紫花苜蓿对低磷酸盐和亚磷酸盐胁迫响应机制的比较分析  

Comparison of the Mechanism Differences of Alfalfa Response to Phosphate Deficiency and Phosphite Stress

作　　者：胡警匀 栗振义 王吉祥 杨国锋[1] 刘洪庆[1] 苗福泓[1] 杨超 唐伟 孙娟[1] HU Jing-yun;LI Zhen-yi;WANG Ji-xiang;YANG Guo-feng;LIU Hong-qing;MIAO Hong-fu;YANG Chao;TANG Wei;SUN Juan(College of Grassland Science of Qingdao Agricultural University,Qingdao 266109,China)

机构地区：[1]青岛农业大学草业学院,山东青岛266109

出　　处：《中国草地学报》2021年第8期26-33,共8页Chinese Journal of Grassland

基　　金：国家牧草产业技术体系(CARS-34);山东省一流学科-草学(1619002);山东省现代农业技术体系创新团队(SDAIT-23-01,SDAIT-23-08);青岛农业大学高层次人才启动基金(6631119038,6631120005);山东省自然科学基金青年项目(ZR2020QC185)资助。

摘　　要：为了阐明紫花苜蓿对低磷酸盐和亚磷酸盐胁迫响应机制的差异,采用正磷酸盐(正磷,0.5mmol/L KH_(2)PO_(4))、低磷酸盐(低磷,5μmol/L KH_(2)PO_(4))和亚磷酸盐(亚磷,0.5mmol/L KH_(2)PO3)分别处理苜蓿幼苗,分析不同磷酸盐处理下4、8和12d时苜蓿的形态、生理指标和磷吸收相关基因表达情况。结果显示,与对照相比,亚磷酸盐和低磷酸盐处理下植株地上部生物量在第8d时分别下降了52%和38%,在第12d时分别下降了44%和16%;亚磷酸盐胁迫12d时植株根部全磷含量上升了34%,而低磷处理12d时植株根部全磷含量下降达68%。实时荧光定量结果显示,低磷处理第4d时,MsPHO1基因受诱导,促进植物体内磷的转运及低磷应激反应;在第12d时MsSQD2表达上调,植物通过降解磷脂膜来调控体内磷平衡;低磷酸盐和亚磷酸盐处理都可诱导MsPHT2基因的表达,促进植物从外界吸收更多的磷。综上所述,低磷酸盐和亚磷酸盐胁迫均会抑制苜蓿地上部和地下部生长,但亚磷酸盐对苜蓿地上部的抑制程度大于低磷酸盐,且根部对亚磷酸盐吸收效率较大。因此,紫花苜蓿会通过抑制植株生长、增加根部对磷的吸收、调节低磷应激基因等适应亚磷酸盐环境。This study aimed to explore the differences of mechanisms underlying alfalfa response to phosphorus deficiency and phosphite stress.Alfalfa seedlings were treated with orthophosphate(0.5mmol/L KH_(2)PO_(4)),low level of phosphate(5μmol/L KH_(2)PO_(4))and phosphite(0.5mmol/L KH_(2)PO3).The morphological,physiological indicators,and expression of genes related to phosphorus absorption and metabolism of alfalfa seedlings were examined on 4,8 and 12 d.The results showed that compared with the control,the above-ground biomass of seedlings under phosphite and low phosphate treatments decreased by 52%and 38%on 8 d,and by 44%and 16%on 12 d,respectively.The total phosphorus content of alfalfa roots increased by 34%at 12 d of phosphite stress but decreased by 68%at 12 d of low phosphorus treatment.Real-time quantitative PCR(qRT-PCR)results showed that the MsPHO1 gene was induced by phosphate deficiency on 4 d,which promoted the phosphorus transport and phosphate deficiency stress response in alfalfa.The expression of MsSQD2 was up-regulated on 12 d,which indicated that it may regulate the phosphorus balance in the plant by degrading the phospholipid membranes.Both low phosphate and phosphite treatments can induce the expression of MsPHT2 gene,promoting the absorption of exogenous phosphate.Overall,the growth of aboveground and underground parts of alfalfa was inhibited under phosphate deficiency and phosphite stress treatments.Furthermore,the inhibition of aboveground parts of alfalfa under phosphite stress was greater than that of low phosphate treatment,and the alfalfa roots absorbed phosphite more efficiently.Therefore,alfalfa can adapt to phosphate deficient environment by inhibiting plant growth,increasing root phosphorus absorption,and regulating expression of genes related to phosphate absorption.

关 键 词：紫花苜蓿 亚磷酸盐 低磷酸盐 磷转运蛋白 

分 类 号：S541.1[农业科学—作物学]