Pollen-pistil Interactions in the Genus Nicotiana

烟草属花粉-雌蕊相互作用

• 批准号: 9604645
• 负责人: Bruce McClure
• 金额: $ 36万
• 依托单位: University of Missouri-Columbia
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-04-01 至 2001-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9604645&HistoricalAwards=false
• 关键词: Pollen; pistil; Interactions; Genus; Nicotiana

McClure 9604645 Pollen-pistil interactions provide an important avenue for controlling plant reproduction. The factors controlling intraspecific and interspecific pollen recognition in the genus Nicotiana provide an excellent system for exploring these interactions. A great deal is known about S-RNase mediated intraspecific pollen recognition in self-incompatible Nicotiana alata. Furthermore, the interspecific crossing relationships between N. alata and its self-compatible relatives have been well described. Both types of pollen recognition clearly entail interactions between the pollen and the pistil. This research project uses biochemical and molecular biological tools to understand the molecular details of these interactions. In the previous funding period, cloned S-RNase genes from N. alata were expressed in transgenic plants to examine their role in controlling pollination. The key results were: 1) that S-RNases control the specificity of intraspecific pollination, 2) that recognition information is diffusely encoded in the S-RNase molecule, 3) that at least three genetically distinct mechanisms contribute to controlling interspecific pollination between N. alata and its self-compatible relatives, and 4) that S-RNase was implicated in interspecific pollen recognition and rejection. These results are important because they imply that S-RNase helps to define a window of genetic relatedness for compatible pollination. It has a role in rejecting self-pollen, and thus prevents inbreeding. It also has a role in rejecting interspecific pollen, and so acts to prevent very wide crosses. The major goals in this new proposal are: 1) to identify and characterize non-SRNase factors that contribute to pollen recognition, and 2) to examine the specificity of RNase dependent interspecific pollen rejection. One putative factor has already been identified by differential cDNA cloning. This new sequence will be characterized using immunological and transgenic plant methods. The cDNA cloning appr oach will be extended to identify further non-S-RNase factors related to pollen recognition. The specificity of interspecific pollen recognition will be addressed by comparing the pollination behavior of transgenic plants expressing a bacterial RNase with plants expressing S-RNase or recognition defective S-RNase. By understanding the natural mechanisms that control intraspecific and interspecific pollen recognition in the genus Nicotiana, these studies may contribute to efforts to artificially manipulate the breeding behavior of economically important plants.

McClure 9604645花粉与雌蕊的相互作用为控制植物繁殖提供了重要途径。控制烟草属种内和种间花粉识别的因素为探索这些相互作用提供了一个很好的系统。关于S核糖核酸酶介导的自交不亲和烟草种内花粉识别的研究很多。此外，翅果与其自交亲和近缘之间的种间杂交关系也得到了很好的描述。这两种类型的花粉识别显然都需要花粉和雌蕊之间的相互作用。这项研究项目使用生化和分子生物学工具来了解这些相互作用的分子细节。在之前的资助期间，从翅果中克隆的S核糖核酸酶基因在转基因植株中表达，以检测它们在控制授粉中的作用。主要结果是：1)S核糖核酸酶控制种内授粉的专一性，2)识别信息在S核糖核酸酶分子中广泛编码，3)至少有3种不同的遗传机制控制了翅果与其自交亲和近缘的种间授粉，以及4)S核糖核酸酶参与了种间花粉的识别和排斥。这些结果很重要，因为它们暗示S核糖核酸酶有助于确定亲和授粉的遗传亲缘关系窗口。它具有排斥自交花粉的作用，从而防止近亲繁殖。它还起到拒绝种间花粉的作用，因此可以防止远缘杂交。这一新建议的主要目标是：1)鉴定和表征与花粉识别有关的非SRNase因子；2)研究依赖RNase的种间花粉排斥反应的特异性。通过差异克隆的方法已经确定了一个可能的因子。这一新序列将使用免疫学和转基因植物方法进行表征。这一克隆方法将进一步用于鉴定与花粉识别相关的非S核糖核酸酶因子。通过比较表达细菌核糖核酸酶的转基因植物与表达S-核糖核酸酶或识别缺陷的S-核糖核酸酶的植株的授粉行为，探讨种间花粉识别的特异性。通过了解控制烟草属种内和种间花粉识别的自然机制，这些研究可能有助于人工操纵重要经济植物的繁殖行为。