Characteristics of Pollen Grains of Different Date Pollinator Cultivars and Their Metaxenia Effect on Secondary Metabolites, Enzymes and Other Biochemical Compounds of ‘piarom’ Dates at Different Stages of Fruit Growth

In this study, the characteristics of pollens of eight date pollinating cultivars including ‘Shahani’, ‘Zahedi’, ‘Beraem’, ‘Faryab’, ‘Sheikhali’, ‘Fard’ and ‘Jarvis’ were compared and their metaxenia effects on secondary metabolites, enzymes and other biochemical compounds of ‘Piarom’ date fruit was investigated in four stages of fruit growth and development. The pollens of these eight pollinating cultivars were compared in terms of carbohydrate, protein starch, total phenol, flavonoids, pectin methyl esterase, and amylase enzymes. According to the results, , pollens of ‘Sheikhali’, ‘Fard’, ‘Zahedi’ and ‘Shahani’ cultivars had higher amounts of the above compounds than other cultivars. Regarding the effect of pollens on the composition of ‘Piarom’ date fruit, ‘Fard’ and ‘Sheikhali’ pollens produced the lowest amount of soluable tannin, which resulted in better quality of ‘Piarom’ date fruits. Pollens of ‘Sheikhali’ and ‘Fard’ cultivars produced the highest amounts of glucose and fructose in the fruit. In relation to sucrose, ‘Jarvis’ and ‘Shikhali’ were the best. Pollens of ‘Sheikhali’ and ‘Fard’ cultivars caused the lowest amount of chlorophyll in different stages of fruit growth, indicating better decomposition of fruit chlorophyll and, as a result, better fruit quality. Pollens of ‘Sheikhali’ and ‘Fard’ cultivars produced the highest amount of secondary metabolites such as total phenol, carotenoids and anthocyanin at different stages of ‘Piarom’ date fruit development. Pollens of ‘Fard’ and ‘Sheikhali’ cultivars produced the highest levels of polygalacturonase, cellulase and invertase enzymes at different stages of ‘Piarom’ date fruit growth. Regarding cellulase enzyme, ‘Zahedi’ cultivar produced more ‘cellulase’ in fruit than ‘Sheikhali’. In general, the pollens of ‘Fard’ and ‘Sheikhali, in comparison with other cultivars, improved the quantity and quality of ‘Piarom’ date fruit, due to their metaxenia properties.

Pathophysiology of Fusarium oxysporum f. Sp. Dianthi in carnation (Dianthus caryophyllus L.)

The bio-chemical changes occurred in the carnation after inoculation with F. oxysporum f.sp. dianthi was studied under in vitro. Carnation plants inoculated with fourteen isolates of F.oxysporum f.sp.dianthi and monitored for their ability to production of fungal pectin-degrading enzymes viz., Pectin Methyl Esterase (PME), Polygalacturonase (PG) and Pectin Trans Eliminase (PTE) involved in development of disease symptoms. Production of pectinolytic enzymes in carnation plants were assessed from 2 days up to 8 days after inoculation at 48h intervals. The accumulation of these enzymes increased in two days after inoculation and attained a peak at six days after inoculation and slowly declined thereafter in all the inoculated plants. Among the fourteen isolates, YRPFOD2 had maximum ability to increase the activity of pectinolytic enzymes viz., Pectin Methyl Esterase (0.49 μ mole hydrogen ion / min / ml), Polygalacturonase (16.11% reduction in viscosity) and Pectin Trans Eliminase (57.59 % reduction in viscosity) after six days of inoculation in infected plants.

Allergen homologues, pathogenesis-related 1, polygalacturonase, and pectin methyl esterase from Japanese hop

Background: Japanese hop is an important cause of weed pollinosis in East Asia. Its pollen is abundant in autumn. This pollen is known to be the cause of many allergic diseases. However, molecular characteristics of its allergens have not been elucidated. Objective: In this study, we produced recombinant proteins of allergen homologues from Japanese hop by the analysis of expressed sequence tags (EST), and evaluated its allergenicity. Methods: cDNA library was constructed using as little as 50 ng of total RNA from Japanese hop pollen. Allergen homologues were identified by the initial screening of 963 EST clones. Recombinant proteins were overexpressed in the E. coli expression system and purified using Ni-nitrilotriacetic acid-agarose. Purified proteins were analyzed by ELISA. Results: Japanese hop pathogenesis-related 1 protein (PR-1) shares 37.0 to 44.4% of amino acid sequence identity with Art v 2, Cuc m 3, and Cyn d 24. Pectin methyl esterase (PME) shows 23.2 to 50.2% of identities to Act d 7, Ole e 11, and Sal k 1. Polygalacturonase (PGs) shows 16.7 to 19.3% of identities to Phl p 13, Cry j 2, Cha o 2, Jun a 2, Pla a 2, and Pla or 2. IgE antibodies from Japanese hop allergy patients’ sera recognized PR-1 (3.4%), PME (13.8%), PGs (3.7%), and profilin (13.8%), respectively. Conclusion: Novel allergenic components were identified, even though low IgE reactivity was displayed reflecting the low degree of cross-reactivity with other pollen allergens. We believe that these molecules have worth further studies.

Post-harvest behavior of green peppers after pectin methyl esterase and calcium chloride application

The green pepper (Capsicum annuum L.) is an important Brazilian vegetable and it is very much appreciated, besides being a source of vitamins, minerals and fibers. However, it has serious post-harvest shelf-life problems, such as tissue softening. The exogenous application of pectin methyl esterase and calcium has been shown to be efficient in maintaining the firmness of several fruits. Thus, the present study had as objective to evaluate the effects of the application of exogenous pectin methyl esterase (PME) and calcium in post-harvest conservation of the cv. Yolo Wander. For this, the green peppers were submitted to vacuum infusion with water, vacuum infusion with 7% of calcium chloride and vacuum infusion of PME associated to 7% calcium chloride, fruits without infusion were used as control. Loss of fresh mass, fruit firmness, peel color, soluble solids content, pH, total acidity and PME activity were evaluated. In relation to the loss of fresh mass there was a significant increase over time in all treatments. Also, according to the results, the fruits not immersed or those immersed in calcium chloride showed greater maintenance of the firmness, as well as smaller variations in the activity of the SME and low levels of organic acids. The vacuum infusion with 7% calcium chloride maintained the firmness and the physicochemical characteristics of the green pepper. However, the application of PME + CaCl2 did not promote the maintaining desirable firmness characteristics for the green pepper.

Overview of the Role of Cell Wall DUF642 Proteins in Plant Development

The DUF642 protein family is found exclusively in spermatophytes and is represented by 10 genes in Arabidopsis and in most of the 24 plant species analyzed to date. Even though the primary structure of DUF642 proteins is highly conserved in different spermatophyte species, studies of their expression patterns in Arabidopsis have shown that the spatial-temporal expression pattern for each gene is specific and consistent with the phenotypes of the mutant plants studied so far. Additionally, the regulation of DUF642 gene expression by hormones and environmental stimuli was specific for each gene, showing both up- and down-regulation depending of the analyzed tissue and the intensity or duration of the stimuli. These expression patterns suggest that the DUF642 genes are involved throughout the development and growth of plants. In general, changes in the expression patterns of DUF642 genes can be related to changes in pectin methyl esterase activity and/or to changes in the degree of methyl-esterified homogalacturonans during plant development in different cell types. Thus, the regulation of pectin methyl esterases mediated by DUF642 genes could contribute to the regulation of the cell wall properties during plant growth.