Ethylene-dependent and -independent pathways controlling floral abscission are revealed to converge using promoter::reporter gene constructs in the ida abscission mutant
Ethylene-dependent and -independent pathways controlling floral abscission are revealed to converge using promoter::reporter gene constructs in the ida abscission mutant
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DOI：
10.1093/jxb/erl130
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发表时间：
2006-11-01
影响因子：
6.9
通讯作者：
Aalen, Reidunn B.
中科院分区：
文献类型：
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作者：
Butenko, Melinka A.;Stenvik, Grethe-Elisabeth;Aalen, Reidunn B.
拟南芥（Arabidopsis thaliana）的花器官脱落过程可由乙烯调控，涉及许多参与细胞分离的基因。在脱落过程中，有一个基因是绝对必需的，那就是IDA，因为IDA突变体在脱落过程中被完全阻断。为了阐明调控花脱落的遗传途径，在ida突变体背景下研究了花脱落区表达的分子标记。利用具有启动子-报告基因构建的植物，包括一种新的花脱落相关基因（FAA）的启动子，该基因编码一种假定的单链结合蛋白（BASIL）、几丁质酶（CHIT::GUS）和纤维素酶（BAC::GUS），结果表明IDA在脱落过程的最后步骤中起作用。与野生型植物相比，这些标记以及编码受体样激酶的HAESA在ida中的时间表达模式不受影响；这表明在脱落过程中有不同的调控途径。然而，与BASIL相比，CHIT::GUS和BAC::GUS在ida背景下的表达诱导要弱得多，这与突变体中病原体相关反应的减少和细胞壁完全溶解的缺乏一致。IDA编码一种推定的分泌肽配体，与HAESA在花脱落区似乎具有相同的表达模式。最后，为了阐明乙烯的作用，比较了野生型和乙烯不敏感突变体etr1-1中IDA::GUS的表达。在etr1-1中观察到类似的时间模式，但受限制的空间表达模式，这表明IDA和乙烯调控的途径是平行的，但在某种程度上是相互依存的。
The process of floral organ abscission in Arabidopsis thaliana can be modulated by ethylene and involves numerous genes contributing to cell separation. One gene that is absolutely required for abscission is INFLORESCENCE DEFICIENT IN ABSCISSION, IDA, as the ida mutant is completely blocked in abscission. To elucidate the genetic pathways regulating floral abscission, molecular markers expressed in the floral abscission zone have been studied in an ida mutant background. Using plants with promoter-reporter gene constructs including promoters of a novel FLORAL ABSCISSION ASSOCIATED gene (FAA) encoding a putative single-stranded binding protein (BASIL), chitinase (CHIT::GUS) and cellulase (BAC::GUS), it is shown that IDA acts in the last steps of the abscission process. These markers, as well as HAESA, encoding a receptor-like kinase, were unaffected in their temporal expression patterns in ida compared with wild-type plants; thus showing that different regulatory pathways are active in the abscission process. In contrast to BASIL, CHIT::GUS and BAC::GUS showed, however, much weaker induction of expression in an ida background, consistent with a reduction in pathogen-associated responses and a lack of total dissolution of cell walls in the mutant. IDA, encoding a putative secreted peptide ligand, and HAESA appeared to have identical patterns of expression in floral abscission zones. Lastly, to address the role of ethylene, IDA::GUS expression in the wild type and the ethylene-insensitive mutant etr1-1 was compared. Similar temporal patterns, yet restricted spatial expression patterns were observed in etr1-1, suggesting that the pathways regulated by IDA and by ethylene act in parallel, but are, to some degree, interdependent.