Plant degreening: evolution and expression of tomato (Solanum lycopersicum) dephytylation enzymes |
| |
Authors: | Bruno Silvestre Lira Nathalia de Setta Daniele Rosado Juliana Almeida Luciano Freschi Magdalena Rossi |
| |
Institution: | 1. Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP, Brazil;2. Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André, SP, Brazil |
| |
Abstract: | Chlorophyll is the most abundant pigment on earth and even though it is known that its high photo-excitability necessitates a tight regulation of its degradation pathway, to date there are still several steps in chlorophyll breakdown that remain obscure. In order to better understand the ‘degreening’ processes that accompany leaf senescence and fruit ripening, we characterized the enzyme-encoding genes involved in dephytylation from tomato (Solanum lycopersicum). A single pheophytinase (PPH) gene and four chlorophyllase (CLH) genes were identified in the tomato genome. A phenetic analysis revealed two groups of CLHs in eudicot species and further evolutionary analysis indicated that these enzymes are under diverse selection pressures. A comprehensive expression profile analysis also suggested functional specificity for these dephytylating enzymes. The integrated analysis allows us to propose three general roles for chlorophyll dephytylation: i) PPH, which is under high selective constraint, is responsible for chlorophyll degradation during developmentally programed physiological processes; ii) Group I CLHs, which are under relaxed selection constraint, respond to environmental and hormonal stimuli and play a role in plant adaptation plasticity; and iii) Group II CLHs, which are also under high selective constraint, are mostly involved in chlorophyll recycling. |
| |
Keywords: | ABA abscisic acid Chl chlorophyll Chlide chlorophyllide CLH chlorophyllase dN non-synonymous distance dS synonymous distance gf green flesh mutant LTR likelihood ratio test MS Murashige and Skoog media Nc number of codons PAO pheophorbide a oxygenase PAR photosynthetically active radiation pFCC primary fluorescent chlorophyll catabolite Pheide pheophorbide Pheo pheophytin PPH pheophytinase RCC red chlorophyll catabolite SAG12 senescence associated gene 12 SE standard error SGR stay green protein UTR untranslated regions |
本文献已被 ScienceDirect 等数据库收录! |
|