Integrated Studies on the Cellular, Physiological and Developmental Roles Played by Higher Plant Plasmodesmata

该奖项支持高等植物胞间连丝（plasmodesmata， PD）的分子和细胞特性研究。胞间连丝参与蛋白质和核酸大分子运输的能力将使用多种技术进行研究。功能和突变病毒运动蛋白（MPs）将用于显微注射研究，以检查这些MPs，它们的同源病毒RNA （vRNA）和间连丝之间相互作用的分子基础。这种分子病毒学和细胞生物学的强大结合为鉴定病毒-植物宿主特异性的分子决定因素以及阐明病毒MPs上的功能域开辟了道路。四种植物病毒的MPs将用于这些研究；红三叶草坏死花叶病毒（RCNMV）、烟草花叶病毒（TMV）、大麻花叶病毒（SHMV）和黄瓜花叶病毒（CMV）。为了更全面地了解胞间连丝在植物发育和生理功能中的作用，对其亚结构成分（蛋白质）进行分离、克隆和测序是十分重要的。为此，将从转TMV MP的烟草植株中分离出次生PD。TMV mp诱导的碳分配改变的生理和分子基础将通过一系列实验方法进行研究。在TMV - MP转基因烟草中观察到的根冠比降低将成为这些研究的诊断依据。组织嫁接实验将允许识别参与这种重新分配现象的植物组织。通过PD的大分子（蛋白质）运输在植物发育中起作用的假设将通过玉米knot -1突变体系统进行验证。这些关于病毒MP-PD相互作用的分子决定因素的研究结果将使我们对PD大分子运输的要求有更深入的了解。PD蛋白的纯化和鉴定将为这种独特的胞间细胞器的详细结构/功能分析提供基础。详细了解TMV MP诱导的碳分配改变的分子事件将为鉴定和研究介导从组织到整个植物水平生理过程整合的内源信号/调节途径提供基础。所有这些关于大分子通过PD运输的数据将有助于验证植物作为超细胞生物而不是多细胞生物的假设。＊＊＊

9406974 Lucas This award supports studies on the molecular and cellular characterization of higher plant plasmodesmata (PD). The capacity of plasmodesmata to engage in macromolecular trafficking of proteins and nucleic acids will be studies using a combination of techniques. Functional and mutant viral movement proteins (MPs) will be used in microinjection studies to examine the molecular basis of the interaction between these MPs, their cognate viral RNA (vRNA), and plasmodesmata. This powerful combination of molecular virology and cell biology opens the way for the identification of the molecular determinants of virus-plant host specificity, as well as the elucidation of the functional domains on the viral MPs. The MPs of four plant viruses will be used in these studies; red clover necrotic mosaic virus (RCNMV), tobacco mosaic virus (TMV), sunn hemp mosaic virus (SHMV) and cucumber mosaic virus (CMV). In order to more fully understand the role played by plasmodesmata in the orchestration of plant development and physiological function, it is important that the sub-structural component (proteins) be isolated, cloned and sequenced. To this end, secondary PD will be isolated from TMV MP transgenic tobacco plants. The physiological and molecular basis for the TMV MP-induced alteration in carbon partitioning will be investigated using a range of experimental approaches. The reduction in root-to-shoot ratios observed in TMV MP transgenic tobacco will form the diagnostic basis for these studies. Tissue grafting experiments will permit the identification of the plant tissue involved in this reallocation phenomenon. The hypothesis that macromolecular (protein) trafficking through PD plays a role in plant development will be tested using the maize Knotted-1 mutant system. Results from these studies on the molecular determinants of viral MP-PD interaction will provide us with greater insights into the requirements for PD macromolecular trafficking. Purifica tion and identification of PD proteins will provide the foundation for a detailed structure/function analysis of this unique intercellular organelle. Details on the molecular events underlying the TMV MP- induced alteration in carbon partitioning will provide the foundation for the identification and study of endogenous signal/regulatory pathways that mediate in the integration of physiological processes from the tissue to the whole plant level. All such data on macromolecular transport through PD will contribute to testing the hypothesis that plants function as supracelluar rather than multicellular organisms. ***