrated. It was shown that nodule recovery was possible after exposure to elevated temperature for 3 days but not after 5 days (which coincides with heat wave duration). At the same time, the exposure of plants to optimal temperature during the night leveled the negative effects. Thus, the study of the effects of elevated temperature on symbiotic nodules using a well-studied pea genotype and Rhizobium strain led to the discovery of a novel positional response of the nodule to heat stress.
摘要：
尽管全球变暖,很少研究热量对共生结节的影响。在这项研究中,热应激对豆科根瘤菌形成的结节功能的影响。分析了豌豆（Pisumsativum）系SGE上的viicae菌株3841。在组织学上分析了升高温度的影响，超微结构，和转录水平。因此,揭示了结节衰老的异常顶端模式。暴露五天后，形成了具有降解的共生结构的衰老区，代替了远端固氮区。各种基因下调，包括与固定氮和豆血红蛋白同化有关的那些。九天后,表明结核完全被破坏。结果表明，在高温下暴露3天后，结节恢复是可能的，但在5天后则不是（与热浪持续时间一致）。同时,植物在夜间暴露于最佳温度水平的负面影响。因此，使用经过充分研究的豌豆基因型和根瘤菌菌株对高温对共生结节的影响的研究导致发现了结节对热胁迫的新型位置响应。
