| The drought has become one of the important world's ecological problems and is also a key factor restricting agricultural sustainable development.Coix(Coix lachryma-jobi L.)commonly known as Job's tears,is a member of the grass family in the tribe Maydeae,which is an annual crop that has long been consumed as both an herbal medicine and a nourishing food.Coix is not only a nourishing food including nutrients with abundant proteins and lipids but also has important medicinal effects.With health care functions of coix,the market demand of the coix has become more and more big.Therefore,coix cultivation has a broad market and prospects.While,Coix lachryma-jobi L.is a crop of being keen on water,which habits are similar to rice.Therefore,drought is a key factor restricting coix agricultural production.As a member of the triazole PRGs family,uniconazole was increasingly applied in crops as a plant growth retardant,which has played an important role in plants stress resistance.In this work,“No 5 Yiliao” as the material and PEG 6000 simulating drought stress.The effects of uniconazole on growth and physiological indicators of coix seedling were studied.Meanwhile we applied Illumina sequencing technology to explore the coix transcriptome analysis under drought stress and the effect of S3307 on coix transcriptome under drought stress,And then,the differentially expressed genes being generated by de novo assembly were annotated,analyzed and verified,the main results were as follows:1.The influence of S3307 on seed germination under PEG drought stressThe seed germination rate,germination potential,germination index and vigor index of coix showed a trend of decline under drought stress.12 h after S3307 treatment,the seed germination rate,germination potential,germination index also showed a trend of decline under drought stress,however,vigor index showed a trend of earlier increasing and later decreasing and reached a maximum(3.52±0.38)at S3307(9 mg·L-1),which enhanced 51.7% than drought stress group.Meanwhile,the weight of embryo radical and root also reached maximum(0.40±0.02mg·10seedling-1,0.22±0.03 mg·10seedling-1)and increased by 12.50% and 22.27%.2.The influence of S3307 on seedling growth and physiological indicators under PEG stressCoix plant height,root length,stem thicker and biomass showed a decline trend underdrought stress.The stem thicker enhanced 16.19%,above-ground and blow-ground biomass increased 19.56% and 22.75% than drought stress group at at S3307(9 mg·L-1).The antioxidant enzymes and osmotic substances presented a significant difference with drought stress group,which CAT activity of leaf and root enhanced 80.56% and 50.96% respectively,proline contents being increased 28.49% and 4.58%.3.The influence of S3307 on seedling ultrastructure and endogenous hormone under drought stress.The stomatal length,stomatal width,stomatal opening degree of Coix were obviously decreased and coix seedlings ultrastructure were damaged in different extent under drought stress.Stomatal density,width of stomatal,stomatal opening degree of S3307 group increased by20.43%,10.49% and 28.97% after 48 h,respectively.Meanwhile,S3307 can alleviate coix seedlings ultrastructure damage and can make root cell mitochondria and chloroplasts basic returned to normal,such as plasmolysis phenomenon being alleviated.And then,S3307 could be response to drought stress by regulating content of ABA,GA3 and IAA.4.The transcriptome analysis of coix seedling leafIn this study,coix transcriptome database was established.173,786 transcripts and 92,865 unigenes were acquired by using I11 umina Hi Seq2000 high throughput sequencing technology.Meawhile,the expressed genes sequences were assembled,function being annotated and mebabolic pathway were analyzed,which obtained functional genes and metabolic pathways.In addition,7534 simple sequence repeats were detected.5.The differential gene expression analysis of the coix transcriptome under PEG stressBy the expression profiles of coix high throughput sequencing,the 1128 differentially expressed genes were achieved,including 662 and 466 genes that were up-regulated and down-regulated,respectively.According to the GO,COG and KEGG analysis,coix being in response to drought stress mainly reflected in plant hormone signal transduction and sugar metabolism.In annotated differential expression genes,ABA and NCEDs aldehyde oxidase related to ABA synthesis,some transcription factors related to drought(AP2,NAC,b ZIP and EREBP)and some functional protein(LEA,HSP70 and protein kinase)were up-regulated significantly.6.The transcriptome analysis of S3307 on coix seedlings under drought stressBy the expression profiles of coix high throughput sequencing,the 212 differentially expressed genes were achieved,including 103 and 212 genes that were up-regulated and down-regulated,respectively.According to the GO,COG and KEGG analysis,S3307 being in response to drought stress mainly reflected in linoleic acid metabolism and oxidative phosphorylation metabolic pathway.In annotated differential expression genes,some related to lipid metabolism(lipoxygenase and linoleate 13S-lipoxygenase)and some related to oxidation reduction(cytochrome P450,monooxygenase and alcohol dehydrogenase NAD)were up-regulated significantly.Meanwhile,some related to enzyme of flavonoids and brassinosteroid synthesis also were up-regulated significantly.The results indicated that seedling morphology and physiological function of coix seedlings seriously affected under drought stress.While,S3307 could enhance drought tolerance of coix seedlings through increasing stem diameter and biomass,enhancing antioxidant enzyme activity and osmotic substances,improving membrane structure etc.Meanwhile,The differentially expressed genes analysis of drought and S3307 treatment was discussed from the transcription level.And,some differentially expressed genes related to drought and drought resistance were achieved by the expression profiles of high throughput sequencing,which can provide a theoretical basis and gene resources for coix drought resistant study and S3307 in coix production and practice of drought resistance. |
PDF Full Text Request