Carotenoid accumulation in Japanese apricot (Prunus mume Siebold & Zucc.): molecular analysis of carotenogenic gene expression and ethylene regulation

To elucidate the regulatory mechanisms of carotenogenesis in Japanese apricot (Prunus mume Siebold & Zucc.), the relationships between carotenoid accumulation and the expression of the carotenogenic genes, phytoene synthase (PmPSY-1), phytoene desaturase (PmPDS), zeta-carotene desaturase (PmZDS), lycopene beta-cyclase (PmLCYb), lycopene epsilon-cyclase (PmLCYe), beta-carotene hydroxylase (PmHYb), and zeaxanthin epoxidase (PmZEP), were analyzed in two cultivars with different ripening traits, 'Orihime' and 'Nanko.' In 'Orihime' fruits, large amounts of carotenoids accumulated on the tree, concomitant with the induction of PmPSY-1 and the downstream carotenogenic genes PmLCYb, PmHYb, and PmZEP. In 'Nanko' fruits, carotenoids accumulated mainly after harvest, correlating with an appreciable induction of PmPSY-1 expression, but the downstream genes were not notably induced, which may explain the lower total carotenoid content in 'Nanko' than in 'Orihime.' In both cultivars, a decrease in PmLCYe expression and increased or constant PmLCYb expression could cause the metabolic shift from beta,epsilon-carotenoid synthesis to beta,beta-carotenoid synthesis that occurs as ripening approaches. Next, the effects of ethylene on the expression of PmPSY-1 and carotenoid accumulation were investigated in 'Nanko' fruits treated with propylene or 1-methylcyclopropene (1-MCP). Propylene treatment induced both ethylene production and carotenoid accumulation. PmPSY-1 was constitutively expressed, but propylene treatment accelerated its induction. 1-MCP treatment caused a slight inhibition of carotenoid accumulation along with the repression, although not complete, of PmPSY-1. Collectively, although PmPSY-1 expression was not exclusively regulated by ethylene, both the notable induction of PmPSY-1 accelerated by ethylene and the subsequent induction of the downstream carotenogenic genes, especially PmLCYb, could be necessary for the massive carotenoid accumulation that occurs during ripening. Furthermore, the switch from PmLCYe expression to PmLCYb expression could cause beta,beta-carotenoid accumulation in both Japanese apricot cultivars.     

Chlorophyll and carotenoid patterns in olive fruits, Olea europaea Cv. arbequina

In olive fruits of the cultivar Arbequina, the chlorophyll pigments decrease significantly throughout ripening, while the carotenoids decrease more gradually and discontinuously. There is no degradation of the carotenoid fraction in stages before complete ripeness. The presence of esterified xanthophylls exclusively in this variety suggests that the chloroplast pigment metabolism is different from that in other olive varieties studied previously. There are increases of specific carotenoids, violaxanthin, neoxanthin, antheraxanthin, lutein epoxide, and esterified xanthophylls between the light green and yellowish green ripening stages. Such increases are related to the detection of precursor carotenoids (phytofluene and xi-carotene) in the yellowish green stage. Chlorophyllides (a and b) and alpha-carotene have also been detected exclusively in this variety. Quantitatively, the drastic change in color between light green and yellowish green ripening stages characteristic of this variety can be explained by the considerable reduction found in the chlorophylls/carotenoids ratio. The study of the pigments present in skin and pulp has shown that the pattern of carotenoid distribution differs depending on the fruit part concerned.     

Color in fruit of the genus actinidia: carotenoid and chlorophyll compositions.

The carotenoid and chlorophyll contents in the fruit of four species of Actinidia were measured to determine the chemical basis of color in kiwifruit and related Actinidia species. The species studied were the two commercial fruits Actinidia deliciosa cv. Hayward and a yellow-fleshed genotype Actinidia chinensis cv. Hort16A (known commercially as ZESPRI Gold kiwifruit), the yellow fruit of Actinida polygama, and the orange fruit of Actinida macrosperma. As reported previously, ripe fruit of A. deliciosa contain chlorophylls a and b and the carotenoids normally associated with photosynthesis, beta-carotene, lutein, violaxanthin, and 9'-cis-neoxanthin. The carotenoids in A. chinensis were similar to those in A. deliciosa but also contained esterified xanthophylls. Only trace amounts of chlorophyll were present in A. chinensis. The major carotenoid in both A. macrosperma and A. polygama was beta-carotene, with no chlorophyll detected. The yellow color of A. chinensis was mostly due to the reduction of chlorophyll rather than an increase in carotenoid concentration. In contrast to the three yellow/orange species, the green fruit of A. deliciosa retains chlorophyll during maturation and ripening, and esterified xanthophylls are not produced. This suggests that in fruit of A. deliciosa chloroplasts are not converted to chromoplasts as is typical for ripening fruit.     

朱红橘果实成熟过程中类胡萝卜素的积累及相关基因的表达分析

为探究朱橘类果实成熟过程中类胡萝卜素的积累及相关基因的表达模式,本研究以朱红橘为材料,使用手持色差仪测定果实成熟过程中果皮和果肉的色差值,利用液相色谱串联质谱(LC-MS/MS)检测类胡萝卜素组分的含量变化,并利用实时荧光定量PCR(qRT-PCR)分析类胡萝卜素代谢相关基因的表达.结果表明,朱红橘成熟过程中,果皮和果...     

Stay-green phenotype slows the carotenogenic process in Capsicum annuum (L.) fruits

Stay-green mutants have been very useful for elucidating the chlorophyll catabolism pathway in higher plants. In the present study the possible relationship between the retention/catabolism of chlorophylls and the carotenogenic process taking place in ripening Capsicum annuum (L.) fruits has been investigated. Phytylated, dephytylated and oxidized chlorophyll derivatives, and total and individual carotenoids were analyzed over the whole ripening period. In general terms, the biosynthesis of carotenoid pigments taking place during the ripening of C. annuum fruits is identical in both red and stay-green lines, so that the carotenogenic process is independent of the retention of chlorophylls. However, it has been found that the carotenogenesis is slowed in the stay-green lines. Therefore, although the catabolism of chlorophylls and biosynthesis of carotenoids seem to be separate processes, the fact that they are taking place in the chloroplast/chromoplast suggests that some kind of interaction between the two processes may occur at different levels. Plastids corresponding to the wild genotype (red color fruit phenotype) show high plastoglobuli density and thylakoids are almost absent, whereas in the case of stay-green phenotype, thylakoids and plastoglobuli coexist in the same plastid (chlorochromoplasts). The role of carotenoid pigments on the physiological mechanism for protecting the preserved thylakoid structures is discussed.     

Change in the carotenoid and antioxidant content of spice red pepper (paprika) as a function of ripening and some technological factors

A study was conducted to investigate the change in quality attributes of red pepper (paprika) (Capsicum annuum L. var. Km-622) as a function of ripening and some technological factors. Of quality attributes, carotenoids and bioantioxidants (ascorbic acid and tocopherols) have been studied. It was found that the dynamics of fruit ripening with regard to carotenoids and bioantioxidants was influenced to a considerable extent by weather conditions of the production season. A rainy and cool season yielded fruits with more beta-carotene but less diesters of red xanthophylls as compared to those produced in a relatively dry and warm season. The ripening stage at harvest was found to affect the quality of paprika. Harvest at unripe stages (color break or faint red) resulted in a high accumulation of dehydroascorbic acid in the overripe fruits, whereas de novo biosynthesis of carotenoids and tocopherols was partially retarded. Application of pre-drying centrifugation resulted in a marked loss of ascorbic acid, and as a consequence, carotenoid stability was impaired during the storage of ground paprika. Sugar caramelization caused dry pods and ground paprika to retain more pigments and tocopherol as compared to those from control or centrifuged red pepper samples. During the storage of ground paprika, color stability was improved by grinding the seeds with the pericarp.     

Pigments in avocado tissue and oil

Pigments are important contributors to the appearance and healthful properties of both avocado fruits and the oils extracted from these fruits. This study determined carotenoid and chlorophyll pigment concentrations in the skin and three sections of the flesh (outer dark green, middle pale green, and inner yellow flesh-nearest the seed) and anthocyanin concentrations in the skin of Hass avocado during ripening at 20 degrees C. Pigments were extracted from frozen tissue with acetone and measured using high-performance liquid chromatography. Pigments were also measured in the oil extracted from freeze-dried tissue sections by an accelerated solvent extraction system using hexane. Carotenoids and chlorophylls identified in the skin, flesh, and oil were lutein, alpha-carotene, beta-carotene, neoxanthin, violaxanthin, zeaxanthin, antheraxanthin, chlorophylls a and b, and pheophytins a and b with the highest concentrations of all pigments in the skin. Chlorophyllides a and b were identified in the skin and flesh tissues only. As the fruit ripened and softened, the skin changed from green to purple/black, corresponding to changes in skin hue angle, and a concomitant increase in cyanidin 3-O-glucoside and the loss of chlorophyllide a. In flesh tissue, chroma and lightness values decreased with ripening, with no changes in hue angle. The levels of carotenoids and chlorophylls did not change significantly during ripening. As fruit ripened, the total chlorophyll level in the oil from the flesh sections remained constant but declined in the oil extracted from the skin.     

Carotenoid profiling and biosynthetic gene expression in flesh and peel of wild-type and hp-1 tomato fruit under UV-B depletion

Although light is recognized as one of the main factors influencing fruit carotenogenesis, the specific role of UV-B radiation has been poorly investigated. The present work is addressed to assess the molecular events underlying carotenoid accumulation in presence or absence of ultraviolet-B (UV-B) light in tomato fruits of wild-type and high pigment-1 (hp-1), a mutant characterized by exaggerated photoresponsiveness and increased fruit pigmentation. Gene expression analyses indicated that in wild-type fruits UV-B radiation mainly negatively affects the carotenoid biosynthetic genes encoding enzymes downstream of lycopene both in flesh and peel, suggesting that the down-regulation of genes CrtL-b and CrtL-e and the subsequent accumulation of lycopene during tomato ripening are determined at least in part by UV-B light. In contrast to wild-type, UV-B depletion did not greatly affect carotenoid accumulation in hp-1 and generally determined minor differences in gene expression between control and UV-B-depleted conditions.     

Chlorophyll catabolism pathway in fruits of Capsicum annuum (L.): stay-green versus red fruits

The aim of the present study is to investigate the chlorophyll catabolism pathway of wild-type red and stay-green mutants of Capiscum annuum (L.) fruits. In the wild-type red lines chlorophyll catabolism is concomitant with the start of carotenogenesis, whereas in the stay-green mutant lines the chlorophylls coexist with that process, even in over-ripe fruit. During the first stages of ripening, the chlorophyll a/chlorophyll b ratio is similar for both genotypes, but as ripening proceeds, the ratio in the stay-green lines becomes very high as a result of a blocked degradation of chlorophyll a while chlorophyll b is degraded at a normal rate. The absence of dephytylated chlorophylls in the wild-type lines distinguishes these from the mutant lines, in which there is a sequential accumulation of chlorophyllide a and pheophorbide a. Allomerized chlorophylls (13(2)-OH-chlorophyll a and b) have also been identified in the catabolic process of the mutant lines, but are absent from the wild type. Consequently, an alteration in pheophorbide a oxygenase (PaO) activity seems to be responsible for the stay-green genotype in the lines of pepper analyzed in this study.     

Changes in chloroplast pigments of olive varieties during fruit ripening

Changes in chlorophyll and carotenoid pigments of five olive (Olea europaea L.) varieties destined for milling were investigated at six consecutive ripening stages. There was a manifest dependence between olive variety, moment of picking, and chloroplast pigment composition of the fruits. Although the content of chlorophylls and carotenoids differed with fruit variety, ripening always involved their gradual loss, which becames more pronounced with increased presence of anthocyanin compounds. The relative rates of disappearance of chlorophylls and carotenoids were markedly different between varieties, implying that the catabolism of these pigments takes place at a relative rate inherent to each variety. The varieties less rich in pigments showed the most extreme behavior. The highest relative rate of disappearance was observed in fruits of the Blanqueta variety, and the lowest was observed in those of Arbequina. The chlorophyll a/chlorophyll b ratio remained practically constant during ripening, with a value very similar for Hojiblanca, Picual, Cornicabra, and Blanqueta, but much higher for Arbequina, implying that the structure of the photosynthetic apparatus is different in the latter variety. In the five varieties studied, lutein was the slowest carotenoid to be degraded, so that its percentage in the fruits increased with ripening, whereas beta-carotene was the fastest to disappear. In ripe fruits covered with anthocyanins, chloroplast pigments were retained in both skin and pulp, with the rate of disappearance being much higher in the latter.     

Carotenoid accumulation and characterization of cDNAs encoding phytoene synthase and phytoene desaturase in garlic (Allium sativum)

Phytoene synthase (PSY) and phytoene desaturase (PDS), which catalyze the first and second steps of the carotenoid biosynthetic pathway, respectively, are key enzymes for the accumulation of carotenoids in many plants. We isolated 2 partial cDNAs encoding PSY (AsPSY-1 and AsPSY-2) and a partial cDNA encoding PDS (AsPDS) from Allium sativum. They shared high sequence identity and conserved motifs with other orthologous genes. Quantitative real-time PCR analysis was used to determine the expression levels of AsPSY1, AsPSY2, and AsPDS in the bulbils, scapes, leaves, stems, bulbs, and roots of garlic. High-performance liquid chromatography demonstrated that carotenoids were not biosynthesized in the underground organs (roots and bulbs), but were very abundant in the photosynthetic organs (leaves) of A. sativum. A significantly higher amount of β-carotene (73.44 μg·g(-1)) was detected in the leaves of A. sativum than in the other organs.     

Changes in sugars,acids, and volatiles during ripening of koubo [Cereus peruvianus (L.) Miller] fruits

The columnar cactus Cereus peruvianus (L.) Miller, Cactaceae (koubo), is grown commercially in Israel. The unripe fruits are green, and the color changes to violet and then to red when the fruit is fully ripe. The content of soluble sugars was found to increase 5-fold during ripening. Glucose and fructose were the main sugars accumulated in the fruit pulp, and each increased from 0.5 to 5.5 g/100 g fresh weight during ripening. The polysaccharides content decreased during ripening from 1.4 to 0.4 g/100 g fresh weight. The titratable acidity decreased and the pH increased during ripening. The major organic acid found in the fruit was malic acid, which decreased from 0.75 g/100 g fresh weight at the mature green stage to 0.355 g/100 g fresh weight in ripe fruits. Citric, succinic, and oxalic acids were found in concentrations lower than 0.07 g/100 g fresh weight. Prominent accumulation of aroma volatiles occurred toward the end of the ripening process. The main volatile found in the ripe fruit was linalool, reaching concentrations of 1.5-3.5 microg/g fresh weight.     

Edible coatings influence fruit ripening, quality, and aroma biosynthesis in mango fruit

The effects of different edible coatings on mango fruit ripening and ripe fruit quality parameters including color, firmness, soluble solids concentrations, total acidity, ascorbic acid, total carotenoids, fatty acids, and aroma volatiles were investigated. Hard mature green mango (Mangifera indica L. cv. Kensigton Pride) fruits were coated with aqueous mango carnauba (1:1 v/v), Semperfresh (0.6%), Aloe vera gel (1:1, v/v), or A. vera gel (100%). Untreated fruit served as the control. Following the coating, fruits were allowed to dry at room temperature and packed in soft-board trays to ripen at 21+/-1 degrees C and 55.2+/-11.1% relative humidity until the eating soft stage. Mango carnauba was effective in retarding fruit ripening, retaining fruit firmness, and improving fruit quality attributes including levels of fatty acids and aroma volatiles. Semperfresh and A. vera gel (1:1 or 100%) slightly delayed fruit ripening but reduced fruit aroma volatile development. A. vera gel coating did not exceed the commercial mango carnauba and Semperfresh in retarding fruit ripening and improving aroma volatile biosynthesis.     

黄杨叶色特性初步研究

通过对3个黄杨品种(大叶黄杨、金心黄杨、金边黄杨)的叶绿素、类胡萝卜素、花色苷进行测定和分析,认为金心黄杨和金边黄杨的黄色部分不是由类胡萝卜素的绝对含量增加或类胡萝卜素与叶绿素比值的提高形成的,而是由于黄色部分总色素特别是叶绿素含量降低而造成的。     

Unusual carotenogenesis in fruits with pronounced anthocyanic ripening (Olea europaea Var. Arbequina)

Fruits of the Olea europaea Arbequina variety showed a carotenogenic stage overlapping the biosynthesis of anthocyanins. At the start of ripening, the carotenoid concentration increases (20%) or is maintained (besides the esterification of xanthophylls found in this variety), compared with a decrease (30%) found in the same period in the Picual variety (used as a control that was representative of the rest of the varieties). Both the beta,beta and beta,epsilon carotenoid series were found to be implicated in this carotenogenic process. Differences in both varieties for the chlorophyll a/b ratio, chlorophylls/carotenoids ratio, and relative carotenoid composition may indicate the existence of a different metabolism of chloroplast pigments, but also indicates a different structure and function of the photosynthetic apparatus. This fact shows that the photosynthetic behavior in the Picual variety is similar to that of shaded leaves, and in the Arbequina variety is similar to that of sun leaves.     

Xanthophyll esterification accompanying carotenoid overaccumulation in chromoplast of Capsicum annuum ripening fruits is a constitutive process and useful for ripeness index

Changes in xanthophyll esterification degree during pepper fruit ripening have been studied in five cultivars (Numex, Mana, Belrubi, Delfin, and Negral). Esterification of xanthophylls with fatty acids is seen to be a process that is contemporary with and directly linked to the transformation of chloroplast (present in the green fruit) into chromoplast (present in the red fruit). Changes in the fractions of free and partially and totally esterified carotenoids are similar between varieties, reflecting the constitutive nature of esterification as part of the ripening process and being controlled by it. From the first stages of ripening, the fraction of totally esterified pigments (zeaxanthin diester, beta-cryptoxanthin diester, capsanthin diester, and capsorubin diester) makes up almost 50% of the total carotenoid content. The proportion of the partially esterified pigment fraction (zeaxanthin monoester, capsanthin monoester, and capsorubin monoester) in the total carotenoid content increases, with a gradual decrease in the fraction of free pigments (beta-cryptoxanthin, beta-carotene, zeaxanthin, capsanthin, and capsorubin). In the fully ripe stage, a balance is reached between the three esterification fractions (free, partially esterified, and totally esterified), with mean values of 24.17 +/- 4.06, 31.48 +/- 4. 61, and 44.36 +/- 5.05, respectively, which seems to be largely independent of variety. This suggests a marked control of the carotenoid composition of the totally developed chromoplast, indicating its use as an index of ripeness. The inclusion in the present study of a variety (Negral) that retains chlorophylls when ripening, and which shows the same esterification behavior, supports the idea that carotenogenesis is normal and independent of chlorophyll catabolism.     

Physicochemical conditions modulating the pigment profile in fresh fruit (Olea europaea Var. Gordal) and favoring interaction between oxidized chlorophylls and endogenous Cu

The changes in allomerized chlorophyll during the growth and development of the olive fruit as well as during the main operations of its processing as green table olive (alkaline treatment and lactic fermentation) were investigated to study their influence in the color alteration known as green staining (GS). Chlorophyll synthesis coincided in time with the maximum content in allomerized intermediates, weeks before the fruits were harvested for processing. The alkaline treatment caused a subsequent chlorophyll oxidation independent of the high or low initial content of allomerized chlorophylls. However, this oxidation was directly related with the oxidizing capacity of the alkaline solution and the cell deterioration caused. The later maintenance of the fruits in osmotic solutions at different pHs that reproduce the pH reduction caused by the lactic fermentation showed that at pH below 4.5 the insertion of Cu into the chlorophyll molecule was produced in certain fruits; the extent of this reaction was greatest when the prior formation of oxidized chlorophylls exceeded 23%. This apparent relationship between chlorophyll oxidation and copper chlorophyll complexes was investigated in table olives with GS alteration.     

桃PpNAC19的克隆及其对PpCCD4启动子活性的调节分析

为探究桃NAC基因对类胡萝卜素积累的调控作用,本研究从桃中克隆得到PpNAC19基因.序列分析表明,PpNAC19(XP_007223324.1)开放阅读框为867 bp,编码288个氨基酸,预测蛋白质分子量为33.2 kDa,平均疏水系数为-0.719,属于亲水性蛋白,含有一个典型的NAM结构域.亚细胞定位预测PpN...