Jinhua Zuo

Deciphering the roles of circRNAs on chilling injury in tomato

Various circular RNAs (circRNAs) are newly identified in animals and plants through high-throughput deep sequencing which play important roles in miRNA function and transcriptional controlling. However, little is known regarding circRNAs in tomato fruit. In this study, we systematically parse the circRNAs in the whole genome using the combination methods of deep sequencing and bioinformatics. In all, 854 circRNAs were identified in our results, among them, 163 circRNAs exhibit chilling responsive expression. Intriguingly, several circRNAs were predicted to involved in chilling responsive process, such as redox reaction, cell wall degradation, Arginine and polyamine metabolism, heat and cold shock protein, energy metabolism, Jasmonic acid and abscisic acid metabolism, low temperature and salt responsive protein and low temperature-induced transcription factors(CBF and WRKY). Furthermore, 102 circRNAs were found to act as the corresponding 24 miRNAs sponges in tomato. These discoveries deciphered the unexpected complexity of the regulatory circRNAs and may open a window for understanding the functions of circRNAs in plants.

Inhibitory effect of chitosan on growth of the fungal phytopathogen, Sclerotinia sclerotiorum, and sclerotinia rot of carrot

The antifungal activity of chitosan on a common fungal phytopathogen, Sclerotinia sclerotiorum, and the control effect on sclerotinia rot of carrot were investigated. Mycelial growth and fungal biomass were strongly inhibited by chitosan. Using propidium iodide stain combined with fluorescent microscopy, the plasma membrane of chitosan-treated S. sclerotiorum mycelia was observed to be markedly damaged. Concomitantly, protein leakage and lipid peroxidation was also found to be significantly higher in chitosan-treated mycelia compared to the control. Chitosan provided an effective control of sclerotinia rot of carrot, with induction of activity of defense-related enzymes including polyphenoloxidase and peroxidase. These data suggest that the effects of chitosan on sclerotinia rot of carrot may be associated with the direct damage to the plasma membrane and lipid peroxidation of S. sclerotiorum, and the elicitation of defense response in carrot.

Effect of Se treatment on the volatile compounds in broccoli.

Broccoli contains high levels of bioactive compounds but deteriorates and senesces easily. In the present study, freshly harvested broccoli was treated with selenite and stored at two different temperatures. The effect of selenite treatment on sensory quality and postharvest physiology were analyzed. Volatile components were assessed by HS-SPME combined with GC-MS and EN. The metabolism of Se and S was also examined. Results indicated that Se treatment had a significant effect on maintaining the sensory quality, suppressing the respiration intensity and ethylene production, as well as increasing the content of Se and decreasing the content of S. In particular, significant differences in the composition of volatile compounds were present between control and Se-treated. The differences were mainly due to differences in alcohols and sulfide compounds. These results demonstrate that Se treatment can have a positive effect on maintaining quality and enhancing its sensory quality through the release of volatile compounds.

Salicylic acid alleviates postharvest chilling injury of sponge gourd (Luffa cylindrica)

Effect of salicylic acid (SA) on chilling injury (Cl) of sponge gourd during storage (9 days, 9°C) plus shelf life (2 days, 20°C) was evaluated in this study. SA treatment at the concentration of 1.5 mmol L−1 significantly reduced postharvest Cl of sponge gourds. Besides, the application of SA could effectively decrease the electrolyte leakage, reduce the accumulation of malondialdehyde (MDA) and total phenolics, enhance the activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX), and inhibit the activities of phenylalanine ammonia-lyase (PAL) and polyphenol oxidase (PPO). The beneficial effects of SA could be attributed to preserved membrane integrity, inhibited membrane peroxidation, enhanced antioxidant system and suppressed activities of browning related enzymes. In a sense, SA as a postharvest tool may be commercially used in alleviating Cl of sponge gourd.

Integrative analysis of long non-coding RNA acting as ceRNAs involved in chilling injury in tomato fruit

Long-non-coding RNA (LncRNA) is a kind of non-coding endogenous RNA that plays essential roles in diverse biological processes and various stress responses. To identify and elucidate the intricate regulatory roles of lncRNAs in chilling injury in tomato fruit, deep sequencing and bioinformatics methods were performed here. After strict screening, a total of 1411 lncRNAs were identified. Among these lncRNAs, 239 of them were significantly differentially expressed. A large amount of target genes were identified and many of them were found to code chilling stress related proteins, including redox reaction related enzyme, important enzymes about cell wall degradation, membrane lipid peroxidation related enzymes, heat and cold shock protein, energy metabolism related enzymes, salicylic acid and abscisic acid metabolism related genes. Interestingly, 41 lncRNAs were found to be the precursor of 33 miRNAs, and 186 lncRNAs were targets of 45 miRNAs. These lncRNAs targeted by miRNAs might be potential ceRNAs. Particularly, a sophisticated regulatory model including miRNAs, lncRNAs and their targets was set up. This model revealed that some miRNAs and lncRNAs may be involved in chilling injury, which provided a new perspective of lncRNAs role.

Analysis of long-non-coding RNAs associated with ethylene in tomato

Long-Non-Coding RNAs (LncRNAs) are a class of non-coding endogenous RNAs contributing to numerous biological processes. LeERF1 is a tomato ethylene response factor (ERF) near the end of the ethylene signal transduction pathway. To identify lncRNAs in tomato and elucidate their roles in ethylene signaling, deep sequencing was deployed in over-expression and repression LeERF1 transgenic and control tomato fruits. A total of 397 lncRNAs were identified, including 169 tomato lncRNAs that had not previously been identified. Among these, 12 were differentially expressed between the transgenic and control tomato fruits. Numerous lncRNA target genes were identified including many associated with ethylene signaling including auxin response factors and auxin-induced proteins, F-box proteins, ERFs and MADS-box proteins. In addition, two lncRNAs were found to be the precursor of three miRNAs and four lncRNAs could be targeted by five miRNAs. We propose a regulatory model highlighting the relationships between lncRNAs and their targets involved in ethylene signal transduction which establishes a foundation for addressing the role of LncRNAs in ethylene response.