干旱胁迫下中国沙棘脯氨酸含量变化及其关键调控基因的表达模式

Changes in Proline Content and Expression Patterns of Key Regulatory Genes in Sea Buckthorn(Hippophae rhamnoides subsp.sinensis) under Drought Stress

干旱胁迫严重影响植物的生长和产量,重度干旱胁迫会导致植物永久萎蔫。发掘中国沙棘的抗逆基因有助于提升植物抗旱性。脯氨酸是植物响应干旱胁迫的重要渗透调节物之一。为了探究中国沙棘中脯氨酸响应干旱胁迫的调节机制,本研究在干旱胁迫下,检测两年生中国沙棘扦插幼苗的叶片相对含水量和脯氨酸等5个抗旱相关生理指标;通过实时荧光定量PCR检测2个脯氨酸调控关键基因的表达量。结果表明,干旱胁迫下的中国沙棘叶片相对含水量逐渐下降;叶绿素、可溶性糖、可溶性蛋白和脯氨酸的含量呈上升趋势,且所有生理指标在复水后较处理前均下降;脯氨酸关键合成基因吡咯啉-5-羧酸合成酶(P5CS)基因在根、茎、叶中的相对表达量呈现先上升后下降的趋势,而调控脯氨酸分解的脯氨酸脱氢酶(ProDH)基因相对表达量迅速降低。本研究为揭示中国沙棘抗旱机理提供理论依据,同时为植物抗旱育种提供候选基因。

Drought stress is one of the a dverse environmental factors affecting plant growth and yield,severe drought stress cause plants to wilting permanently.Sea buckthorn has great potential in the study of stress resistance genes,due to its excellent cold and drought resistance.Proline is an important osmotic regulator in plants in response to drought stress.In order to explore the regulation mechanism of proline in sea buckthorn in response to drought stress,in this study,biennial sea buckthorn cuttings were used as experimental materials.Five drought-resistant physiological indicators were measured such as relative water content in leaves,content,etc.under drought stress;RT-qPCR was used to study the spatiotemporal expression patterns of two key regulatory genes of proline.The results showed that:under drought stress,the relative water content of sea buckthorn leaves decreased gradually and reached the lowest on the 10 th day of drought stress;The content of chlorophyll,soluble sugar,soluble protein,and proline generally increased,and all physiological indicators decreased after rehydration;Under drought stress,the relative expression of pyrrolline-5-carboxylic acid synthetase(P5 CS),a key proline synthetic gene,increased first and then decreased in roots,stems and leaves of sea buckthorn,the relative expression of proline dehydrogenase(ProDH),which regulates proline degradation,is rapidly down-regulated.This result can provide theoretical basis for revealing the drought resistance mechanism of sea buckthorn,and provide candidate genes for plant drought resistance breeding.