| With long life time and easy to forest, mulberry has a strong vitality andadaptability, not only can green the environment, fix wind and sand, conserve thewater, purify the air, but also receive a good ecological effects and a highereconomic benefits.By research of physiology and transcriptome in mulberry cuttingsduring adventitious root formation, to provide theoretical support for innovation offast breeding technology in mulberry, can promote the preservation of fine localmulberry varieties and improve the quality and yield of mulberry, which hasimportant significance.The mechanism of cutting rooting has been discussed with the analysis of therelated physiological and biochemical indicators during adventitious root formationof mulberry. A genome-wide gene expression profiling was conducted by Solexasequencing to investigate the transcriptome dynamics associated with the earlydevelopment of mulberry adventitious root development.We found that many genesup-or down-regulated from the sequencing result, which revealed the complexitychanges of the transcriptome. And MaGH3.6gene, which significantly differentiallyexpressed in the formation of adventitious root, were analyzed by cloning,expression pattern analysis, phylogenetic analysis and functional verification.The main results and conclusion were as follows:1. Soluble sugar and soluble protein content is a downward trend. Soluble sugarhave a progressively increase in the later stage.The activities of IAAO increasedgradually and maintained at a higher level of activity in the early stage and late stage,the active did not change significantly in the intermediate stages. The activities ofperoxidase in the whole cutting process, showed the variation of the "U" type.2. A genome-wide gene expression profiling was conducted by Solexasequencing to investigate the transcriptome dynamics associated with the earlydevelopment of mulberry (Morus alba L.) adventitious root development.Approximately7.66G to8.89G sequence reads were obtained from fourdevelopmental stages, and de novo assemblies yielded66556to69087contigs. Theannotated23837(35.81%) to39504(57.20%)\contigs showed significantsimilarity with the sequences present in public databases. A total of332,6381, and842genes demonstrated significant changes in the S1vs. S2, S2vs. S3, and S3vs. S4libraries. Several functional groups of genes involved in important pathwayswere differentially expressed, including the hormone signal transduction pathway,cell division and differentiation, carbohydrate metabolism and energy metabolism.Some genes were randomly selected to confirm their altered expression levels usingquantitative real-time polymerase chain reaction. This study provides a fairlycomprehensive molecular biology background on adventitious root formation.3. In this study, a GH3（gretchen hagen3） gene was cloned from mulberry andnamed MaGH3.6.（GenBank accession number: KC349982）。The bioinformatics’analysis showed that the gene encodes611amino acids and has a molecular mass ofabout68.87KD without transmembrane region and signal peptide, and the proteinsequence is quite conservative. Expression levels of MaGH3.6were significantlyincreased within half an hour and gradually increased with time.The effect of NAAinducing MaGH3.6was better than IAA. cDNA libraries date analysis which wereconstructed by Solexa mRNA sequencing showed that the expression level ofMaGH3.6gene were significantly decreased in the stage of the root primordial androot–like protrusions formation. It may cause to increase IAA content, which in turnto promote the formation and development of the adventitious root of the cuttings.Comprehensive analysis prompted that MaGH3.6can be induced to express,suggesting that the gene down-regulated may lead to increased IAA content, whichin turn promote adventitious root formation and development of the cuttings.Preliminary view is that the gene plays an important role in the rooting process ofmulberry cuttings. |
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