Analysis Of Drought-resistance Physiology And Screening Of Drought-resistance Genes In Centipedegrass

With the development of the economy,the degree of utilization of turfgrass in China has gradually increased,and the centipedegrass that has always been a "lazy grass" is facing difficulties in planting due to drought caused by lack of water.Understanding the drought-resistance mechanism of centipedegrass can provide theoretical support for drought-resistant breeding of centipedegrass.In this study,drought-resistant physiological and biochemical identification and transcriptome sequencing analysis of drought-resistant mutants 22-1 and wild-type 3-1 under drought stress were analyzed.As a result of the data,several drought-related genes were cloned and preliminary analyzed.The main findings are as follows:1)Drought stress affects the growth and development of centipedegrass.With the prolongation of drought stress,the leaves wither,the chlorophyll content,the chlorophyll fluorescence value and the relative water content of the leaves decrease,and the relative conductivity of the leaves increases.The drought-resistant mutant 22-1 had higher chlorophyll content,chlorophyll fluorescence value,and relative water content in leaves than wild-type 3-1,and its relative electrical conductivity was lower than that of wild-type 3-1.2)Drought stress severely affected the physiological activity of centipedegrass,and the antioxidant enzymes SOD,CAT,and POD showed a trend of first increase and then decrease,and the MDA content and proline content increased.The drought-resistant mutant 22-1 had higher antioxidant enzyme activity than wild type 3-1,and had less accumulated MDA and proline than 3-1.3)Through transcriptome sequencing,a total of 159192 Unigenes were obtained.A total of 51094 genes were significantly differentially expressed in roots and leaves.77.77%of the transcripts were annotated.GO functional annotations accounted for 48.1%,30%,and21.9% of the three categories of biological processes,cellular components,and molecular functions,respectively.In the root system,GO enrichment is mainly based on protein phosphorylation in biological processes,adenosine diphosphate binding and lipid binding in molecular functions,and in leaves,carbohydrate derivatives binding,transferase activity,and transition metal ion binding,Mainly.4)A total of 39,305 Unigenes were annotated into the KOG database,mainly annotations of T-ranslation,ribosome structure and biogenesis,Posttranslati-onal modification,protein turnover,chaperones.Plant hormone signal transduction,Phenylpropanoid biosynthesis,carotenoid biosynthesis,and photosynthesis are significant enrichment pathways in the KEGG annotation and KEGG metabolic pathways.5)Through analysis,a total of 51960 SSR loci,6,25079 SNPs and 216235 Indels were identified.After analysis of the WGCNA gene co-expression network,eight drought-related modules were obtained.6)Drought-related genes Eo MYB3R-3,Eo MYB41,Eo WRKY65,and Eo HOX14 were cloned.Analysis of related biological information showed that the four genes contained an open reading frame of 849 bp,1032bp,906 bp,and 690 bp in sequence,encoding 282,343,301,229 Amino acid,protein subcellular localization shows that Eo MYB3R-3 gene is located outside the cell and the rest is located in the nucleus.The homologous evolutionary tree shows that centipedegrass is relatively close to grasses such as sorghum and corn,and far from oil palm and plantain.