摘要
为探明外源脯氨酸对盐胁迫下甜瓜脯氨酸代谢的影响,以甜瓜品种‘雪美’为材料采用营养液栽培,对盐胁迫(100mmol·L-1 NaCl)、盐胁迫下添加外源脯氨酸(100mmol·L-1 NaCl+0.2mmol·L-1 Proline)以及对照3种处理后甜瓜幼苗叶片脯氨酸(Pro)含量、吡咯啉-5-羧酸合成酶(P5CS)、鸟氨酸转氨酶(OAT)和脯氨酸脱氢酶(ProDH)活性进行测定,并对OAT和ProDH基因进行克隆及半定量表达分析。结果显示:与对照相比较,盐胁迫条件下甜瓜幼苗叶片内Pro含量显著增加,P5CS活性增幅大于OAT活性,OAT基因表达量大部分时段内没有增加,ProDH活性下降,ProDH基因表达量减少;盐胁迫下添加外源脯氨酸进一步使幼苗叶片内Pro含量增加、OAT、ProDH活性提高、P5CS活性降低,并且使OAT基因表达量迅速增加、ProDH基因表达量先增加后回落。研究表明,盐胁迫条件下,甜瓜幼苗体内脯氨酸积累主要是通过增强脯氨酸的谷氨酸合成途径和抑制脯氨酸降解来实现;适量外源脯氨酸可以增强盐胁迫幼苗脯氨酸的鸟氨酸合成途径,但对谷氨酸合成途径有一定的抑制作用;通过调节合成和降解2种代谢途径进一步提高了脯氨酸含量,从而增强甜瓜幼苗耐盐胁迫能力。
The melon（Cucumis melo L.）variety ‘Xuemei＇was nutrient solution cultured to investigate the effect of exogenous proline on proline metabolism under salt stress.The content of proline,△1-pyrroline-5-carboxylate synthase（P5CS）enzyme activity,ornithine-oxo-acid transaminase（OAT）enzyme activity,proline dehydrogenase（ProDH）enzyme activity in leaves were measured under salt stress,addition of exogenous proline under salt stress and the controlrespectively,cloning and semi-quantitative expression analysis of OATand ProDH gene were also undertaken.The results showed that compared with the control,the content of proline in the leaves of the seedlings increased significantly under salt stress.The increase of P5 CS enzyme activity was larger than that of OAT enzyme,the amount of OATgene expression did not increase in the majority of time period.ProDH enzyme activity decreased and the amount of ProDH gene expression also decreased in the leaves of melon seedling under salt stress.With the addition of exogenousproline under salt stress.The content of proline further increased,the activities of OAT and ProDH enzyme improved and activity of P5 CS enzyme decreased,the amount of OATexpression increased rapidly,the amount of ProDHexpression increased at first and then fell.This result suggested that proline accumulationin the melon seedlings was mainly through the increase of glutamate pathway and inhibition of proline degradation under salt stress.The adequate exogenous proline under salt stress could enhance the ornithine pathway but had a certain inhibitory effect on the glutamate pathway,and proline was further accumulated to enhance salt tolerance of melon seedling by regulating the synthesis and degradation,two kinds of metabolism ways.
出处
《西北植物学报》
CAS
CSCD
北大核心
2015年第10期2035-2041,共7页
Acta Botanica Boreali-Occidentalia Sinica
基金
江苏省自然科学基金(BK20131243)
江苏省农业三新工程(SXGC[2015]311)
青蓝工程(苏教师[2014]23)
关键词
脯氨酸
盐胁迫
甜瓜
谷氨酸途径
鸟氨酸途径
proline
salt stress
Cucumis melo L
glutamate pathway
ornithine pathway
