Plant functional genomics & plant breeding
Reza Shirzadian Khorramabad
Abstract
Leaf senescence constitutes the last stage of leaf development in plants and proceeds through a highly regulated program in order to redistribution of micro- and macro-nutrients from the senescing leaves to the developing/growing plant organs. Initiation and progression of leaf senescence is accompanied ...
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Leaf senescence constitutes the last stage of leaf development in plants and proceeds through a highly regulated program in order to redistribution of micro- and macro-nutrients from the senescing leaves to the developing/growing plant organs. Initiation and progression of leaf senescence is accompanied by massive sequential alterations at various levels of leaf biology including leaf morphology and physiology, cell metabolism and structure, and gene transcription. In this regard, comprehensive expression analysis of senescence-associated genes (SAGs) and the identification of leaf senescence related mutants has revealed that leaf senescence is a complex genetically controlled program. In this review, we present important findings about the molecular genetic mechanisms underlying leaf senescence in various plants with a main focus on the model plant Arabidopsis thaliana. Functional analysis of leaf senescence mutants has provided new insights into the key processes that regulate the onset and progression of leaf senescence, thus allowing categorization of the various regulatory factors into several signalling pathways.
Plant functional genomics & plant breeding
Seyyed Hamidreza Hashemi; Ghorbanali Nematzadeh; Hossein Askari; Yousef Ghasemi
Abstract
DNA methylation as an epigenetic mediator plays the important role in spatial and temporal gene regulation and ensures the stability and the plasticity of organism. In this investigation, methylation sensitive amplification polymorphism (MSAP) were assessed in CCGG sites on a halophytic plant, Aeluropuslittoralis ...
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DNA methylation as an epigenetic mediator plays the important role in spatial and temporal gene regulation and ensures the stability and the plasticity of organism. In this investigation, methylation sensitive amplification polymorphism (MSAP) were assessed in CCGG sites on a halophytic plant, Aeluropuslittoralis in response to different temperature stresses including freezing, low and high temperatures. A combination of 13 primers were able to produce 500 bands, of which 74%, 20.8% and 5.2% were of type I (non methylated fragments), type II (CpG methylated fragments) and type III (CpCpG methylated fragments), respectively. Among these bands, 130 bands were methylated fragments with the highest occurrence of methylation at CpG internal cytosine. The results showed that up to 2% of all methylated bands were polymorphic, which belonged to types II and III. Highest levels of methylation alternations were detected under high and freezing temperatures. The results suggest that apart from cis regulatory logic plant response to the environmental temperatures may be regulated by methylation of CCGG sites of stress-related loci.