病毒诱导的精氨琥珀酸合成酶基因沉默对棉花氮代谢的影响

以棉花为研究对象,利用转录后基因沉默技术(VIGS)将棉花精氨琥珀酸合成酶(GhASS1)基因沉默,研究沉默后植物的氨基酸、多胺、一氧化氮(NO)等含氮化合物的代谢变化。结果表明:盐胁迫可以诱导棉花精氨琥珀酸合成酶(GhASS1)瞬时上调表达,GhASS1沉默严重影响氨基酸的合成,除天门冬氨酰(Ans)外,其他蛋白质组成型氨基酸质量分数显著降低,NO质量摩尔浓度和多胺(PAs)质量分数下降,棉花植株生长发育迟缓。GhASS1沉默对棉花精氨酸脱羧酶基因(GhADC)、棉花鸟氨酸脱羧酶基因(GhODC)表现出强烈的抑制作用,进而影响植物多胺的代谢和耐盐能力。高浓度盐环境下,沉默体系精氨酸(Arg)和NO质量摩尔浓度上升,GhARG1表达上调。GhASS1沉默对于植物是致命的,GhASS1是尿素循环和氨基酸代谢的关键环节,GhASS1沉默使GhARG1、GhADC和GhODC表达下调,严重影响整个氨基酸代谢,NO质量摩尔浓度,腐胺(Put)和精胺(Spm)质量分数显著降低,N代谢受阻,植株发育不良,生长迟滞,棉花中存在Arg-NO通路。

Effects of Virus-induced Gene Silencing(VIGS)of Argininosuccinate Synthase Gene on Cotton Nitrogen Metabolism

With cotton,we studied the metabolic changes of amino acids,polyamines,nitric oxide,and other nitrogen compounds in plants after silencing the gene of argininosuccinate synthase(GhASS1)using virus-induced gene silencing(VIGS).Salt stress could induce GhASS1 transient expression.GhASS1 silencing seriously affected the synthesis of amino acids.In addition to Asn,the contents of other protein constituent amino acids were significantly reduced.Nitric oxide(NO)and polyamines contents decreased,thereby resulting in the slow growth and development of the cotton plant.GhASS1 silencing showed a strong inhibitory effect on GhADC and GhODC,which affected the metabolism of polyamines and salt tolerance.In an environment with high salt concentration,the expression of GhARG1 was up-regulated,Arg and NO increased in the silencing system.GhASS1 silencing is critical to the plant.GhASS1 is the key pathway of the urea cycle and amino acid metabolism.GhASS1 silencing reduces the expressions of GhARG1,GhADC,and GhODC,thereby seriously affecting the metabolism of whole amino acids.NO,putrescine and spermidine were significantly decreased.The nitrogen-resistant obstructed plants developed dysplasia and growth retardation.Arg-NO pathway was detected in cotton.