Microbial Volatile Emissions Promote Accumulation of Exceptionally High Levels of Starch in Leaves in Mono- and Dicotyledonous Plants
Microbial Volatile Emissions Promote Accumulation of Exceptionally High Levels of Starch in Leaves in Mono- and Dicotyledonous Plants
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DOI：
10.1093/pcp/pcq126
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发表时间：
2010-10-01
影响因子：
4.9
通讯作者：
Pozueta-Romero, Javier
中科院分区：
文献类型：
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作者：
Ezquer, Ignacio;Li, Jun;Pozueta-Romero, Javier
微生物释放挥发性化合物，影响植物的生长和发育。然而，关于微生物排放如何影响植物中的初级碳水化合物代谢，人们知之甚少或一无所知。在这项工作中，我们探讨了从革兰氏阴性和革兰氏阳性细菌到真菌的不同微生物物种释放的挥发物对叶片淀粉代谢的影响。令人惊讶的是，我们发现所有测试的微生物物种（包括植物病原体和通常不与植物相互作用的物种）都释放出强烈促进单子叶和双子叶植物叶片中淀粉积累的挥发物。用微生物挥发物处理2d的植株叶片中淀粉含量与马铃薯块茎等储备器官相当甚至更高。转录组和酶活性分析暴露于互隔交链孢菌挥发物的马铃薯叶片显示，淀粉过度积累伴随着蔗糖合成酶，转化酶抑制剂，淀粉合成酶III和IV类，淀粉分支酶和葡萄糖-6-磷酸转运蛋白的上调。这种现象，指定为MIVOISAP（微生物挥发物诱导的淀粉积累过程），也伴随着下调酸性转化酶，质体硫氧还蛋白，淀粉分解酶，蛋白质参与内部氨基酸供应和不太明确的机制，涉及细菌型严格的反应。用真菌挥发物处理马铃薯叶也导致蔗糖、ADP葡萄糖、UDP葡萄糖和3-磷酸甘油酸的水平提高。MIVOISAP不依赖于培养基中蔗糖的存在，并且被半胱氨酸补充强烈抑制。微生物挥发物引起植物叶片淀粉积累增强的发现，为微生物诱导植物碳水化合物代谢提供了一个未报道的机制。
Microbes emit volatile compounds that affect plant growth and development. However, little or nothing is known about how microbial emissions may affect primary carbohydrate metabolism in plants. In this work we explored the effect on leaf starch metabolism of volatiles released from different microbial species ranging from Gram-negative and Gram-positive bacteria to fungi. Surprisingly, we found that all microbial species tested (including plant pathogens and species not normally interacting with plants) emitted volatiles that strongly promoted starch accumulation in leaves of both mono-and dicotyledonous plants. Starch content in leaves of plants treated for 2d with microbial volatiles was comparable with or even higher than that of reserve organs such as potato tubers. Transcriptome and enzyme activity analyses of potato leaves exposed to volatiles emitted by Alternaria alternata revealed that starch overaccumulation was accompanied by up-regulation of sucrose synthase, invertase inhibitors, starch synthase class III and IV, starch branching enzyme and glucose-6-phosphate transporter. This phenomenon, designated as MIVOISAP (microbial volatiles-induced starch accumulation process), was also accompanied by down-regulation of acid invertase, plastidial thioredoxins, starch breakdown enzymes, proteins involved in internal amino acid provision and less well defined mechanisms involving a bacterial-type stringent response. Treatment of potato leaves with fungal volatiles also resulted in enhanced levels of sucrose, ADPglucose, UDPglucose and 3-phosphoglycerate. MIVOISAP is independent of the presence of sucrose in the culture medium and is strongly repressed by cysteine supplementation. The discovery that microbial volatiles trigger starch accumulation enhancement in leaves constitutes an unreported mechanism for the elicidation of plant carbohydrate metabolism by microbes.