Department of Molecular Biology and Genetics, Aarhus University, Forsoegsvej 1, 4200 Slagelse, Denmark.
Plant Mol Biol. 2013 Aug;82(6):603-22. doi: 10.1007/s11103-013-0013-8. Epub 2013 Jan 25.
Senescence is a developmental process which in annual crop plants overlaps with the reproductive phase. Senescence might reduce crop yield when it is induced prematurely under adverse environmental conditions. This review covers the role of senescence for the productivity of crop plants. With the aim to enhance productivity, a number of functional stay-green cultivars have been selected by conventional breeding, in particular of sorghum and maize. In many cases, a positive correlation between leaf area duration and yield has been observed, although in a number of other cases, stay-green cultivars do not display significant effects with regards to productivity. In several crops, the stay-green phenotype is observed to be associated with a higher drought resistance and a better performance under low nitrogen conditions. Among the approaches used to achieve stay-green phenotypes in transgenic plants, the expression of the IPT gene under control of senescence-associated promoters has been the most successful. The promoters employed for senescence-regulated expression contain cis-elements for binding of WRKY transcription factors and factors controlled by abscisic acid. In most crops transformed with such constructs the stay-green character has led to increased biomass, but only in few cases to increased seed yield. A coincidence of drought stress resistance and stay-green trait is observed in many transgenic plants.
衰老是一个发育过程，在一年生作物中与生殖阶段重叠。在不利的环境条件下过早诱导衰老时，可能会降低作物的产量。本综述涵盖了衰老对作物生产力的作用。为了提高生产力，许多具有功能的常绿品种已经通过传统的选育方法得到了选择，特别是高粱和玉米。在许多情况下，已经观察到叶面积持续时间和产量之间存在正相关，尽管在许多其他情况下，常绿品种在生产力方面没有显示出显著的效果。在几种作物中，常绿表型与更高的抗旱性和在低氮条件下更好的表现相关。在用于实现转基因植物常绿表型的方法中，IPT 基因在与衰老相关的启动子控制下的表达是最成功的。用于衰老调控表达的启动子包含结合 WRKY 转录因子和由脱落酸控制的顺式元件。在许多转化为这类构建体的作物中，常绿特征导致生物量增加，但只有在少数情况下导致种子产量增加。在许多转基因植物中观察到干旱胁迫抗性和常绿特性的巧合。
