Cloning And Expression Analysis Of DELAY OF GERMINATION1(DOG1) Of Solanum Rostratum Dunal

Solanum rostratumDunal is an annual weed of the family Solanaceae and isnative to North America.It is a highly dangerous quarantine pest with strong competitiveness and adaptability,seriously affecting the local ecological balance.S.rostratum propagated only by seed.Its seeds have a strong dormancy,and Delay of germination 1(DOG1)is a specific gene related to seed dormancy.We cloned the DOG1 gene of S.rostratum,and detected the expression level of SrDOG1 gene at different developmentalstages of S.rostratum.The conclusions obtained are as follows:1.The full-length of SrDOG1 gene is 753 bp with no introns,and totally encoding 250 amino acids.It was found that SrDOG1 showed highest identities to SlDOG1(81%)and StDOG1(83%).?Furthermore,the molecular weight of SrDOG1 protein was 28 kDa and the theoretical PI was about 5.63,SrDOG1 protein is ?-type protein with no signal peptide;2.SrDOG1 gene was mainly expressed in dormant seeds.This result showed the expression level of SrDOG1 was increased along with extension of storage time.Moreover,the expression of SrDOG1 in cold storage seeds was 2 times higher than that in normal temperature showed that the low temperature could promote the expression of SrDOG1 in mature seeds.This result also suggested SrDOG1 transcript level was affected by environmental changes;3.The expression of SrDOG1 was significantly decreasedduring seed germination.After seed soaking,the expression of SrDOG1 in seeds reduced by 90%.This result suggested that seed soaking can significantly change the expression level of SrDOG1 in seeds.At training stage,the SrDOG1 transcript level was slightly increased,and reached the maximum when the seeds were germinated.After germination,the expression of SrDOG1 was again significantly reduced,and was only 1/20 of that in dry seeds.After that,The SrDOG1 transcript level remained essentially unchanged until radicle elongation to 2 cm.In general,seed germination can greatly reduce the SrDOG1 transcript level and the transcript level was maintained at a low level after germination;4.The expression of SrDOG1 in seeds is concentrated in embryo.The SrDOG1 transcript level in embryo was 5 times higher than that in the endosperm and 3 times higher than that in the endosperm cap.It is speculated that the seed embryo may be the main expression site of SrDOG1;5.SrDOG1 transcripts were detected in all the test organs(root,stem and leaf),although the expression level was very low.In root,the expression level was highest in the cotyledon stage,then decreased significantly.In stems,the expression level was lower than that in root,and no significant change in the whole plant growth stage.In leaves,the expression level was highest at the cotyledon stage,after this,SrDOG1 transcript level decreased significantly until almost undetectable;6.SrDOG1 is present in all reproduction organs.And in fructescence,SrDOG1 already expressed in fruit,although it was lower than that in seeds.The expression of SrDOG1 was highest in fruit at the mature stage,the second in flower at the fruit stage,and the lowest in the bud.This result showed that SrDOG1 may not only participate in the regulation of seed dormancy,but also participate in other life activities in plant life history.