Jarukitt Limwachiranon

Involvement of energy metabolism to chilling tolerance induced by hydrogen sulfide in cold-stored banana fruit.

In this study, the effect of hydrogen sulfide (H2S) on energy metabolism in postharvest banana fruit under chilling stress was investigated. Banana fruit, fumigated with optimal concentration (0.5mM) of aqueous sodium hydrosulfide (NaHS) solution for 24h, were initially stored at 7°C for 14d and 20°C for another 6d. H2S treated banana fruit showed both higher value of firmness and Hue angle, as well as lower value of electrolyte leakage, malondialdehyde (MDA) content and ethylene production. These indicated slower development of chilling injury compared with the control. Decrease in adenosine triphosphate (ATP) and energy charge was not noticeable in H2S treated banana fruit. Moreover, the activity of H(+)-ATPase, Ca(2+)-ATPase, cytochrome C oxidase (CCO) and succinate dehydrogenase (SDH), associated with energy metabolism, were significantly enhanced by H2S treatment. Therefore, it can be deduced that H2S can potentially alleviate chilling development in banana fruit by increasing enzymes activities, involved in energy metabolism, to maintain energy charge.

Developmental and stress regulation on expression of a novel miRNA, Fan-miR73, and its target ABI5 in strawberry

Abscisic acid (ABA) is a critical plant hormone for fruit ripening and adaptive stress responses in strawberry. Previous high-throughput sequencing results indicated that ABA-insensitive (ABI)5, an important transcription factor in the ABA signaling pathway, was a target for a novel microRNA (miRNA), Fan-miR73. In the present study, exogenous ABA treatment was found to accelerate fruit ripening through differentially regulating the transcripts of ABA metabolism and signal transduction related genes, including NCED1, PYR1, ABI1, and SnRK2.2. Expression of Fan-miR73 was down-regulated in response to exogenous ABA treatment in a dosage-dependent manner, which resulted in an accumulation of ABI5 transcripts in the ripening-accelerated fruits. In addition, both UV-B radiation and salinity stress reduced the transcript levels of Fan-miR73, whereas promoted ABI5 expression. Furthermore, high negative correlations between the transcriptional abundance of Fan-miR73 and ABI5 were observed during ripening and in response to stress stimuli. These results enriched the possible regulatory role of miRNA involved in the post-transcriptional modification of ABI5 during strawberry ripening, as well as responses to environmental stresses.

Lotus Flavonoids and Phenolic Acids: Health Promotion and Safe Consumption Dosages: Lotus flavonoids and phenolic acids…

Nelumbo nucifera Gaertn., also known as the sacred lotus, is extensively cultivated in Southeast Asia, primarily for food and as an herbal medicine. This article reviews studies published between 1995 and 2017, on flavonoid and phenolic acid profiles and contents of 154 different cultivars of lotus. So far, some 12 phenolic acids and 89 to 90 flavonoids (47 flavonols, 25 to 26 flavons, 8 flavan-3-ols, 4 flavanons, and 5 anthocyanins) have been isolated from different parts of the lotus plant, including its leaves (whole leaf, leaf pulp, leaf vein, and leaf stalk), seeds (seedpod, epicarp, coat, kernel, and embryo), and flowers (stamen, petal, pistil, and stalk), although not all of them have been quantified. Factors affecting flavonoids and phenolic acid profiles, including types of tissues and extracting factors, are discussed in this review, in order to maximize the application of the lotus and its polyphenols in the food industry. Health promotion activities, attributed to the presence of flavonoids and phenolic acids, are described along with toxicology studies, illustrating appropriate usage and safe consumption dosages of lotus extracts. This review also presents the controversies and discusses the research gaps that limit our ability to obtain a thorough understanding of the bioactivities of lotus extracts.

Effect of Exogenous Nitro Oxide on Chilling Tolerance, Polyamine, Proline, and γ-Aminobutyric Acid in Bamboo Shoots (Phyllostachys praecox f. prevernalis)

The effects of exogenous nitro oxide (NO) on chilling resistance and the metabolism of polyamine, proline, and γ-aminobutyric acid of bamboo shoots were investigated. Bamboo shoots were dipped in 0.07 mM sodium nitroprusside (SNP) and stored at 1 °C for 56 days. During the storage, the development of chilling injury of SNP treated bamboo shoots was inhibited with decreased accumulation of malonaldehyde and electrical leakage. At the end of storage, the chilling injury incidence of treated bamboo shoots decreased by 37.9% while their malonaldehyde content and electrical leakage were 8.8% and 18.6% lower than that of the control, respectively. Interestingly, the endogenous NO, polyamines, γ-aminobutyric acid, and proline contents of treated bamboo shoot also significantly increased. Consistently, the metabolisms of these nitrogenous compounds were stimulated in treated bamboo shoots, according to their higher (20.2%-49.8%) related enzyme activities, including nitric oxide synthase, arginine decarboxylase, ornithine decarboxylase, glutamate decarboxylase, orn-δ-aminotransferase, and Δ1-pyrroline-5-carboxylate synthetase. The results indicated that the SNP treatment enhanced chilling tolerance of bamboo shoots, which might associate with the activated metabolism of polyamines, γ-aminobutyric acid, and proline. SNP treatment might be an alternative technology to avoid chill injury during cold storage of bamboo shoots.

Improvement of phenolic compounds extraction from high-starch lotus (Nelumbo nucifera G.) seed kernels using glycerol: New insights to amylose/amylopectin – Phenolic relationships

Lotus seed kernel (LSK) has high starch content and possesses many bioactivities, which are mainly attributed to its phenolics. In the present study, LSK phenolics were extracted using aqueous glycerol, and the obtained phenolics and its starch properties were observed for their correlations. Response surface methodology indicated significant quadratic effect of temperature and significant linear effect of glycerol on LSK phenolics (p < 0.05). Temperature also had a significant effect on LSK starch solubility and swelling power and % leaching amylose (p < 0.05). Leaching amylose in the presence of glycerol and swelling power showed positive correlations with LSK phenolics in a linear relationship (r = 0.825, p < 0.01) below 50 °C and a monotonic relationship (rs = 0.933, p < 0.01) above 60 °C, respectively. A building block backbone model was adopted to illustrate the interaction between amylose/amylopectin-glycerol, and most importantly, their relationship to LSK phenolics.

Effects of elevated CO 2 on energy metabolism and γ-aminobutyric acid shunt pathway in postharvest strawberry fruit

The elevated CO2 was applied to the strawberry fruit during storage at 0 °C, in which its effects on energy metabolism and the γ-aminobutyric acid (GABA) shunt pathway were investigated. 10% and 20% CO2 maintained quality of the fruit. The energy charge of 10% and 20% CO2-treated fruit was decreased by 7.58% and 23.93% on day 12, respectively, compared with the control fruit, which was associated with the decline of NADH/NAD+. The GABA in 10% and 20% CO2-treated fruit was increased by 1.2-fold and 1.6-fold compared with the control fruit on day 12, respectively. The accumulation of GABA resulted from the decrease of GABA transaminase activity and gene expression, which may partially contribute to the decrease of NADH at later storage. These results indicated that 20% CO2 is an optimal concentration for strawberry fruit to prolong the storage to 12 days.

Proteomic Studies on Fruit Ripening and Senescence

ABSTRACT Fruits containing beneficial nutrients are of significant economic importance. Due to the rapid development of “omic” technologies and strategies, the proteomic approach, in addition to genomics, transcriptomics, and metabolomics, has attracted the attention of scientists to cover the comprehensive analysis of plant physiology and biology. The implementation of quantitative proteomic approach contributed to elucidating the molecular mechanism underlying fruit development, senescence, physiological disorders, and response to exogenous treatments. During the last decade, the isotope-labeled/label-free proteomic strategies have been applied in fruit science to obtain the near-complete investigations of quantifications and functions of fruit proteomes. Additionally, the recent implementation of mass spectrometry (MS)-based selected/multiple reaction monitoring (SRM/MRM) technology in targeted proteomics introduced the possibility of quantitative follow-up of specific protein targets in hypothesis-driven experiments. This review presents a comprehensive and up-dated overview of the application of proteomics in fruit ripening and development, fruit senescence, fruit physiological disorders, and oxidative stress, as well as the fruit proteomic response to postharvest exogenous treatment. The proteomic technologies and strategies in fruit science are summarized, and the panoramic views of differentially expressed proteins are discussed.