在表现出休眠或逃避策略以耐受水淹的水稻基因型的叶鞘中，通气组织形成的不同机制。
Distinct mechanisms for aerenchyma formation in leaf sheaths of rice genotypes displaying a quiescence or escape strategy for flooding tolerance.
机构信息
PlantLab, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà 33, Pisa, Italy.
出版信息
Ann Bot. 2011 Jun;107(8):1335-43. doi: 10.1093/aob/mcr086. Epub 2011 Apr 12.
BACKGROUND AND AIMS
Rice is one of the few crops able to withstand periods of partial or even complete submergence. One of the adaptive traits of rice is the constitutive presence and further development of aerenchyma which enables oxygen to be transported to submerged organs. The development of lysigenous aerenchyma is promoted by ethylene accumulating within the submerged plant tissues, although other signalling mechanisms may also co-exist. In this study, aerenchyma development was analysed in two rice (Oryza sativa) varieties, 'FR13A' and 'Arborio Precoce', which show opposite traits in flooding response in terms of internode elongation and survival.
METHODS
The growth and survival of rice varieties under submergence was investigated in the leaf sheath of 'FR13A' and 'Arborio Precoce'. The possible involvement of ethylene and reactive oxygen species (ROS) was evaluated in relation to aerenchyma formation. Cell viability and DNA fragmentation were determined by FDA/FM4-64 staining and TUNEL assay, respectively. Ethylene production was monitored by gas chromatography and by analysing ACO gene expression. ROS production was measured by using Amplex Red assay kit and the fluorescent dye DCFH(2)-DA. The expression of APX1 was also evaluated. AVG and DPI solutions were used to test the effect of inhibiting ethylene biosynthesis and ROS production, respectively.
KEY RESULTS
Both the varieties displayed constitutive lysigenous aerenchyma formation, which was further enhanced when submerged. 'Arborio Precoce', which is characterized by fast elongation when submerged, showed active ethylene biosynthetic machinery associated with increased aerenchymatous areas. 'FR13A', which harbours the Sub1A gene that limits growth during oxygen deprivation, did not show any increase in ethylene production after submersion but still displayed increased aerenchyma. Hydrogen peroxide levels increased in 'FR13A' but not in 'Arborio Precoce'.
CONCLUSIONS
While ethylene controls aerenchyma formation in the fast-elongating 'Arborio Precoce' variety, in 'FR13A' ROS accumulation plays an important role.
背景与目的
水稻是少数几种能够耐受部分甚至完全淹没的作物之一。水稻的一种适应特性是组成性存在并进一步发育气腔组织，从而使氧气能够输送到淹没的器官。尽管可能存在其他信号机制，但乙烯在植物组织中的积累促进了溶生性气腔组织的发育。在这项研究中，分析了两种水稻（Oryza sativa）品种“FR13A”和“Arborio Precoce”中气腔组织的发育情况，这两个品种在节间伸长和存活方面对水淹反应表现出相反的特性。
方法
研究了“FR13A”和“Arborio Precoce”叶片鞘中的水稻品种在淹没条件下的生长和存活情况。评估了乙烯和活性氧（ROS）的可能参与与气腔形成的关系。通过 FDA/FM4-64 染色和 TUNEL 测定分别确定细胞活力和 DNA 片段化。通过气相色谱法和分析 ACO 基因表达监测乙烯的产生。通过使用 Amplex Red 测定试剂盒和荧光染料 DCFH(2)-DA 测量 ROS 的产生。还评估了 APX1 的表达。使用 AVG 和 DPI 溶液分别测试抑制乙烯生物合成和 ROS 产生的效果。
主要结果
两个品种都表现出组成性溶生性气腔组织的形成，当淹没时进一步增强。“Arborio Precoce”在淹没时表现出快速伸长的特性，其具有与增加的气腔区域相关的活跃的乙烯生物合成机制。而“FR13A”则含有限制缺氧生长的 Sub1A 基因，淹没后没有增加乙烯的产生，但仍显示出增加的气腔。“FR13A”中的过氧化氢水平增加，但“Arborio Precoce”中没有增加。
结论
虽然乙烯控制着快速伸长的“Arborio Precoce”品种中气腔组织的形成，但在“FR13A”中，ROS 的积累起着重要的作用。
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