Identification of lumichrome as a Sinorhizobium enhancer of alfalfa root respiration and shoot growth
Identification of lumichrome as a Sinorhizobium enhancer of alfalfa root respiration and shoot growth
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DOI：
10.1073/pnas.96.22.12275
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发表时间：
1999-10-26
影响因子：
11.1
通讯作者：
Volpin, H
中科院分区：
文献类型：
--
作者：
Phillips, DA;Joseph, CM;Volpin, H
苜蓿中华根瘤菌（Sinorhizobium meliloti）细菌产生增强苜蓿（Medicago sativa L.）还引发了全植物净碳同化的补偿性增加。核磁共振、质谱和紫外-可见吸收鉴定这种增强剂为光色素，一种常见的核黄素分解产物。3 nM光色素处理苜蓿根系48 h后，根系呼吸增加21%（P < 0.05）。一个密切相关的增加净碳同化的地上部补偿增强根呼吸。例如，在12天后，将5 nM光色素施用到苜蓿幼根上使植物生长增加8%（P < 0.05）。在萌发前将苜蓿种子浸泡在5 nM的光色素中，在同一时期内生长增加了18%（P < 0.01）。两种情况都是。显著的生长促进作用（P < 0.05）仅在地上部中是明显的。5.苜蓿的生长需要外源CO（2），并可能直接受益于光色素引发的根系呼吸增强。因此中华根瘤菌-苜蓿联合体。最终形成共生：减少N（2）的根瘤，可能有利于在早期发育阶段的光色素，以前未认识到的互惠信号。在许多生理条件下核黄素迅速降解为光色素，根际细菌释放核黄素的普遍性表明，在5。苜蓿-紫花苜蓿结合可能在许多植物-微生物相互作用中具有广泛的重要性。
Sinorhizobium meliloti bacteria produce a signal molecule that enhances root respiration in alfalfa (Medicago sativa L.) and also triggers a compensatory increase in whole-plant net carbon assimilation. Nuclear magnetic resonance, mass spectrometry, and ultraviolet-visible absorption identify the enhancer as lumichrome, a common breakdown product of riboflavin. Treating alfalfa roots with 3 nM lumichrome increased root respiration 21% (P < 0.05) within 48 h. A closely linked increase in net carbon assimilation by the shoot compensated for the enhanced root respiration. For example, applying 5 nM lumichrome to young alfalfa roots increased plant growth by 8% (P < 0.05) after 12 days. Soaking alfalfa seeds in 5 nM lumichrome before germination increased growth by 18% (P < 0.01) over the same period. In both cases. significant growth enhancement (P < 0.05) was evident only in the shoot. 5. meliloti requires exogenous CO(2) for growth and may benefit directly from the enhanced root respiration that is triggered by lumichrome. Thus Sinorhizobium-alfalfa associations. which ultimately form symbiotic: N(2)-reducing root nodules, may be favored at an early developmental stage by lumichrome, a previously unrecognized mutualistic signal. The rapid degradation of riboflavin to lumichrome under many physiological conditions and the prevalence of riboflavin release by rhizosphere bacteria suggest that events demonstrated here in the 5. meliloti-alfalfa association may be widely important across many plant-microbe interactions.