Mao L, Begum D, Chuang H W, Budiman M A, Szymkowiak E J, Irish E E, Wing R A
Clemson University Genomics Institute, South Carolina 29634, USA.
Nature. 2000 Aug 24;406(6798):910-3. doi: 10.1038/35022611.
Abscission is a universal and dynamic process in plants whereby organs such as leaves, flowers and fruit are shed, both during normal development, and in response to tissue damage and stress. Shedding occurs by separation of cells in anatomically distinct regions of the plant, called abscission zones (AZs). During abscission, the plant hormone ethylene stimulates cells to produce enzymes that degrade the middle lamella between cells in the AZ. The physiology and regulation of abscission at fully developed AZs is well known, but the molecular biology underlying their development is not. Here we report the first isolation of a gene directly involved in the development of a functional plant AZ. Tomato plants with the jointless mutation fail to develop AZs on their pedicels and so abscission of flowers or fruit does not occur normally. We identify JOINTLESS as a new MADS-box gene in a distinct phylogenetic clade separate from those functioning in floral organs. We propose that a deletion in JOINTLESS accounts for the failure of activation of pedicel AZ development in jointless tomato plants.
脱落是植物中一个普遍且动态的过程，在此过程中，诸如叶子、花朵和果实等器官会在正常发育期间以及对组织损伤和胁迫作出反应时脱落。脱落是通过植物中解剖学上不同区域的细胞分离来实现的，这些区域称为脱落区（AZs）。在脱落过程中，植物激素乙烯刺激细胞产生酶，这些酶会降解脱落区细胞之间的中层。成熟脱落区的脱落生理和调控机制已为人熟知，但其发育背后的分子生物学机制尚不清楚。在此，我们报告首次分离出一个直接参与功能性植物脱落区发育的基因。具有无节突变的番茄植株在其花梗上无法发育出脱落区，因此花朵或果实的脱落不能正常发生。我们将无节基因鉴定为一个新的MADS-box基因，它位于一个与在花器官中起作用的基因不同的系统发育分支中。我们认为，无节番茄植株中无节基因的缺失导致花梗脱落区发育无法激活。
