Gene Regulation of Dormancy in Avena fatua Embryos

9318055 Foley本项目的目的是阐明种子休眠和后熟诱导的休眠解除的生理基础。本项目的目的是利用互补的分子和遗传学方法来研究休眠/打破休眠的分子基础。对种子休眠的研究主要是通过研究休眠的打破来进行的，这使得打破休眠与萌发的解释变得复杂起来。这里描述的分子和遗传方法是不同的，因为它们主要集中在休眠的维持上。要检验的假设是，在休眠胚胎中表达的特定基因或其产物将种子维持在休眠状态。这些基因的表达在休眠胚胎的后成熟过程中被抑制，这有利于随后的萌发。利用体内和体外翻译程序，已经鉴定出大约10种多肽存在于吸胀后不久的休眠但不成熟的胚胎中。建立了休眠特异的重组文库，筛选出16个休眠特异的阳性克隆，其表达受后熟调控。这些克隆将进一步鉴定它们的一般表达和核酸序列。为了补充这一方法，有人建议寻找与休眠性状相关的主要基因的分子标记，并同时评估/完善解释法特瓦夜蛾休眠的暂定遗传模型。此外，为了证实基于群体分离分析的F2群体的任何遗传模型，并更好地理解休眠的遗传，建议培育出休眠程度不同的高世代F2衍生品系并进行遗传评估。这种分子和遗传方法应该为理解植物发育停滞阶段的生理基础提供重要信息。***

9318055 Foley The goal of this project is to elucidate the physiological basis for seed dormancy and afterripening-induced breaking of dormancy. The aim of this project is to investigate the molecular basis for dormancy/breaking dormancy using complementary molecular and genetic approaches. Research on seed dormancy has been approached mainly by studying breaking of dormancy which complicates interpretation by confounding breaking of dormancy with germination. The molecular and genetic approaches described herein are distinct in that they focus primarily on maintenance of dormancy. The hypothesis to be tested states that specific genes or their products which are expressed in dormant embryos maintain seed in the dormant state. The expression of these genes is repressed during afterripening of dormant embryos which facilitates subsequent germination. Using in vivo and in vitro translation procedures, about 10 polypeptides have been identified that occur in dormant but not afterripened embryos soon after imbibition. A dormancy-specific recombinant library has been developed and sixteen putative dormancy-specific positive clones, whose expression is modulated by afterripening, have been selected. These clones will be further characterized as to their general expression and nucleic acid sequence. To complement this approach it is proposed that molecular markers be identified for major genes associated with the dormancy trait and simultaneously evaluate/refine the tentative genetic model explaining dormancy in A. fatua. In addition, to confirm any genetic modelbased on F2 populations derived for bulk segregant analysis and to better understand the inheritance of dormancy it is proposed that advanced-generation, F2-derived lines that vary in their degree of dormancy be developed and genetically evaluated. This molecular and genetic approach should provide significant information toward understanding the physiological basis for this arrested stage of plant development. ***