Anatomical distribution of abnormally high levels of starch in HLB-affected Valencia orange trees
Anatomical distribution of abnormally high levels of starch in HLB-affected Valencia orange trees
复制标题
DOI：
10.1016/j.pmpp.2009.09.004
复制
发表时间：
2009-01-01
影响因子：
2.7
通讯作者：
Albrigo, Gene
中科院分区：
文献类型：
--
作者：
Etxeberria, Ed;Gonzalez, Pedro;Albrigo, Gene
柑橘黄龙病（HLB或柑橘绿化）的特征在于叶片中异常水平的淀粉积累以及其他症状。这种情况表明碳水化合物源库关系的不平衡，这反过来可能对HLB树的整体健康和未来的疾病管理策略产生直接影响。用光，扫描和透射电子显微镜，我们调查了整个树的碳水化合物分配不平衡的程度。在所有的气生组织中，淀粉积累在HLB影响的树木远远超过HLB阴性对照树。淀粉在叶片和叶柄的光合细胞、韧皮部和维管薄壁组织中大量积累。在茎中，淀粉通常观察到木质部薄壁组织和在HLB影响的树木，但没有从对照样品的外胚层。与此相反，从HLB影响的树木的根耗尽淀粉，而从对照树的根含有大量的淀粉沉积。这些数据支持这样一种观点，即在整个柑橘树中观察到的碳水化合物分配的实质性变化可能不仅是HLB感染的结果，而且其本身也是受感染树木迅速衰退和死亡的原因。(C)2009年由Elsevier Ltd.出版
The citrus disease Huanglongbing (HLB or citrus greening) is characterized, among other symptoms, by extraordinary levels of starch accumulation in leaves. This condition denotes imbalances in carbohydrate source sink relationship which in turn may have direct implications in the overall health of HLB-trees and in future strategies to manage the disease. Using light, scanning, and transmission electron microscopy we investigated the extent of carbohydrate partitioning imbalances throughout the tree. In all aerial tissues, starch accumulation in HLB-affected trees far exceeded that of HLB-negative control trees. Starch accumulated extensively in photosynthetic cells as well as phloem elements and vascular parenchyma in leaves and petioles. In stems, starch was commonly observed in xylem parenchyma and in the phelloderm of HLB-affected trees but absent from control samples. In contrast, roots from HLB-affected trees were depleted of starch whereas roots from control trees contain substantial starch deposits. The data supports the notion that the substantial changes in carbohydrate partitioning observed throughout the citrus tree may not only be a result of HLB infection, but in itself, a cause for the rapid decline and death of infected trees. (C) 2009 Published by Elsevier Ltd.