Effects Of Eugenol Treatment On Chilling Injury And Expression Of CBF Transcription Factor In Green Eggplant Fruit During Cold Storage

Refrigeration is one of the most popular methods to mantain the quality of fruits and vegetables during postharvest.Eggplant fruit are cold-sensitive and very vulnerable to chilling injury during storage at low temperature.CBF is a type of transcription factors that plays an important role in inducing and increasing cold-resistance ability in plants.In this present studies,green eggplant(Solanum melongena L.)fruit cv.'chongming' were treated with different eugenol concentration(5,25 and 50 ?NL·L-1),and then stored at low temperature(4?),and the effects of eugenol treatments on fruit quality,proline metabolism and expression of SmCBF gene in relation to controlling chilling injury in green eggplant fruit were investigated during storage at 4?.The main results were asfollows:1.Eugenol treatment remarkably retarded the increase of CI index,weight loss and the activity of PPO,while promoted the accumulation of total phenolics and TSS.Eugenol treatment may act as a promising approach in enhancing chilling tolerance and maintaining quality of green eggplant.2.Eugenol treatment significantly promoted proline accumulation associated with increase in the activity of ?1-pyrroline-5-carboxylate synthetase(P5CS),ornithine aminotransferase(OAT)and inhibite in the activity of proline dehydrogenase(PDH).It was also found that eugenol treatment promoted the soluble sugar content and soluble protein content.These results suggested that the enhanced chilling tolerance induced by eugenol treatment may result from proline biosynthesis as well as some other osmotic regulation substances.3.The full length cDNA of CBF gene was cloned from green eggplant by RT-PCR and RACE(GenBank Accession was No.MG432696),named SmCBF.Bioinformatics analysis showed that the cDNA full-length of SmCBF gene was 1151 bp.The cloned cDNA contains an open reading frame(ORF)of 633 bp,which encodes a protein of 210 amino acid with a molecular mass of 23.6 kDa and a isoelectric point(pI)of 5.15.The sequence similarity of SmCBF gene with CBF gene in potato(Solanum tuberosum L.)was 74%.SmCBF sequence contains a highly conserved AP2 binding domain flanked by PKK/RPAGRxKFxETRHP and DSAWR characteristic sequences.4.To investigate the molecular regulation of chilling tolerance by eugenol treatment in green eggplant,a 1151-bp SmCBF gene were identified,and its expression in response to eugenol treatment was measured using RT-qPCR.The results showed that the expression of SmCBF in eugenol treatment was significantly higher than in control fruit during storage at 4?.These findings indicate that eugenol treatment can alleviate and delay CI in cold-stored green eggplant by inducing the expression of SmCBF.