The Cloning And Expression Analysis Of GA20ox And GA3ox During The Flower Development In Three Viola Species

Viola philippica,Viola prionantha and Viola tricolor are all plants of the Viola.Viola philippica and Viola prionantha both exhibit typical two types of self-fertilization.Under short sunlight,open flowers(Chasmogamous,CH)are formed,while under long sunlight,cleistogamous flowers(CL)are formed.The photoperiod did not affect the flower pattern of Viola tricolor.The research team found in the early stage that the content of active GAs in the closed flowers corresponding to long-day sunlight is higher than that in the open flowers corresponding to short day sunlight in Viola philippica.However,The expression level of B-class MADS-box genes is higher under short day exposure than under long-day exposure.Viola prionantha is closely related to Viola philippica,which belongs to dimorphic flower plants of Viola,and Viola tricolor belongs to non dimorphic flower plants of Viola.Therefore,in this paper,we studied the response of GA20 ox and GA3 ox genes to photoperiod and their interaction with B-class MADS-box transcription factors in the flower buds of Viola prionantha and Viola tricolor,and further explored the molecular development mechanism of the dimorphic flower.The main results of this study are as follows:1.GA20ox genes were isolated from Viola prionantha and Viola tricolor,with lengths of 1185 bp for Viola prionantha gibberellin 20 oxidase(Vpr GA20ox)and 1185 bp for Viola tricolor gibberellin 20 oxidase(Vtr GA20ox).GA3 ox genes were isolated from Viola prionantha and Viola tricolor,with lengths of 1134 bp for Viola prionantha gibberellin 3 oxidase(Vpr GA3ox)and 1185 bp for Viola tricolor gibberellin 3 oxidase(Vtr GA3ox).2.The total lengths of VprGA20ox and VtrGA20ox gDNA were separated to be1565 bp and 1477 bp,The total lengths of Vpr GA3 ox and Vtr GA3 ox g DNA were separated to be 1704 bp and 1601 bp.3.The length of GA20ox and GA3ox promoter isolated from Viola prionantha and Viola tricolor was 1840 bp for Vpr GA20 ox,1726 bp for Vtr GA20 ox,1804 bp for Vpr GA3 ox and 3100 bp for Vtr GA3 ox.GA20ox and GA3 ox promoters in three species of Viola all have photoresponsive elements and B-class MADS-box transcription factor binding elements(CAr G-box),there are differences in both types and quantities.4.Through yeast hybridization,the B-class MADS-box transcription factors Vpr TM6-1,Vpr PI,and Vpr AP3 interact with the CAr G-box elements on the GA20 ox and GA3 ox promoters of In Viola prionantha.In Viola tricolor,the B-class MADS-box transcription factors Vtr TM6-2,Vtr PI,and Vtr AP3 only interact with the CAr G-box elements on the promoters of Viola tricolor GA20 ox.5.Under different photoperiods,with the extension of lighting time,the expression levels of Vpr GA20 ox,Vph GA20 ox,Vpr GA3 ox,and Vph GA3 ox gradually increase.The expression levels of Vtr GA20 ox and Vtr GA3 ox did not change significantly with the change of lighting time.Under the photoperiod conversion of Viola philippica and Viola prionantha,the expression levels of Vpr GA20 ox,Vph GA20 ox,Vpr GA3 ox,and Vph GA3 ox gradually increased and then decreased to stabilize during the conversion of10h/14 h photoperiod to 16h/18 h photoperiod.The expression levels of Vpr GA20 ox,Vph GA20 ox,Vpr GA3 ox,and Vph GA3 ox gradually decreased and then increased to stabilize during the conversion of 16h/8h photoperiod to 10h/14 h photoperiod.This study cloned the GA20ox and GA3ox genes and promoters from three species of Viola,and investigated the effects of different photoperiods on the expression of GA20 ox and GA3 ox genes.The expression of GA20 ox and GA3 ox genes in Viola philippica and Viola prionantha were higher under long sunshine than under short sunshine,but there was no significant change in Viola tricolor.At the same time,it was found that the CAr G-box on the GA20 ox and GA3 ox promoters of Viola prionantha interacted with B-class MADS-box transcription factors,while only the CAr G-box on the GA20 ox promoter of Viola tricolor interacted with B-class MADS-box transcription factors.In summary,it has preliminarily revealed the important roles of photoperiod,GA,and B-class MADS-box genes in regulating plant flower development in dimorphic flower plants in the Viola,which can provide theoretical basis and practical guidance for plant breeding and production.