| Medicago truncatula,whose genome is relatively small,belongs to the genus leguminosae with high efficiency of genetic transformation,Is the third genome-wide sequenced model plant following sequencing of genome-wide sequences in Arabidopsis thaliana and Oryza sativa.Because of its close relationship with legumes such as alfalfa(Medicago sativa L.),the study of related genes can also provide reference and reference for alfalfa(Medicago sativa L.)and other legumes.The Medicago truncatula was treated with drought for different durations(0,3,8 h),and the leaves treated with different treatments were used for transcriptome analysis,and each treatment was repeated 3 times for a total of 9 samples.Through transcriptome data mining and weighted co-expression network analysis,a weighted co-expression network was constructed to explore the mechanism of proline accumulation under drought stress,and three key modules were found.The LightCyan module was the most relevant(cor=-1).The aldehyde dehydrogenase gene family gene Medtr2g042330 with higher module membership(MM)was identified,and the aldehyde dehydrogenase gene family was identified in the whole genome: Medtr2g042330 was named MtALDH7A1,and molecular experiments were carried out: Firstly,the expression pattern of MtALDH7A1 gene in the aboveground and underground parts under different drought treatments was detected by real-time fluorescence quantitative PCR.The accuracy of transcriptomic analysis data was verified.1300::35S::GFP plant vector was obtained,and a homozygous MtALDH7A1 transgenic Arabidopsis thaliana plant was obtained and a preliminary functional study was performed on the overexpressed plants.The main results are as follows:1.Comparing the three stages of drought treatment,5747,9096,4059 differential genes were found(Fold changeā„2,FDR<0.05),and all the differential genes were clustered and copolymerized into 8 categories,of which three stages were up-regulated.The genes that were up-regulated in three stages were 948 genes,and the genes that were down-regulated were 1306 genes.Venn analysis showed that a total of 969 differentially expressed genes were differential genes shared by the three stages.The above 3223 genes were used as follow-up genes for the study.2.In order to further screen the genes closely related to proline metabolism,a weighted co-expression network with high topological properties was constructed,and 10 gene co-expression modules were obtained.Among them,three key modules were found.The LightCyan module has the highest correlation.The LightCyan module identified a higher module identity value(MM)for the aldehyde dehydrogenase gene family(ALDH)gene Medtr2g042330.3.Based on 14 ALDH genes of Arabidopsis thaliana,28 ALDH gene family members were identified in the Medicago truncatula genome using the BLAST method,And named Medtr2g042330 as MtALDH7A1 according to the standard established by the AGNC.4.The transgenic plants were obtained by transferring MtALDH7A1 into Arabidopsis thaliana,and subjected to salt and drought treatment for preliminary functional verification.The results showed that overexpression of MtALDH7A1 increased salt stress and drought stress by affecting root growth and increasing number of lateral roots. |
