The Regulation of Compound Leaf Development in Tomato

番茄复叶发育调控

• 批准号: 9983063
• 负责人: Neelima Sinha
• 金额: $ 33万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-04-01 至 2003-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9983063&HistoricalAwards=false
• 关键词: Regulation; Compound; Leaf; Development; Tomato

Sinha9983063The purpose of this research is to understand how compound leaves differ from simple leaves and to elucidate the developmental steps that give rise to this complex leaf form. The starting point of this analysis is the finding that Class 1 homeobox genes like KNOTTED1 (KNOX1 genes) are expressed only in the shoot apical meristem (SAM) and unexpanded shoots, and not in the incipient leaf primordium (P0), of simple leaf producing apices in both dicots and monocots. Over-expression of these genes is sufficient to cause leaf lobing and ectopic meristem formation. However, in compound leaf producing SAMs in tomato, the KNOX1 genes (like LeT6 and TKN1) are expressed both in the SAM and in emerging and developing leaf primordia. This suggests that KNOX1 genes may provide a degree of indeterminacy to the leaf primordia in tomato, thereby leading to an extended stage of morphogenesis and a more complex leaf form. This project will identify the proteins that interact with LeT6 to provide DNA binding specificity and organ specific gene regulation, and the downstream targets of LeT6 regulation. Expression analyses in the tomato leaf mutations suggest that trans-acting factors at the LeT6 promoter, targets of LeT6, and other genes that may act as LeT6 partners in transcriptional regulation would lead to the identification of other key genes in compound leaf development. Preliminary data suggests that LeT6 may regulate the expression of the PHANTASTICA homolog in tomato, which in turn may regulate other KNOX1 genes. The following questions will be addressed. What are the downstream targets of the KNOX1 genes like LeT6? Do the KNOX1 genes act in a complex with other transcription factors (TFs)? How are the levels of KNOX1 genes like LeT6 regulated in tomato shoot apices? What role does PHAN play in the regulation of KNOX1 gene expression in tomato shoot meristems and leaves? Are the expression patterns of PHAN and KNOX1 genes complementary in tomato apices (as shown for simple leaf producing apices)? Does PHAN expression in tomato predict sites of leaflet initiation (as suggested for the simple leaved Antirrhinum and Arabidopsis)? A careful study of KNOX1 genes like LeT6 and TKN1, PHAN, and their regulatory relationships will allow an understanding of the developmental steps that give rise to the complex leaf form in compound leaves.

Sinha9983063这项研究的目的是了解复合叶子与简单叶子的不同之处，并阐明产生这种复杂叶子形式的发育步骤。 该分析的出发点是发现 1 类同源框基因，如 KNOTTED1（KNOX1 基因）仅在双子叶植物和单子叶植物的单子叶产生顶端的茎尖分生组织 (SAM) 和未展开的芽中表达，而不在初期叶原基 (P0) 中表达。这些基因的过度表达足以引起叶裂和异位分生组织形成。 然而，在番茄中产生复合叶的 SAM 中，KNOX1 基因（如 LeT6 和 TKN1）在 SAM 以及正在形成和发育的叶原基中表达。 这表明 KNOX1 基因可能为番茄的叶原基提供一定程度的不确定性，从而导致形态发生阶段的延长和更复杂的叶子形态。 该项目将鉴定与LeT6相互作用以提供DNA结合特异性和器官特异性基因调控的蛋白质，以及LeT6调控的下游靶标。 番茄叶突变的表达分析表明，LeT6 启动子处的反式作用因子、LeT6 的靶标以及可能在转录调控中充当 LeT6 伙伴的其他基因将导致复合叶发育中其他关键基因的鉴定。 初步数据表明，LeT6 可能调节番茄中 PHANTASTICA 同源物的表达，进而可能调节其他 KNOX1 基因。 将解决以下问题。 LeT6 等 KNOX1 基因的下游靶标是什么？ KNOX1 基因是否与其他转录因子 (TF) 形成复合体？ 番茄芽尖中 KNOX1 基因（如 LeT6）的水平是如何调节的？ PHAN 在番茄芽分生组织和叶片 KNOX1 基因表达的调控中发挥什么作用？ 番茄顶端中 PHAN 和 KNOX1 基因的表达模式是否互补（如简单产叶顶端所示）？ 番茄中的 PHAN 表达是否可以预测小叶起始的位点（如单叶金鱼草和拟南芥所建议的那样）？ 对 LeT6 和 TKN1、PHAN 等 KNOX1 基因及其调控关系的仔细研究将有助于了解复合叶中复杂叶形的发育步骤。