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To uncover the mechanisms that underlie the chlorina phenotype of the tea plant, this study employs morphological, biochemical, transcriptomic, and iTRAQ-based proteomic analyses to compare the green tea cultivar LJ43 and the yellow-leaf tea cultivar ZH1. ZH1 exhibited the chlorina phenotype, with significantly decreased chlorophyll content and abnormal chloroplast development compared with LJ43. ZH1 also displayed higher theanine and free amino acid content and lower carotenoid and catechin content. Microarray and iTRAQ analyses indicated that the differentially expressed genes and proteins could be mapped to the following pathways: ‘phenylpropanoid biosynthesis,’ ‘glutathione metabolism,’ ‘phenylalanine metabolism,’ ‘photosynthesis,’ and ‘flavonoid biosynthesis.’ Altered gene and protein levels in these pathways may account for the increased amino acid content and reduced chlorophyll and flavonoid content of ZH1. Altogether, this study combines transcriptomic and proteomic approaches to better understand the mechanisms responsible for the chlorina phenotype. [ABSTRACT FROM AUTHOR]

Photosynthesis, the primary source of plant biomass, is important for plant growth and crop yield. Chlorophyll is highly abundant in plant leaves and plays essential roles in photosynthesis. We recently isolated a chlorophyll-deficient mutant ( cde1 ) from ethyl methanesulfonate (EMS) mutagenized Brassica napus . Herein, quantitative proteomics analysis using the iTRAQ approach was conducted to investigate cde1 -induced changes in the proteome. We identified 5069 proteins from B. napus leaves, of which 443 showed differential accumulations between the cde1 mutant and its corresponding wild-type. The differentially accumulated proteins were found to be involved in photosynthesis, porphyrin and chlorophyll metabolism, biosynthesis of secondary metabolites, carbon fixation, spliceosome, mRNA surveillance and RNA degradation. Our results suggest that decreased abundance of chlorophyll biosynthetic enzymes and photosynthetic proteins, impaired carbon fixation efficiency and disturbed redox homeostasis might account for the reduced chlorophyll contents, impaired photosynthetic capacity and increased lipid peroxidation in this mutant. Epigenetics was implicated in the regulation of gene expression in cde1 , as proteins involved in DNA/RNA/histone methylation and methylation-dependent chromatin silencing were up-accumulated in the mutant. Biological significance Photosynthesis produces more than 90% of plant biomass and is an important factor influencing potential crop yield. The pigment chlorophyll plays essential roles in light harvesting and energy transfer during photosynthesis. Mutants deficient in chlorophyll synthesis have been used extensively to investigate the chlorophyll metabolism, development and photosynthesis. However, limited information is available with regard to the changes of protein profiles upon chlorophyll deficiency. Here, a combined physiological, histological, proteomics and molecular analysis revealed several important pathways associated with chlorophyll deficiency. This work provides new insights into the regulation of chlorophyll biosynthesis and photosynthesis in higher plants and these findings may be applied to genetic engineering for high photosynthetic efficiency in crops. [ABSTRACT FROM AUTHOR]

Summary: A major gene controlling chlorophyll deficiency (phenotyped by yellow leaf color, yl) in sunflower was identified and mapped in an F2 population derived from a cross between two breeding lines. Greenness degree was scored by a hand-held chlorophyll meter in the F2 population. Leaf tissue from the parents, F1 hybrids, and some F2 progenies were also sampled to determine the chlorophyll content. All F1 plants had normal green leaf color and the segregation of the plants in the F2 population fits the monogenic ratio (χ (3:1) 2=0.03, p>0.9), indicating that leaf color is a monogenic trait with normal green dominant over yellow leaf color in this population. The contents of chlorophyll a, chlorophyll b, and total chlorophyll in the yellow-leafed lines were reduced by 41.6%, 53.5%, and 44.3%, respectively, in comparison with those in the green-leafed lines. Genetic mapping with molecular markers positioned the gene, yl, to linkage group 10 of sunflower. An SSR marker, ORS 595, cosegregated with yl, and a TRAP marker, B26P17ga5-300, was linked to yl with a genetic distance of 4.2cM. The molecular marker tightly linked to the chlorophyll deficiency gene will provide insight into the process of chlorophyll metabolism in sunflower. [Copyright &y& Elsevier]

In Australia, some trees of the mangrove, Avicennia marina, growing in a chronic oil polluted site, produce chlorophyll deficient (albino) propagules. We tested the hypothesis that albinism was due to an oil-induced mutant allele that controls photosynthesis. We determined whether there are genetic differences between normal and chlorophyll deficient propagules. Four gene regions (nuclear 18S–26S cistron; chloroplast - trn H -psb A, rsp 16 and mat K) were sequenced and analysed for normal and albino propagules. Mutations occurred in both nuclear (ITS) and coding chloroplast (mat K) genes of albino propagules. There were 10 mutational differences between normal and albino propagules in the mat K samples. Analysis of molecular variation (AMOVA) of the mat K dataset indicated highly significant genetic differentiation between normal and albino propagules. Our study suggests for the first time that PAHs from a chronic oil polluted site resulted in mutations in both nuclear and chloroplast genes, resulting in the production of albino propagules. [ABSTRACT FROM AUTHOR]