陆地棉MGDG基因家族低磷胁迫下的表达分析

Expression Analysis of the MGDG Gene Family of Gossypium hirsutum L.under Low Phosphorus Stress

单半乳糖甘油二酯(monogalactosyl diacylglycerol, MGDG)是植物光合膜的重要组成成分,在植物抵御不利环境过程中具有调控作用。研究利用生物信息学方法对陆地棉MGDG基因家族(GhMGDs)进行了全基因组鉴定,并验证其在低磷胁迫下的表达规律,为明确MGDG基因在陆地棉低磷胁迫中的作用奠定基础。结果表明:(1)该基因家族在陆地棉中有17个成员,氨基酸残基在435~888 aa之间,理论等电点在6.00~9.67,均含有6~8个内含子。(2)系统进化分析表明,该基因家族可分为A型和B型MGDG合成酶,各亚族内各成员基因结构和保守基序的数量和分布基本一致。(3)17个MGDG基因在7条染色体上呈现不均匀分布,二级结构均显示该家族主要由α-螺旋和无规则卷曲所组成。(4)qRT-PCR分析结果显示,MGDG基因在陆地棉4个不同组织中表达量有差异,其中GhMGD2、GhMGD12和GhMGD16在根的表达量最高,GhMGD7、GhMGD9和GhMGD10在叶的表达量较高。陆地棉MGDG家族GhMGD2、GhMGD7、GhMGD9、GhMGD10、GhMGD12和GhMGD16 6个候选基因均受低磷胁迫的诱导表达,GhMGD2基因在低磷处理72 h表达量是适磷处理的72倍。

Monogalactosyl diacylglycerol(MGDG)is an important component of plant photosynthetic membranes and plays a regulatory role in the resistance of plants to adverse conditions.The genome of MGDG gene family(GhMGDs)of Gossypium hirsutum L.were analyzed and identified by bioinformatics method,and verified its expression rule under abiotic stress in this study.The results showed that:(1)There were 17 members of this gene family in the upland cotton genome,the amino acid residues ranged from 435 aa to 888 aa,the heoretical isoelectric point ranged from 6.00 to 9.67,and all genes contain 6-8 introns.(2)According to the phylogenetic tree,this gene family can be divided into type A and type B MGDG synthetase.The gene structure and conserved motifs of each member of each subfamily were very similar.(3)The 17 MGDG genes were unevenly distributed on 7 chromosomes.The tertiary structure models were highly similar,and The secondary structures showed that the family was mainly composed ofα-helix and random coil.(4)The results of qRT-PCR analysis showed that the expression analysis of MGDG gene family members were the difference in the expression levels of each MGDG gene in four different tissues of Upland cotton.GhMGD2,GhMGD12 and GhMGD16 genes were highly expressed in upland cotton roots.GhMGD7,GhMGD9 and GhMGD10 genes were highly expressed in upland cotton leaves.Furthermore,we identified six candidate gene expression patterns induced by low phosphorus stress,including GhMGD2,GhMGD7,GhMGD9,GhMGD10,GhMGD12 and GhMGD16.The expression of GhMGD2 gene at 72 h under low phosphorus treatment was 72 times that of suitable phosphorus treatment.This experimental study shows that upland cotton MGDG gene family played different roles in response to cotton low phosphorus stress,which provided a theoretical basis for the study of cotton low phosphorus stress resistance.