摘要
【目的】探究不同O_(2)体积分数的自发气调(modified atmosphere,MA)处理对桃果实贮藏冷害及风味品质的影响,分析PDC和ADH基因在MA处理诱导乙醇和乙醛积累中的作用,确定桃果实MA处理的适宜O_(2)体积分数。【方法】以湖景蜜露和中华寿桃果实为材料,分别在0℃冷藏40、60 d后转至20℃货架放置3、4 d;设置3种MA处理,即MA1、MA2和MA3,其冷藏中后期O_(2)体积分数控制在1.0%、3.0%和5.0%,以直接冷库贮藏为对照。测定冷害相关生理指标、乙醛和乙醇含量及PpPDCs和PpADHs基因表达量。【结果】3种MA处理均可有效抑制桃果实冷害,在货架期结束,湖景蜜露和中华寿桃对照组的褐变指数分别高达0.53和0.69,而MA处理的果实褐变指数均低于0.1。MA1和MA2处理的果实在贮藏期间乙醇和乙醛不同程度积累,而MA3处理对乙醇和乙醛积累无明显影响。转货架后各处理乙醇积累有所减少而乙醛变化不大。在桃基因组中共鉴定出5个PpPDCs和33个PpADHs基因家族成员,其中,PpPDC1、PpPDC2、PpADH1、PpADH2和PpADH3基因在转录组中的表达量较高。不同MA处理下PpPDCs和PpADHs基因的表达模式存在较大差异,MA1处理的表达量普遍最高,而MA3处理则普遍较低;相关性分析表明PpPDC2和PpADH1基因表达与乙醇和乙醛含量呈现显著正相关。【结论】3种最终O_(2)体积分数为1%~5%的MA处理均可有效减轻桃果实冷害,但MA1和MA2处理不同程度地导致乙醇和乙醛积累,PpADH1和PpPDC2基因在此过程中发挥重要作用;MA3处理对PpPDCs和PpADHs基因表达的影响较小,果实乙醇和乙醛积累及异味程度总体而言与对照相近;5%为湖景蜜露和中华寿桃MA的适宜O_(2)体积分数。
【Objective】Peach fruit is perishable and easy to deteriorate at room temperature,and cold storage is an effective way to prolong storage life.Peach fruit is chilling-sensitive,and the loss of fruit quality after postharvest cold storage caused by chilling injury(CI)reduces consumer satisfaction.Modified atmosphere(MA)has been extensively used to alleviate chilling injury(CI)of horticultural produces.However,in some cases,the flavor quality decreases due to excessive deficiency in oxygen and accumulation of carbon dioxide in MA containers.In peach,the effects of MA treatment on fruit flavor quality suffering from CI remain largely unknown.In this study,Hujingmilu and Zhonghuashoutao peach fruits were used as materials to explore the effects of MA treatments with different O_(2) concentrations,on chilling injury and flavor quality of peach fruit during storage.Meanwhile,through analyzing the correlation between the gene expression of ADH and PDC,and accumulation of acetaldehyde and ethanol,the study aimed to identify the critical members involved.Finally,the study was carried out to determine the most suitable O_(2) concentration for MA storage of peach fruits.【Methods】The peach fruits were pre-cooled at 0℃for 12 hours to dissipate the field heat,and then divided into four groups,with final O_(2) concentrations controlled at 1%,3%,5%and non-control for MA1,MA2,MA3 and control,respectively.Hujingmilu and Zhonghuashoutao fruits were stored at 0℃for 40 d and 60 d,and then put on 20℃shelf for 3 d and 4 d,respectively.Firmness,ethylene production,internal browning(IB)index,contents of soluble sugars,organic acids,ethanol and acetaldehyde were measured.The ADH and PDC gene families were analyzed in silico,and the expression of main expressed members PpPDC1 and PpPDC2 as well as PpADH1,PpADH2 and PpADH3 was determined by RT-qPCR.The relationship between gene expression of PpPDCs and PpADHs,and contents of acetaldehyde and ethanol were analyzed.【Results】Hujingmilu and Zhonghuashoutao peach fruits suffered from serious IB on shelf following cold storage,with index as high as 0.53 and 0.69,respectively.All three MA treatments effectively inhibited the IB of both cultivars,with indexes all below 0.1.With Hujingmilu,the MA treatment also effectively alleviated the impairment of cold storage on fruit softening.With Zhonghuashoutao,the ethylene production of the fruits with MA1 and MA3 treatments was significantly higher than that of control,indicating that MAtreatment guaranteed the normal ripening of the fruit.The ethanol and acetaldehyde contents,however,varied greatly among different treatments.Compared with control,ethanol and acetaldehyde significantly accumulated in fruits of MA1 and MA2,while there was no marked difference in fruits treated with MA3 or control.During the shelf life,the accumulation of ethanol in all treatments was reduced,while for acetaldehyde,no significant change was observed.A total of 5 PpPDCs and 33 PpADHs were identified from genome database of peach.PpPDC1 and PpPDC2,as well as PpADH1,PpADH2 and PpADH3 were identified as highly expressed members and hence used for further analysis.The expression patterns of PpPDCs and PpADHs in the postharvest storage of peach fruits were differential between fruits at cold storage and those on shelf.For example,the expression of PpADH1 during cold storage was significantly higher than that on shelf,with maximum difference being up to 17.19 times,while PpADH2 and PpADH3 showed opposite trends.The expression of PpPDCs during cold storage was generally higher than that on shelf.The expression patterns of PpPDCs and PpADHs were also quite different under MA treatments with different O_(2) concentrations.Overall,the expression of PpPDCs and PpADHs in fruits of MA1 was highest,while that in fruit of MA3 was lower.At the end of the cold storage period of Hujingmilu and Zhonghuashoutao(40 d and 60 d),the expression level of PpADH1 in fruit of MA3 was only 15.48%and 43.24%of MA1,and for PpPDC2,only 15.11%and 66.93%in two cultivars,respectively.Correlation analysis showed that the expression of PpPDC2 and PpADH1 were significantly and positively correlated with the accumulation of ethanol and acetaldehyde.【Conclusion】Compared with control,all MA treatments,with final O_(2) concentrations ranging from 1%to 5%,can effectively alleviate chilling injury.MA1 and MA2 treatments led to significant accumulation of ethanol and acetaldehyde,while MA3 did not.Among the 5 PpPDCs and 33 PpADHs,PpADH1 and PpPDC2 played important roles in accumulation of acetaldehyde and ethanol during postharvest storage of peach fruit.MA3 treatment inhibited the expression of PpPDCs and PpADHs,and prevented the excessive accumulation of ethanol and acetaldehyde.The MA treatment for peach was optimal with final O_(2) concentration controlled at 5%.
作者
徐思朦
艾少杰
薛蕾
朱长青
周楷轩
冷鹏
徐昌杰
XU Simeng;AI Shaojie;XUE Lei;ZHU Changqing;ZHOU Kaixuan;LENG Peng;XU Changjie(Department of Horticulture,College of Agriculture and Biotechnology,Zhejiang University,Hangzhou 310058,Zhejiang,China;Linyi Academy of Agricultural Science,Linyi 276012,Shandong,China)
出处
《果树学报》
CAS
CSCD
北大核心
2023年第9期1952-1965,共14页
Journal of Fruit Science
基金
国家重点研发计划项目(2022YFD2100103)
浙大山东农研院服务地方经济发展项目(ZDNY-2021-FWLY01008)
山东省农业重大应用技术创新项目。
关键词
桃
自发气调
O_(2)体积分数
冷害
乙醛
乙醇
PDC
ADH
Peach
Modified atmosphere(MA)
O_(2) concentration
Chilling injury
Acetaldehyde
Ethanol
PDC
ADH
