摘要
以小桐子幼苗为材料,设置盐胁迫(200mmol·L-1 NaCl)和外源水杨酸处理(0~2.0mmol·L-1 SA)水培试验,通过检测幼苗叶片脯氨酸含量、脯氨酸代谢关键酶活性及相关代谢酶基因的表达水平,研究了外源水杨酸对盐胁迫下小桐子幼苗脯氨酸代谢机理的影响。结果显示:(1)外源0.9mmol·L-1 SA处理可显著提高盐胁迫下小桐子幼苗的脯氨酸含量,上调脯氨酸合成关键酶Δ1-吡咯琳-5-羧酸合成酶(P5CS)和鸟氨酸转氨酶(OAT)活性,以及上调JcP5CS和JcOAT基因的表达水平。(2)SA也显著抑制了脯氨酸降解酶ProDH的活性及JcProDH基因的表达水平。(3)SA处理还显著提高了盐胁迫下小桐子幼苗的组织活力,降低了叶片电解质渗漏率和丙二醛(MDA)含量。研究发现,外源SA可通过活化脯氨酸合成的谷氨酸途径和鸟氨酸途径,以及抑制脯氨酸的降解途径来促进盐胁迫下小桐子幼苗脯氨酸的积累;外源SA处理也可提高小桐子幼苗的耐盐性,且这种提高可能与SA诱导脯氨酸的积累密切相关。
Hydroponic experiments were carried out to study the effects of exogenous salicylic acid（SA,0-2.0 mmol·L^-1）on the metabolic mechanism of proline in Jatropha curcas seedlings under salt stress（200 mmol·L^-1 NaCl）.Seedlings of J.curcas under salt stress were treated with SA,and the content of proline,the activities of the key enzymes of proline metabolism as well as the expression of proline metabolism-related genes in leaves of J.curcas seedlings were measured.The results showed that：（1）the exogenous SA（0.9 mmol·L^-1）treatment led to a significant accumulation of proline in J.curcas seedlings under salt stress.It also induced almost immediate and rapid increase of activities of the key enzymesΔ1-pyrroline-5-carboxylate synthetase（P5 CS）and ornithine aminotransferase（OAT）of proline biosynthesis,and up-regulated JcP5 CSand JcOATexpression.（2）SA decreased the activity of proline dehydrogenase（ProDH）,a key enzyme of proline degradation,and inhibited JcProDH expression.（3）The SA treatment also increased tissue vitality,decreased the content of the lipid peroxidation product malondialdehyde（MDA）,and alleviated electrolyte leakage in J.curcas seedlings under salt stress.These results showed that the SA-induced proline accumulation in the J.curcas seedlings under salt stress might be a combined result of the activation of glutamate and ornithine pathways of proline biosynthesis and the simultaneous inhibition of the proline degradation pathway.In addition,exogenous SA treatment can enhance salt tolerance in J.curcas seedlings,and proline might be a key factor in this increased salt tolerance.
作者
杨婷
孔春燕
杨利云
龚明
杨双龙
YANG Ting;KONG Chunyan;YANG Liyun;GONG Ming;YANG Shuanglong(Key Laboratory of Biomass Energy and Environmental Biotechnology of Yunnan Province,Engineering Research Center of Sustainable Development and Utilization of Biomass Energy of Ministry of Education,School of Life Sciences,Yunnan Normal University,Kunming 65050)
出处
《西北植物学报》
CAS
CSCD
北大核心
2018年第6期1080-1087,共8页
Acta Botanica Boreali-Occidentalia Sinica
基金
国家自然科学基金(31260169,31460059)
关键词
小桐子
盐胁迫
水杨酸
脯氨酸
代谢途径
Jatropha curcas
salt stress
salicylic acid
proline
metabolic pathways
