Comparative transcriptomic analysis reveals the potential mechanism of hot water treatment alleviated-chilling injury in banana fruit.

Banana fruit is prone to chilling injury (CI) during cold storage, resulting in quality deterioration and commodity reduction. The hot water treatment (HWT), dipping banana fruit in hot water (52 °C) for 3 min, reduced CI symptom at 7 °C storage. The purpose of this study was to investigate the potential molecular mechanism of HWT on the alleviation of CI of postharvest banana fruit. It was found that HWT treatment obviously inhibited the increases in CI index, relative electrolytic leakage, and the contents of malonaldehyde (MDA) and O2•-, while enhanced proline accumulation. Further transcriptome analysis in the pericarp of banana fruit was evaluated during storage. The results showed that differentially expressed genes (DEGs) in the comparison between control and HWT group were mainly enriched in photosynthesis, chlorophyll metabolism, lipid metabolism, glutathione metabolism, and brassinosteroid and carotenoid biosynthesis. Moreover, transcriptome expression profiles and RT-qPCR analyses exhibited that the corresponding genes involved in these metabolism pathways and heat shock proteins (HSPs) were upregulated by HWT during cold storage. In general, our findings clearly reveal the potential pathways by which HWT alleviates CI in banana fruit, enriching the theoretical basis for the application of hot water to reduce CI in fruits.

Shikonin enhances sensitization of gefitinib against wild-type EGFR non-small cell lung cancer via inhibition PKM2/stat3/cyclinD1 signal pathway.

AIMS: Mutant EGFR Non-small cell lung cancer has benefit from gefitinib, but it has limited effect for wild-type EGFR tumors. Shikonin, a natural naphthoquinone isolated from a traditional Chinese medicine, the plant Lithospermum erythrorhizon (zicao), not only can inhibit the tumor growth, but also overcome cancer drug resistance. Our aim is to investigate whether shikonin can enhance antitumor effect of gefitinib in EGFR wild-type lung cancer cells in vitro and in vivo. MATERIALS AND METHODS: CCK-8 was used to determine the proliferation of EGFR wild-type non-small cell lung cancer. Apoptosis and cell cycle were detected by flow cytometry. PKM2, STAT3, p-STAT3 and cyclinD1 were detected by Western blot. A549 tumor model was established to observe the antitumor effect of shikonin combination with gefitinib in vivo. KEY FINDINGS: The results showed that combination of shikonin with gefitinib exhibited synergistic antitumor effect in vitro and in vivo. Its potential molecular mechanisms may be associated with inhibition of PKM2/STAT3/cyclinD1. SIGNIFICANCE: These results provide a promising therapeutic approach for the treatment of wild-type EGFR non-small cell lung cancer.

Molecular characterization and expression profiles of MaCOL1, a CONSTANS-like gene in banana fruit.

CONSTANS (CO) gene is a key transcription regulator that controls the long-day induction of flowering in Arabidopsis plant. However, CO gene involved in fruit ripening and stress responses is poorly understood. In the present study, a novel cDNA encoding CONSTANS-like gene, designated as MaCOL1 was isolated and characterized from banana fruit. The full length cDNA sequence was 1887bp with an open reading frame (ORF) of 1242bp, encoding 414 amino acids with a molecular weight of 46.20kDa and a theoretical isoelectric point of 5.40. Sequence alignment showed that MaCOL1 contained two B-box zinc finger motifs and a CCT domain. In addition, MaCOL1 showed transcriptional activity in yeast and was a nucleus-localized protein. Real-time PCR analysis showed that MaCOL1 was differentially expressed among various banana plant organs, with higher expression in flower. Expression of MaCOL1 in peel changed slightly, while accumulation of MaCOL1 transcripts in pulp obviously increased during natural or ethylene-induced fruit ripening, suggesting that MaCOL1 might be associated with the pulp ripening of banana fruit. Moreover, accumulation of MaCOL1 transcript was obviously enhanced by abiotic and biotic stresses, such as chilling and pathogen Colletotrichum musae infection. Taken together, our results suggest that MaCOL1 is a transcription activator and may be involved in fruit ripening and stress responses.

Expression of genes associated with ethylene-signalling pathway in harvested banana fruit in response to temperature and 1-MCP treatment.

BACKGROUND: Little attention has been paid to characterising the ethylene-signalling pathway genes in relation to abnormal ripening of harvested banana fruit during storage at high temperature. The aim of the present study was to investigate banana fruit abnormal ripening and the expression of ten genes associated with the ethylene-signalling pathway, namely MaACS1, MaACO1, MaERS1-4 and MaEIL1-4, at high temperature. Changes in these parameters of banana fruit at high temperature in response to 1-MCP pretreatment were also investigated. RESULTS: High temperature accelerated the decline in fruit firmness, increased ethylene production and inhibited degreening in banana fruit, resulting in fruit abnormal ripening. In addition, the expression of MaACS1, MaACO1, MaERS2, MaERS3, MaERS4, MaEIL1, MaEIL3 and MaEIL4 was enhanced in banana fruit stored at high temperature. However, application of 1-MCP prior to high temperature storage delayed fruit abnormal ripening and simultaneously suppressed the expression of MaACS1, MaERS2, MaERS3, MaEIL1, MaEIL3 and MaEIL4. CONCLUSION: The findings of this study suggested that the expression of genes associated with the ethylene-signalling pathway might be involved in banana fruit abnormal ripening at high temperature. Application of 1-MCP suppressed the expression of genes associated with the ethylene-signalling pathway, which may be attributed at least partially to 1-MCP delaying fruit abnormal ripening at high temperature.

Cloning of phospholipase D from grape berry and its expression under heat acclimation.

To investigate whether phospholipase D (PLD, EC 3.1.4.4) plays a role in adaptive response of post-harvest fruit to environment, a PLD gene was firstly cloned from grape berry (Vitis Vinifera L. cv. Chardonnay) using RT-PCR and 3'- and 5'-RACE. The deduced amino acid sequence (809 residues) showed 84.7% identity with that of PLD from Ricinus communis. The secondary structures of this protein showed the characteristic C2 domain and two active sites of a phospholipid-metabolizing enzyme. The PLD activity and its expression in response to heat acclimation were then assayed. The results indicated PLD was significantly activated at enzyme activity, as well as accumulation of PLD mRNA and synthesis of new PLD protein during the early of heat acclimation, primary suggesting that the grape berry PLD may be involved in the heat response in post-harvest grape berry. This work offers an important basis for further investigating the mechanism of post-harvest fruit adaptation to environmental stresses.