Maize Carbohydrate partitioning defective1 impacts carbohydrate distribution, callose accumulation, and phloem function.
Maize Carbohydrate partitioning defective1 impacts carbohydrate distribution, callose accumulation, and phloem function.
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DOI：
10.1093/jxb/ery203
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发表时间：
2018-07-18
影响因子：
6.9
通讯作者：
Braun DM
中科院分区：
文献类型：
--
作者：
Julius BT;Slewinski TL;Baker RF;Tzin V;Zhou S;Bihmidine S;Jander G;Braun DM
玉米碳水化合物分配缺陷1突变体导致筛元件中异位胼胝质形成，其部分抑制碳水化合物分配并与害虫暴露下的过度活跃的防御反应相关。植物在光合组织中合成碳水化合物，大多数植物将蔗糖运输到非光合组织以维持生长和发育。虽然调节蔗糖长距离运输的解剖学、生物化学和生理学过程已得到很好的表征，但关于控制全植物碳水化合物分配的基因却知之甚少。为了确定影响叶子碳输出的位点，我们筛选了诱变玉米植株，寻找与碳水化合物运输减少相关的表型，包括叶子中的缺绿症和过量的淀粉和可溶性糖。碳水化合物分配缺陷 1 (Cpd1) 被鉴定为表现出这些表型的半显性突变体。韧皮部运输实验表明，Cpd1/+突变体叶片中淀粉和可溶性糖的超积累是由于蔗糖输出受到抑制。有趣的是，在突变叶片的韧皮部中观察到异位胼胝质沉积物，这可能是运输减少的原因。除了碳水化合物超积累表型外，Cpd1/+ 突变体还过度积累苯并恶嗪类防御化合物，并在受到蚜虫攻击时表现出更高的耐受性。然而，Cpd1/+ 和不含苯并恶嗪类植物的双突变体研究表明，异位胼胝质和碳超积累与苯并恶嗪类化合物的产生无关。基于发育中韧皮部中胼胝质闭塞的形成，我们假设 cpd1 基因在韧皮部发育早期发挥作用，从而影响全植物碳水化合物的分配。
The maize Carbohydrate partitioning defective1 mutant causes ectopic callose formation in sieve elements, which partially inhibits carbohydrate partitioning and is associated with hyperactive defense responses under insect pest exposure. Plants synthesize carbohydrates in photosynthetic tissues, with the majority of plants transporting sucrose to non-photosynthetic tissues to sustain growth and development. While the anatomical, biochemical, and physiological processes regulating sucrose long-distance transport are well characterized, little is known concerning the genes controlling whole-plant carbohydrate partitioning. To identify loci influencing carbon export from leaves, we screened mutagenized maize plants for phenotypes associated with reduced carbohydrate transport, including chlorosis and excessive starch and soluble sugars in leaves. Carbohydrate partitioning defective1 (Cpd1) was identified as a semi-dominant mutant exhibiting these phenotypes. Phloem transport experiments suggested that the hyperaccumulation of starch and soluble sugars in the Cpd1/+ mutant leaves was due to inhibited sucrose export. Interestingly, ectopic callose deposits were observed in the phloem of mutant leaves, and probably underlie the decreased transport. In addition to the carbohydrate hyperaccumulation phenotype, Cpd1/+ mutants overaccumulate benzoxazinoid defense compounds and exhibit increased tolerance when attacked by aphids. However, double mutant studies between Cpd1/+ and benzoxazinoid-less plants indicate that the ectopic callose and carbon hyperaccumulation are independent of benzoxazinoid production. Based on the formation of callose occlusions in the developing phloem, we hypothesize that the cpd1 gene functions early in phloem development, thereby impacting whole-plant carbohydrate partitioning.
影响因子：
2.6
作者：
Samuel, G
通讯作者：
Samuel, G
影响因子：
7.4
作者：
Ahmad, Shakoor;Veyrat, Nathalie;Ton, Jurriaan
通讯作者：
Ton, Jurriaan
影响因子：
11.4
作者：
Leach, Kristen A.;Tran, Thu M.;Braun, David M.
通讯作者：
Braun, David M.