不同品种哈密瓜果实脯氨酸代谢对低温的响应  

Proline Metabolism of Different Varieties of Hami Melon Fruits in Response to Low Temperature

作　　者：毕莹 王新宇 李慧 黄帅 张琪 雷雅馨 王雪 王富鑫 许文昌 王静 BI Ying;WANG Xinyu;LI Hui;HUANG Shuai;ZHANG Qi;LEI Yaxin;WANG Xue;WANG Fuxin;XU Wenchang;WANG Jing(College of Food Science and Pharmacy,Xinjiang Agricultural University,Ürümqi 830052,China)

机构地区：[1]新疆农业大学食品科学与药学学院,新疆乌鲁木齐830052

出　　处：《食品科学》2024年第6期216-224,共9页Food Science

基　　金：国家自然科学基金地区科学基金项目(32260613);新疆维吾尔自治区自然科学基金面上项目(2022D01A80)。

摘　　要：为了探究两个品种哈密瓜果实在低温贮藏过程中脯氨酸代谢的变化,本实验以‘西周密25号’以及‘伽师瓜’哈密瓜为原料,经24 h预冷后放置在(3.0±0.5)℃的机械冷库中贮藏,每7 d取样一次,取6次,共计42 d。观察记录两个品种哈密瓜果实低温贮藏期间的冷害症状,测定冷害指数、游离脯氨酸含量及脯氨酸代谢相关指标。结果表明:‘伽师瓜’的冷害症状明显轻于‘西周密25号’,随着贮藏时间的延长,两个品种哈密瓜果实脯氨酸含量、Δ1-吡咯琳-5-羧酸合成酶(Δ1-pyrrolidine-5-carboxylicacidsynthase,P5CS)活性、鸟氨酸转氨酶(ornithine transaminase,OAT)活性及其基因相对表达量均明显升高,其中‘伽师瓜’贮藏期间以上指标总体显著高于‘西周密25号’,脯氨酸脱氢酶(proline dehydrogenase,ProDH)活性及其基因相对表达量降低,说明在两个品种哈密瓜果实受到低温胁迫时,均能通过提高脯氨酸含量以及脯氨酸合成关键酶P5CS、OAT活性,降低脯氨酸降解关键酶ProDH活性,抵御外界低温环境带来的伤害。经代谢组学研究发现,随着果实冷害加剧,‘西周密25号’果实的氨基酸含量下降,而‘伽师瓜’果实的氨基酸含量则呈上升趋势。此外,对哈密瓜果实脯氨酸代谢途径中的关键基因CmP5CS进行设计合成全基因序列,发现哈密瓜CmP5CS与甜瓜(LOC103485529)P5CS的亲缘性最近,表明哈密瓜CmP5CS基因在功能上与甜瓜类似。In order to investigate the change in proline metabolism of two varieties of Hami melon fruits during lowtemperature storage,‘Xizhoumi 25’and‘Gashi’melons were pre-cooled for 24 h and then placed for up to 42 days in a mechanical cold storage at(3.0±0.5)℃.Chilling injury symptoms were recorded,and chilling injury index,free proline content and proline metabolism-related indexes were measured every seven days.The results showed that the symptoms of chilling injury in‘Gashi’melon were significantly milder than those in‘Xizhoumi 25’melon,and as the storage time increased,free proline content,Δ1-pyrrolidine-5-carboxylic acid synthase(P5CS)activity,ornithine transaminase(OAT)activity and their relative gene expression increased significantly for both varieties;all these indicators were significantly higher in‘Gashi’melon than‘Xizhoumi 25’melon.The activity and relative gene expression of proline dehydrogenase(ProDH)decreased,indicating that both varieties of Hami melon fruits could resist chilling injury by increasing the free proline content and the activities of P5CS and OAT,the key enzymes for proline synthesis,and decreasing the activity of ProDH,the key enzyme for proline degradation.The metabolomics study revealed that the amino acid content of‘Xizhoumi 25’melon decreased when the chilling injury became more serious,while the amino acid content of‘Gashi’melon showed an opposite trend.Whole gene synthesis of CmP5CS,a key enzyme gene involved in the proline metabolic pathway of Hami melon fruits,revealed that the Hami melon CmP5CS gene had the closest relatedness to melon(LOC103485529)P5CS,indicating functional similarity between them.

关 键 词：哈密瓜果实 冷害 脯氨酸代谢 代谢组学 全基因合成 

分 类 号：TS255.3[轻工技术与工程—农产品加工及贮藏工程]